1,000.00 × 1.5% × 1 month = 15.00
Inputs
Numbers update live as you type.
Invoice
Late-fee rate
Match the rate to what's in your contract or invoice T&Cs.
Charges 1.5% for every started month past due (day 1-30 = 1 month, day 31 = 2 months, etc.).
Reminder email (optional)
Fill these in to personalise the copy-ready email below.
Copy-ready reminder email
Polite, professional, and pre-filled with your numbers. Paste into Gmail, Outlook, or any CRM.
Hi [Client name], This is a friendly reminder that invoice [#] for $1,000.00, due on April 7, 2026, is now 30 days overdue. As outlined in our agreement, a late fee of 1.5% per month (or part thereof) applies — 1 month of accrual, which works out to $15.00 on this invoice. The total amount now due is $1,015.00. Could you let me know when payment will be sent? If there's anything I can help resolve, please reply and I'll get back to you the same day. Thanks, [Your name]
Want this sent automatically when an invoice goes overdue? Create a free account and set a late-fee policy per client.
The three rate models
Pick the one that matches your contract. If you don't have a written rate, 1.5% per month is the freelance industry default and what most US small claims courts recognise.
Flat one-time fee
A single fee that triggers the moment the invoice goes overdue, regardless of how many days late. Best for low-value invoices where compounding interest doesn't make sense.
$50 late fee on a $500 invoice
Per month (or part thereof)
Most common in US freelance contracts. Day 1-30 = 1 month's fee, day 31 = 2 months', etc. Compounds quickly so use it sparingly on long-overdue accounts.
1.5% × $1,000 × 2 months = $30 on day 35
Annual rate (prorated daily)
How EU/UK statutory interest works. Quote a yearly rate, charge for actual days overdue. The fairest model when you want a smooth accrual rather than month-end jumps.
13% × $2,000 × 45 days ÷ 365 = $32.05
Stop calculating these manually
Set a late-fee policy on each client once, and Invoice Tracker will automatically create a draft late-fee invoice the moment an overdue invoice crosses the grace-period threshold. The reminder email goes out automatically too. Same calculator, applied for you in the background — still free.
Frequently asked
What's a reasonable late fee for freelance invoices?
1.5% per month (or part thereof) is the most common US freelance convention — it works out to ~18% APR, which courts have generally treated as enforceable. Outside the US, statutory rates apply: the UK Late Payment of Commercial Debts Act sets it at the Bank of England base rate + 8% (currently around 13% APR) plus a fixed compensation amount; the EU Late Payment Directive uses the ECB main refinancing rate + 8 percentage points plus a €40 minimum. Whatever rate you choose, it must be in your contract or invoice T&Cs to be enforceable.
How does this calculator work?
Enter the original invoice amount, the due date, your late-fee rate, and how it applies (one-time flat, per month, or per year prorated daily). The calculator shows you days overdue, the computed fee with the formula breakdown, and the new total due. Everything runs in your browser — your invoice data never touches our servers.
What's the difference between flat, monthly, and annual rate modes?
Flat = a one-time fee that applies the moment the invoice goes overdue, regardless of how many days late (e.g. '$50 late fee'). Monthly = the fee accrues each calendar month or part thereof — day 31 charges for 2 months ('1.5% per month' contracts). Annual = the rate is yearly but accrues per actual day overdue, the way EU/UK statutory interest works ('13% per year, prorated daily').
Is the reminder email template legally enforceable?
The email itself is just a polite reminder — it's not a legal demand. The fee is enforceable only if your original contract or invoice T&Cs disclosed the rate before the work was done. For first-time chasing, the email template here is intentionally non-confrontational; if you escalate to a formal demand letter (Letter Before Action in the UK, demand letter in the US), use a lawyer-reviewed template, not this one.
Can I automate this so I don't have to chase manually?
Yes — that's exactly what the free Invoice Tracker account does. Set late_fee_pct on each client (e.g. 1.5%), and our cron creates a draft late-fee invoice the moment one of their invoices crosses the grace-period threshold. The reminder email goes out automatically too. The calculator on this page is the manual version of that workflow.
This calculator is for informational use only and is not legal or financial advice. Late-fee enforceability depends on your jurisdiction and whether the rate was disclosed in your contract or invoice terms before the work was completed. For jurisdiction-specific guidance, consult a lawyer in your region.