Late Fee Calculator
Calculate exactly how much you're owed when a client pays late.
Invoice & payment terms
Adjust the details below to update your estimate.
Your outstanding amount
Updates as you edit your inputs.
Use only a fee agreed in advance. Limits and enforceability vary by jurisdiction; this estimate is not legal advice.
Guide & practical tipsHow to use this tool well, limits, and common questions
Estimate a daily late fee on an overdue invoice using terms that were agreed before the payment became late. The result is a calculation aid, not a determination that a fee is legally enforceable.
How to use it
- 1
Enter the original invoice amount and due date
Put in the full invoice value and the date payment was due. The calculator uses the gap between the due date and today to work out how long the invoice has been overdue.
- 2
Enter the agreed daily rate and grace period
Use the daily percentage written in your contract or invoice terms. Add any agreed grace period before the fee begins to accrue.
- 3
Review the estimate
The calculator shows the days counted, fee amount, total outstanding, and annual equivalent so you can sanity-check the rate before contacting the client.
Tips that make a difference
- Specify your late fee policy in every contract and on every invoice before work begins. You cannot add a penalty retroactively if it was never agreed to.
- Check the rate against the rules that apply to both parties. Interest and penalty limits vary by jurisdiction and type of transaction.
- Send a payment reminder at 1 day overdue, not 30. The longer you wait, the harder the conversation becomes.
- Use the annual equivalent shown by the calculator to spot a daily percentage that becomes unexpectedly large over time.
Frequently asked questions
Can I legally charge a late fee?
It depends on the contract, notice given, local law, and type of transaction. A fee that was not disclosed and agreed in advance may be difficult or impossible to enforce. Check the rules that apply to your situation.
What percentage should I enter?
Enter the daily rate already agreed with the client. If your terms use a monthly or annual rate, convert it carefully or obtain professional advice rather than guessing.
What if my client refuses to pay the late fee?
Start by referencing the written term and sending a factual payment reminder. For a disputed or substantial amount, obtain advice appropriate to your jurisdiction before taking collection or court action.
Should I waive the late fee to keep a good client?
That is a relationship call only you can make. One option is to offer a one-time waiver in exchange for payment within 48 hours. Make clear that it is a goodwill gesture, not a precedent, and that future late payments will incur the full penalty.