I built a small tool to clarify how much late fee a landlord can legally charge (and when) in each U.S. state.
Rent laws vary widely: some states set a fixed dollar cap, others a percentage, and a few use only “reasonable” language that’s open to interpretation. Many renters and landlords have no easy way to check what’s actually allowed without reading the statutes themselves.
This project compiles those laws into an instant calculator. Enter rent amount, due date, payment date, and state — it shows the lawful late fee limit, grace period rules, and citation.
It started as a curiosity after seeing conflicting answers online. The goal is transparency, not advocacy; all data is drawn from current state statutes.
The app is lightweight, built in Replit, and runs entirely client-side. I’d be interested in feedback on legal interpretation consistency, data sourcing, or UI clarity.
Utah appears to be calculating incorrectly, the text says "10% of rent or $75, whichever is GREATER." But it is doing the opposite, showing the lessor of 10% or $75.
I always thought Replit was supposed to be a pastebin site with built-in sandboxed code execution, so people could demo Python snippets and what-not. What happened?
I love the ambiguity in who the tool is for. For renters, learning about their rights and fighting illegal fees. For landlords, charging the maximum amount permitted under the law.
Here on Long Island (NY), most apartments are illegal (addition/remodeled single-family homes). Many of them make you sign a lease, anyway, but they can get dismissed by any law student.
Every now and then, some municipality claims that it will be "fighting illegal apartments," but they die quick deaths. If they got serious about it, the homeless population would explode, and a lot of folks would leave the state.
Also, I believe that most of the rules that apply to apartments, come from municipalities, not states.
This is the failure mode of bureaucratic government. The personality type of bureaucrats means that the rules will proliferate endlessly. Karens never sleep. Eventually the rules get so onerous that it becomes impossible to comply and everybody operates in violation of the rules. Everybody know that actual enforcement of the rules would be catastrophic, so they noncompliance is ignored. The economy reverts to the same unregulated and "unfair" state that the ruling Karens feared in the first place, but arbitrary enforcement continues anyway as the bureaucrats need to justify their existence by continually enforcing the rules. The number one rule of business becomes "keep your head down" because anything that attracts the attention of the bureaucrats will be immediately enforced, while the other 99% of violators are allowed to peacefully continue violating. Stagnation and slow decay takes hold as any sort of disruptive innovation is instantly shut down.
The "true" failure mode is bureaucrats discovering they can collect bribes from 99% of businesses to not enforce the rules, since nobody notices noncompliance and enforcement is expectedly arbitrary.
When I am dictatorKing, I will make the first line of the constitution (which won't matter because I'm dictatorKing (yes, the camelCase is important (yes I'm nesting parentheses))) be that a mandatory and invulnerable defense against any crime, claim, or tort is that the law is not enforced regularly.
How does that work for something like speeding, where they will charge you with everything, then let you off with a different infraction that doesn't actually have anything to do with the laws you supposedly broke.
They do that enough times, and all of a sudden now speeding is legal because no one was charged with speeding, but with "driving with an invalid instrument".
This would basically get rid of the "easy plea downs" and basically make fighting against the book the norm.
IRL example:
I once pulled out of my driveway and passed a stopped school bus (with lights on, but no stop signs extended) on a divided highway (barrier between my side of the road and theirs), a cop saw me do that, went around the barrier and pulled me over a couple minutes later. I was charged with something that was going to instantly take my license away.
I went to my local courthouse on the designated day, the prosecuter brought me in and told me he would drop the charges to failure to stop at a stop sign. I said I didn't pass a stop sign, and that the bus didn't have them extended, just stopped with lights on, across a highway from me.
Prosecutor said, that I'm allowed to argue that in front of a judge along with paying some large sum, and potentially lose my license, or take a point, and pay $150 today and be done with it.
>Here on Long Island (NY), most apartments are illegal (addition/remodeled single-family homes). Many of them make you sign a lease, anyway, but they can get dismissed by any law student.
What does this mean in practice? Courts won't enforce late fees or unpaid rents? Landlords can't evict bad tenants? Renters can terminate leases without any penalty?
> Landlords get in a lot of trouble, for renting illegal apartments.
Do you have a source for this because I’m not convinced. Maybe a small portion do but the majority face no penalties. When I was in college the number of questionably legal homes for rent was insane, but I didn’t have time to go after them. A friend of mine did and won, but it required a lot of time. Most of the time the landlord does what they want and the renters don’t have the resources to go after them.
