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Calculate how much your client owes in late fees on their overdue invoice.
Late fee owed
$0.00
Total amount owed: $0.00
Late fees may be regulated in your jurisdiction. Check local laws before charging.
A late fee on a $25,000 invoice at 1.5 percent a month works out at $12.33 a day, or $591.78 after 48 days, when that rate was agreed in writing. Interest here is simple, on a 365-day year. In the United States the rate has to be in the contract first. In the UK it is the Bank of England base rate plus 8 percent, and in the EU the Late Payment Directive adds at least 40 euro of compensation.
A late fee is not a punishment for its own sake. It covers the extra work of chasing money you already earned. Reminder emails, bookkeeping, and the cash-flow hole all cost something. A fair fee is written into your invoice terms before the work starts, so the client is not ambushed on day 31.
Most small businesses pick one of three shapes. A modest monthly percentage, often around 1.5% of the unpaid balance. A small flat fee that fits tiny invoices where a percentage looks silly. Or annual interest converted to a daily amount for longer delays. Pick one method and use it every time. Mixing methods on the same client looks like you are making the number up.
Enter the original amount, how many days the invoice is overdue, and the rule you already published. The calculator returns the fee and the new total. That is the number you put on a reminder or a revised invoice. Do not invent a higher figure because you are angry. Angry fees do not get paid. Predictable fees sometimes do.
Local law can cap interest. Some countries treat late fees as credit charges. This page does arithmetic. It is not a ruling for your jurisdiction. If the amount is large or the client is in another country, ask an accountant. Then put the agreed rule in your Payment Terms Generator copy so every future invoice matches what you just calculated.
Nothing you type here is stored. Refresh and it is gone. That is fine for a one-off chase. If late invoices are a weekly event, Incusia can send the reminder sequence for you and, on Pro, apply late-fee automation. Starter is $9 per month with unlimited invoices, and that price is locked for the life of the account.
In the United States there is no statutory rate for an ordinary invoice. A late fee has to be agreed in writing before the work starts, or it is a request, and individual states cap what counts as reasonable. One to two percent a month, written into the contract, is the range most commercial invoices use. That is why this calculator asks for the rate instead of assuming one. A figure invented after the invoice went overdue is not a late fee.
In the UK, the Late Payment of Commercial Debts (Interest) Act uses the Bank of England base rate plus 8 percent on a commercial debt, with a fixed sum of £40, £70, or £100 depending on the size of the debt. Across the EU, Directive 2011/7/EU sets interest at the reference rate plus at least 8 percentage points, and compensation of at least 40 euro per invoice. Member states can set a higher margin. Those statutory totals belong on the UK and EU calculator. This page applies the rate you type.
Charging the fee is a relationship decision before it is a financial one. On a client you want to keep, the fee is often worth less than the conversation it starts. On a client who is late for the third time, the fee is the signal, and the signal is already late.
What changes the outcome is rarely the amount. It is whether the fee appeared on the day the invoice went overdue, or whether it turned up weeks later in an awkward email. The first reads as a system. The second reads as a person who has finally lost patience, and people argue with a person in a way they do not argue with a system.
Hi Tom,
Invoice INV-2026-092 for $18,750.00 was due on July 28. A late fee of 1.5 percent a month has been added, bringing the total to $19,286.30.
You can settle it here, and the fee stops growing the day it is paid.
Pay $19,286.30Enter the original amount, how many days the invoice is overdue, and the rule you already published: a flat fee, a monthly percentage, or annual interest. The calculator returns the fee and the new total. Use the same method every time so the number looks like a policy, not a mood. If your terms say 1.5% per month after 7 days, count only the days after that grace, not the days you spent being polite. Put the result on a revised invoice or a reminder that quotes the original clause. This page does arithmetic. It does not invent a rate you never wrote into the contract.
Most freelancers charge between 1% and 2% per month on overdue invoices, which works out to 12% to 24% annually. This is standard across most industries and generally considered legally reasonable. Some jurisdictions cap late fees, so check your local regulations. If you're just starting out, 1.5% monthly is a safe middle ground that most clients accept without pushback. The key is to include your late fee policy in your payment terms upfront, not as a surprise after the invoice is overdue. Run the number here, then paste the same rate into your terms so the reminder and the contract match.
Late fees can be enforceable when they were in the original written terms, the rate is reasonable, and you actually invoiced them. Surprise fees added after the fact are a fight waiting to happen. Rules vary by US state and by country. Some places treat high interest as a credit charge with extra disclosures. This calculator is not legal advice. Keep the rate modest, name it before the work starts, and show the math on the follow-up invoice. If the balance is large or the client is in another country, ask an accountant once, then reuse that clause. Angry, invented percentages rarely survive a dispute.
Put the rule on the original invoice. A fee that appears for the first time on day 40 feels like a punishment, even if the math is fair. State the percentage or flat amount in the payment terms block and, if you want, a one-line note near the total. You still calculate the actual dollars only after the due date plus any grace you promised. Clients pay faster when they can see the cost of waiting. You spend less time arguing later. If you forgot the clause on this job, do not bolt a new fee onto that PDF. Add it to the next agreement.
Trades often use a modest monthly percentage on the unpaid draw, not a huge flat fee that looks theatrical on a $40,000 progress bill. 1% to 1.5% per month after a short grace is common when the contract already named it. Lien rights and retainage are separate from late fees. Do not mix them on one angry line. Calculate the fee on the overdue progress amount only, show the days, and keep the original schedule visible. If the GC’s AP cycle is 45 days, your Net 15 plus late fees will just bounce. Match the contract, then use this calculator so the number is boring enough to approve.
This page shows the fee and the new total in the browser. It is a calculator, not a full invoice template. Copy the numbers onto a revised invoice or a reminder PDF so the client sees the original amount, the days overdue, the rate, and the new total in one place. There is no signup and nothing is stored when you refresh. If you want the revised invoice itself as a PDF, use the free invoice generator and add a late-fee line item. Incusia Pro can apply late-fee automation later. For one overdue bill today, the calculator plus a short PDF is enough.
A percentage fee grows with the unpaid balance and with time. A flat fee is one number, useful when the invoice is small and 1.5% of $80 looks petty. Simple interest applies the percent to the original unpaid amount. Compounding applies it to the amount plus earlier fees, which feels punitive and is harder to explain. Most freelance invoices should stay simple. If you cannot show the math on one line, do not use compounding. Pick one method, print it in your terms, and run this calculator the same way every time so you are not inventing a new theory per client.
No. Enter the amount, the days, and the rate. Read the result. Close the tab and it is gone. That is intentional for a one-off chase when you do not want another account. You also do not get a saved history of calculations, which is why you should paste the result into the invoice or your notes before you leave. If late invoices are a weekly event, Incusia can send reminders on a schedule and, on Pro, apply the fee you already named. Starter is $9 a month with the price locked. This page stays free either way.
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Incusia is invoicing software for people who send their own invoices.
It handles invoices, estimates, recurring billing, expenses and follow ups in one place, in any currency.
It is built for freelancers, sole traders and small businesses, not for finance departments.
Last reviewed 24 October 2026.