Late Payment Interest Calculator
Calculate statutory late payment interest on overdue invoices. Generate a formal demand letter instantly.
Late Payment Interest Calculator
Calculate statutory interest on overdue invoices
Invoice Details
When was the payment supposed to be made?
Cal. Civ. Proc. Code § 685.010 — 10% per annum for commercial debts
Cost of reminder letters, collection agency fees, admin time.
Your results will appear here
Fill in the details on the left and hit calculate to see your numbers.
About the Late Payment Interest Calculator
Calculate statutory interest on overdue invoices. Generate a formal demand letter instantly.
What you can do with it
- US, UK, EU jurisdictions
- Auto-generated demand letter
- Interest calculation
- Debt recovery tips
Frequently asked questions
Can I charge interest on a late invoice?
In most jurisdictions, yes. In the UK, the Late Payment of Commercial Debts (Interest) Act 1998 lets you charge 3% above the Bank of England base rate (or whatever your contract states). In the EU, Directive 2011/7 provides statutory rates per country. In the US, it depends on your contract and state law — a late-fee clause of 1–1.5% per month is common and enforceable.
What should a late payment demand letter include?
The invoice number and original due date, days overdue, the amount due plus any contractually permitted interest, a clear payment deadline (7–14 days is standard), acceptable payment methods, and a calm statement of the next step if payment doesn't arrive (suspension of work, collections referral, or small-claims filing). This tool generates a letter with all of that filled in.
How do I prevent late payments in the first place?
Deposit before starting work (30–50% is standard for projects), invoice the day the work is delivered, state your due date and late-fee policy on every invoice, and chase fast — a polite nudge at day 1 and day 7 recovers most invoices without a formal demand letter.
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Invoice Best Practices That Get You Paid FasterLate Payment Interest Calculator: Common Questions
Can I charge interest on a late invoice?
In most jurisdictions, yes. In the UK, the Late Payment of Commercial Debts (Interest) Act 1998 lets you charge 3% above the Bank of England base rate (or whatever your contract states). In the EU, Directive 2011/7 provides statutory rates per country. In the US, it depends on your contract and state law — a late-fee clause of 1–1.5% per month is common and enforceable.
What should a late payment demand letter include?
The invoice number and original due date, days overdue, the amount due plus any contractually permitted interest, a clear payment deadline (7–14 days is standard), acceptable payment methods, and a calm statement of the next step if payment doesn't arrive (suspension of work, collections referral, or small-claims filing). This tool generates a letter with all of that filled in.
How do I prevent late payments in the first place?
Deposit before starting work (30–50% is standard for projects), invoice the day the work is delivered, state your due date and late-fee policy on every invoice, and chase fast — a polite nudge at day 1 and day 7 recovers most invoices without a formal demand letter.
Explore the rest of the toolkit in the free tools directory, or read practical guides in the blog.