You make it sound like it’s the renters who take advantage of the landlords but most of the time it’s the landlords who do whatever they want. The ones who stopped paying rent probably were doing so legally because a lot of them were forced to not work.
In this case it sounds like "do whatever they want" for the landlords means entering into a mutually agreed upon contract to rent their house when they aren't allowed to by the nonsensical nitpicky rules. But "do whatever they want" for the tenants means squatting. So, yeah, it sounds like the tenants are the ones taking advantage. Tenants can get away with murder.
Anything legal involves time and effort, but you certainly cannot do a "rapid eviction" on an illegal or unscheduled apartment.
Landlords naturally (e.g., by the nature) have the upper hand because they have the desired thing - the rental.
Tenants often have the legal upper hand, but the whole job of the landlord (even good ones!) is to work out which tenants know how to play the game and not rent to them.
Yes, at least in some towns on the US east coast, if you didn't register your rental with the town. And not only that, but you also would have to pay treble damages and all moving costs associated with them vacating your illegal rental.
It’s not the homeless population, it’s more to do to with the folks who own the apartments. Local politics and local real estate are birds of a feather.
Everybody wants to charge as much as he can. Workers do the same: we all want to charge as much for our labour as possible. Unions do the same thing too.
Everyone also wants to pay as little as he can, too.
Fortunately, as long as there are many buyers and many sellers, the market tends to find efficient prices. When there is a monopoly or a monopsony, though, prices get out of wack.
One thing I've noticed is that our current economic model, which builds in constant inflation, forces buyers and sellers to have this conversation non-stop. Why are prices higher? Because our costs are higher. Or because everyone else is charging more. Didn't you just raise prices recently? Yes...
If you don't increase your prices with inflation, your business will not be sustainable in the long term.
Not everybody everybody. Some people want to charge/pay/receive the maximum reasonable amount. Where "reasonable" is informed by social norms. The existence of so many amoral corporations, and sociopathic individuals running them, has absolutely skewed social expectations though.
Such people are certainly less common, but they do exist (anecdata of one, me)
My experience is that kids have to be taught “‘fair’ is what the market will bear” because they start out feeling quite strongly that it’s not true.
Tons of kids aren’t taught that, some of them start businesses, and they may struggle to make ends meet (or at least to thrive like they could be) because raising prices to market rates feels so unfair to them that they won’t do it unless prodded to and told it’s ok by someone else (and they still might not)
I definitely am not convinced market-rate-is-ethical-and-fair is natural thinking for most people, or the kind of thing they want to do.
(I’ve been the one telling people they should raise prices and I still can’t shake the feeling that it’s kinda wrong…)
> kids have to be taught “‘fair’ is what the market will bear”
Because it seems like the normal default for humans is that "fair" means when I sell something I take the highest offer I can get, but when I buy things the seller should give me the lowest offer he can while meeting his expenses or he is being "greedy." If you don't believe me just read the HN comments on any financial topic.
If you look at the other tools on the page, there's stuff for property-management and sending rent-reminders. I guess they know what part of their userbase is the most moneyed.
I thought this would be for tenants, but this seems more geared towards landlords. Most landlords have some kind of SaaS platform that will automate all of this for them as part of rent collection, I don't think you'll get many bites on this TBH.
I'd love to see some kind of 50 state tenant resource center, geared towards providing tenants with advice and legal resources.
Based on how inaccurate the information is and the fact that there is no support for local (city, county, town, etc.) regulations, I would say it was a very simple prompt to an LLM with no additional verification.
This looks something that could work nicely with my calculation DSL (https://github.com/amuta/kumi) This is one of the scenarios that was in my head: auditable/exportable/reusable tax-related calculations schemas.
I don't know how I feel about the concept of late rent fees...
On one hand, you did agree to the payment schedule when you signed the lease, but on the other hand, tacking on fees to someone who is already struggling to pay, to support mainly parasites responsible for creating a lot of the issues facing young people, is also not great.
People are lazy. Without penalties, nobody will ever pay a bill. Doesn't matter if they are rich or poor. They could have $1mm cash sitting on their desk and unless you motivate them, they're just not going to open the bill.
That's just the reality of sending bills or invoices. Half the time it's not about malice, just no reason to bother being timely.
This is simply not true, the vast majority of people continued to pay their bills and rent on time through Covid despite financial pressures and suspension of most penalties.
The cases of abuse are so egregious precisely because most people were just normal well meaning people doing their best to meet their obligations.
Being a landlord is one of the most directly parasitical things a person can do to another person.
