Free tool
Late payment fee calculator
Enter the invoice amount, your monthly interest rate and how many days late it is. You see the late fee and the new total as you type, and a clause to copy into your next contract.
Amount now owed
$2,030.00
- Invoice amount
- $2,000.00
- Interest (1.5% a month, 30 days)
- $30.00
- Late fee in total
- $30.00
- Interest per extra day
- $1.00
$2,000.00 × 1.5% × 30 ÷ 30 days, rounded to the cent.
Clause for your contract
Invoices are due within 14 days of the invoice date. Any amount still unpaid after the due date will carry interest of 1.5% per month, worked out daily on a 30-day month, from the due date until it is paid in full. Both parties agree to these terms by signing this agreement.
Put this in the contract or proposal before the work starts. A fee added only after an invoice is late is much harder to collect.
A late fee only works if it was agreed first.
In most places, you can only charge a late fee the client agreed to before the work started. Write the rate and any flat fee into the contract or proposal they sign, and repeat the due date on every invoice.
In the UK, a business can claim statutory interest on a late business-to-business invoice at 8% a year plus the Bank of England base rate, under the Late Payment of Commercial Debts (Interest) Act. A different rate in your contract replaces it. Source: gov.uk, checked 9 November 2026.
A fee helps once an invoice is late. A deposit before you start helps more. Here's how to ask for one.
This is general information, not legal advice. Rules on interest and late fees differ by country and state, so check what applies to you and your client.
Agree the late fee before the work starts.
Put your payment terms in the proposal itself. In ApeiroCraft the client signs them in the browser, and you see when they open the invoice that follows.
Free plan: 3 proposals and 3 invoices sent a month, no credit card. Solo is $19/mo for up to 3 people.
Late payment fees, answered.
Can I add a late fee to any invoice?
Generally only if the client agreed to it before the work started, in the contract or the proposal they signed. A fee that first appears on an overdue invoice is hard to enforce and easy for the client to dispute. Put the rate and any flat fee in writing up front.
Make a freelance contract with payment terms →How is the late fee worked out?
Simple interest on a 30-day month: the invoice amount, times the monthly rate, times the days late, divided by 30. A flat fee, if you set one, is added once. Interest is not charged on interest, and the result is rounded to the nearest cent.
What monthly rate is normal?
Freelance contracts often use 1% to 2% a month. Many places cap how much interest you can charge, and some limit flat fees too, so check the rules where you and your client are before you pick a number.
What is UK statutory interest on late payments?
Under the Late Payment of Commercial Debts (Interest) Act, a business can claim interest at 8% a year plus the Bank of England base rate on a late business-to-business invoice. You can't claim it if your contract sets a different interest rate. It is a yearly rate, so for a close estimate here, enter 8 plus the base rate, divided by 12, as the monthly rate. Checked on gov.uk on 9 November 2026.
When do the days late start?
From the due date on the invoice, not the date you sent it. That's why a clear due date matters: “net 30” leaves room to argue, a written date does not.
Make an invoice with a due date →Should I always charge the fee?
Not always. A late fee written into the contract gives you leverage, and many freelancers waive it the first time a good client is a few days late. A deposit before work starts protects you more than any fee after it.
How to ask for a deposit →Keep reading
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Invoice generator
Line items, tax and discount totalled as you type. Copy it or save it as a PDF, no signup.
Guide
How much deposit should a freelancer charge?
Ranges labelled as convention, measured late-payment data, wording to copy, and late-payment law by country.
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