I see all the bugs here about how it minimizes fees by reversing a particular comparison, and for a second I got excited -- maybe it's a subversive site? But no, just AI blunders.
Renters will always exist, and some will be unable or unwilling to adhere to the contract they signed. Like all contracts, there are penalities for non-compliance (on both sides).
Yep. A lot of these regulations end up hurting small landlords because only corporate landlords with a large number of units can comply easily and absorb costs of bad tenants.
Our society prioritizes the narrow interests of rentier capitalists over the working class. Unfortunately this means the US is losing international competitiveness across more and more industries. For one thing rent extraction ultimately gets financed by employers through higher wages, thus productive business loses out to business from a region like China where costs of employment are lower. Rather than making economies more efficient like productive business is supposed to do, rentier capitalism means cash flows from the debtor to the creditor class, which forms a feedback loop as the creditor class is able to use this cash to buy more assets and extract more rent simply by expanding its circle of ownership.
Real estate prices are controlled by supply and demand. If you want a lower cost of living than desirable places in the US, alternatives (like China, or the Rust Belt) exist.
And if you think housing prices are bad in the US, you should look at the rest of the developed world.
At least for North Carolina, it's wrong/self-inconsistent. The quoted text (and linked NC legislation) says the max is:
> $15 or 5% of rent, whichever is GREATER. 5-day grace period. One-time fee per late payment.
But this site seems to say the legal maximum is whichever is lower (i.e., it won't go above $15).
There are laws at the county and city levels as well as state levels. So this is insufficient.
I built a small tool to clarify how much late fee a landlord can legally charge (and when) in each U.S. state.
Rent laws vary widely: some states set a fixed dollar cap, others a percentage, and a few use only “reasonable” language that’s open to interpretation. Many renters and landlords have no easy way to check what’s actually allowed without reading the statutes themselves.
This project compiles those laws into an instant calculator. Enter rent amount, due date, payment date, and state — it shows the lawful late fee limit, grace period rules, and citation.
It started as a curiosity after seeing conflicting answers online. The goal is transparency, not advocacy; all data is drawn from current state statutes.
The app is lightweight, built in Replit, and runs entirely client-side. I’d be interested in feedback on legal interpretation consistency, data sourcing, or UI clarity.
Utah appears to be calculating incorrectly, the text says "10% of rent or $75, whichever is GREATER." But it is doing the opposite, showing the lessor of 10% or $75.
New Hampshire has the same bug.
Other states do as well.
"We compile state-level rent late-fee rules from official statutes and housing authority publications with AI-powered consistency checks."
Needs a higher-powered AI, I'd say.
Given that OP said it was "built in Replit"[1], I'm tempted to believe AI misgenerated the underlying calculation code.
[1] Replit bills itself as "an AI-powered platform for building professional web apps and websites."
I always thought Replit was supposed to be a pastebin site with built-in sandboxed code execution, so people could demo Python snippets and what-not. What happened?
Vibe-coding webapps raise more money
see: https://news.ycombinator.com/item?id=45486035
tl;dr: they pivoted from offering services adjacent to "learn to code" (among other things) to vibecoding
I love the ambiguity in who the tool is for. For renters, learning about their rights and fighting illegal fees. For landlords, charging the maximum amount permitted under the law.
Or landlords who want to follow the law, but aren't sure what it is, trying to make sure they are doing things right.
Here on Long Island (NY), most apartments are illegal (addition/remodeled single-family homes). Many of them make you sign a lease, anyway, but they can get dismissed by any law student.
Every now and then, some municipality claims that it will be "fighting illegal apartments," but they die quick deaths. If they got serious about it, the homeless population would explode, and a lot of folks would leave the state.
Also, I believe that most of the rules that apply to apartments, come from municipalities, not states.
This is the failure mode of bureaucratic government. The personality type of bureaucrats means that the rules will proliferate endlessly. Karens never sleep. Eventually the rules get so onerous that it becomes impossible to comply and everybody operates in violation of the rules. Everybody know that actual enforcement of the rules would be catastrophic, so they noncompliance is ignored. The economy reverts to the same unregulated and "unfair" state that the ruling Karens feared in the first place, but arbitrary enforcement continues anyway as the bureaucrats need to justify their existence by continually enforcing the rules. The number one rule of business becomes "keep your head down" because anything that attracts the attention of the bureaucrats will be immediately enforced, while the other 99% of violators are allowed to peacefully continue violating. Stagnation and slow decay takes hold as any sort of disruptive innovation is instantly shut down.
The "true" failure mode is bureaucrats discovering they can collect bribes from 99% of businesses to not enforce the rules, since nobody notices noncompliance and enforcement is expectedly arbitrary.
When I am dictatorKing, I will make the first line of the constitution (which won't matter because I'm dictatorKing (yes, the camelCase is important (yes I'm nesting parentheses))) be that a mandatory and invulnerable defense against any crime, claim, or tort is that the law is not enforced regularly.
How does that work for something like speeding, where they will charge you with everything, then let you off with a different infraction that doesn't actually have anything to do with the laws you supposedly broke.
They do that enough times, and all of a sudden now speeding is legal because no one was charged with speeding, but with "driving with an invalid instrument".
This would basically get rid of the "easy plea downs" and basically make fighting against the book the norm.
IRL example:
I once pulled out of my driveway and passed a stopped school bus (with lights on, but no stop signs extended) on a divided highway (barrier between my side of the road and theirs), a cop saw me do that, went around the barrier and pulled me over a couple minutes later. I was charged with something that was going to instantly take my license away.
I went to my local courthouse on the designated day, the prosecuter brought me in and told me he would drop the charges to failure to stop at a stop sign. I said I didn't pass a stop sign, and that the bus didn't have them extended, just stopped with lights on, across a highway from me.
Prosecutor said, that I'm allowed to argue that in front of a judge along with paying some large sum, and potentially lose my license, or take a point, and pay $150 today and be done with it.
I chose the latter.
>Here on Long Island (NY), most apartments are illegal (addition/remodeled single-family homes). Many of them make you sign a lease, anyway, but they can get dismissed by any law student.
What does this mean in practice? Courts won't enforce late fees or unpaid rents? Landlords can't evict bad tenants? Renters can terminate leases without any penalty?
Pretty much.
Landlords get in a lot of trouble, for renting illegal apartments.
I have friends that rented apartments, and had Pacific Heights-type[0] problem tenants.
The COVID era was a horror. Many tenants just stopped paying rent entirely.
[0] https://en.wikipedia.org/wiki/Pacific_Heights_(film)
> Landlords get in a lot of trouble, for renting illegal apartments.
Do you have a source for this because I’m not convinced. Maybe a small portion do but the majority face no penalties. When I was in college the number of questionably legal homes for rent was insane, but I didn’t have time to go after them. A friend of mine did and won, but it required a lot of time. Most of the time the landlord does what they want and the renters don’t have the resources to go after them.
You make it sound like it’s the renters who take advantage of the landlords but most of the time it’s the landlords who do whatever they want. The ones who stopped paying rent probably were doing so legally because a lot of them were forced to not work.
In this case it sounds like "do whatever they want" for the landlords means entering into a mutually agreed upon contract to rent their house when they aren't allowed to by the nonsensical nitpicky rules. But "do whatever they want" for the tenants means squatting. So, yeah, it sounds like the tenants are the ones taking advantage. Tenants can get away with murder.
Anything legal involves time and effort, but you certainly cannot do a "rapid eviction" on an illegal or unscheduled apartment.
Landlords naturally (e.g., by the nature) have the upper hand because they have the desired thing - the rental.
Tenants often have the legal upper hand, but the whole job of the landlord (even good ones!) is to work out which tenants know how to play the game and not rent to them.
I probably could find references, but I’m not really up for arguing on the Internet.
The laws are quite harsh, but enforcement, not so much.
Yes, at least in some towns on the US east coast, if you didn't register your rental with the town. And not only that, but you also would have to pay treble damages and all moving costs associated with them vacating your illegal rental.
Yup. That treble-damages thing is a kicker. Can't get it, though, if they don't have it.
Most folks don't want to saw off the branch they are sitting on, though, so they play nice.
It’s not the homeless population, it’s more to do to with the folks who own the apartments. Local politics and local real estate are birds of a feather.
This is just a nicer way of saying what OP posted. "I want to charge as much as I can, but I want to follow the law and do things right."
Everybody wants to charge as much as he can. Workers do the same: we all want to charge as much for our labour as possible. Unions do the same thing too.
Everyone also wants to pay as little as he can, too.
Fortunately, as long as there are many buyers and many sellers, the market tends to find efficient prices. When there is a monopoly or a monopsony, though, prices get out of wack.
One thing I've noticed is that our current economic model, which builds in constant inflation, forces buyers and sellers to have this conversation non-stop. Why are prices higher? Because our costs are higher. Or because everyone else is charging more. Didn't you just raise prices recently? Yes...
If you don't increase your prices with inflation, your business will not be sustainable in the long term.
> Everybody
Not everybody everybody. Some people want to charge/pay/receive the maximum reasonable amount. Where "reasonable" is informed by social norms. The existence of so many amoral corporations, and sociopathic individuals running them, has absolutely skewed social expectations though.
Such people are certainly less common, but they do exist (anecdata of one, me)
Homo economicus does not actually exist.
My experience is that kids have to be taught “‘fair’ is what the market will bear” because they start out feeling quite strongly that it’s not true.
Tons of kids aren’t taught that, some of them start businesses, and they may struggle to make ends meet (or at least to thrive like they could be) because raising prices to market rates feels so unfair to them that they won’t do it unless prodded to and told it’s ok by someone else (and they still might not)
I definitely am not convinced market-rate-is-ethical-and-fair is natural thinking for most people, or the kind of thing they want to do.
(I’ve been the one telling people they should raise prices and I still can’t shake the feeling that it’s kinda wrong…)
> kids have to be taught “‘fair’ is what the market will bear”
Because it seems like the normal default for humans is that "fair" means when I sell something I take the highest offer I can get, but when I buy things the seller should give me the lowest offer he can while meeting his expenses or he is being "greedy." If you don't believe me just read the HN comments on any financial topic.
If you look at the other tools on the page, there's stuff for property-management and sending rent-reminders. I guess they know what part of their userbase is the most moneyed.
It's a tool, and like any tool it should be as neutral as possible.
I thought this would be for tenants, but this seems more geared towards landlords. Most landlords have some kind of SaaS platform that will automate all of this for them as part of rent collection, I don't think you'll get many bites on this TBH.
I'd love to see some kind of 50 state tenant resource center, geared towards providing tenants with advice and legal resources.
Curious what your process for gathering and verifying the legal information was
Based on how inaccurate the information is and the fact that there is no support for local (city, county, town, etc.) regulations, I would say it was a very simple prompt to an LLM with no additional verification.
for nj the legal source brings up a 404. https://www.nj.gov/dca/divisions/codes/publications/pdf_lti/...
This looks something that could work nicely with my calculation DSL (https://github.com/amuta/kumi) This is one of the scenarios that was in my head: auditable/exportable/reusable tax-related calculations schemas.
I don't know how I feel about the concept of late rent fees...
On one hand, you did agree to the payment schedule when you signed the lease, but on the other hand, tacking on fees to someone who is already struggling to pay, to support mainly parasites responsible for creating a lot of the issues facing young people, is also not great.
People are lazy. Without penalties, nobody will ever pay a bill. Doesn't matter if they are rich or poor. They could have $1mm cash sitting on their desk and unless you motivate them, they're just not going to open the bill.
That's just the reality of sending bills or invoices. Half the time it's not about malice, just no reason to bother being timely.
This is simply not true, the vast majority of people continued to pay their bills and rent on time through Covid despite financial pressures and suspension of most penalties.
The cases of abuse are so egregious precisely because most people were just normal well meaning people doing their best to meet their obligations.
Being a landlord is one of the most directly parasitical things a person can do to another person.
I see all the bugs here about how it minimizes fees by reversing a particular comparison, and for a second I got excited -- maybe it's a subversive site? But no, just AI blunders.
Sounds like a great tool. But it's sad that it needs to exist.
Sad in what way?
Renters will always exist, and some will be unable or unwilling to adhere to the contract they signed. Like all contracts, there are penalities for non-compliance (on both sides).
Yep. A lot of these regulations end up hurting small landlords because only corporate landlords with a large number of units can comply easily and absorb costs of bad tenants.
Our society prioritizes the narrow interests of rentier capitalists over the working class. Unfortunately this means the US is losing international competitiveness across more and more industries. For one thing rent extraction ultimately gets financed by employers through higher wages, thus productive business loses out to business from a region like China where costs of employment are lower. Rather than making economies more efficient like productive business is supposed to do, rentier capitalism means cash flows from the debtor to the creditor class, which forms a feedback loop as the creditor class is able to use this cash to buy more assets and extract more rent simply by expanding its circle of ownership.
Real estate prices are controlled by supply and demand. If you want a lower cost of living than desirable places in the US, alternatives (like China, or the Rust Belt) exist.
And if you think housing prices are bad in the US, you should look at the rest of the developed world.