Free UK Late Payment Calculator

Still waiting to get paid? They owe you more than you think.

UK law lets you charge 11.75% interest + up to £100 compensation on every overdue B2B invoice. Most people don't claim it. You should.

Used by freelancers, contractors, and small businesses across the UK

⚖ Based on UK statute law
✓ Free — no sign-up
⏱ Results in 10 seconds

Enter your invoice details

We'll calculate the statutory interest and compensation you're legally entitled to.

The date payment was due (usually 30 days after invoice)

Your statutory rights on late payments

11.75%
Annual interest rate
8% + BoE base rate (3.75%)
£40–£100
Fixed compensation
Per invoice, by statute
6 years
Time to claim
Limitation Act 1980
You don't need special contract terms. The Late Payment of Commercial Debts (Interest) Act 1998 gives every UK business the automatic right to charge interest and claim compensation on overdue B2B invoices.

The 4-step process to recover your money

Most late payments aren't malicious — they're disorganised. A structured approach recovers the majority without court.

1

Friendly Reminder

Assume it's an oversight. A polite nudge resolves most cases.

2

Firm Follow-Up

Mention the Late Payment Act. Give a clear 7-day deadline.

3

Final Warning

State the total owed including interest and compensation. Last chance.

4

Letter Before Action

Legal prerequisite before court. Most debts are paid at this stage.

Late Payment Interest Calculator: How It Works

If you're a freelancer, contractor, or small business owner in the UK, late payment isn't just frustrating — it threatens your livelihood. The average UK small business is owed over £30,000 in unpaid invoices at any given time.

The good news: UK law is firmly on your side.

The Late Payment of Commercial Debts (Interest) Act 1998

This Act gives every UK business the automatic right to charge interest and claim compensation on late B2B invoices. You don't need to have included late payment terms in your contract.

How to Calculate Late Payment Interest

Invoice amount x 11.75% / 365 x days overdue = interest owed

Example: £5,000 invoice, 60 days late: £5,000 x 0.1175 / 365 x 60 = £96.58 interest + £70 compensation = £166.58 on top of the original.

What Is a Letter Before Action?

A Letter Before Action (LBA) is a formal legal document notifying a debtor you intend to take court action. Under the Pre-Action Protocol for Debt Claims, you must send an LBA and allow 30 days before filing a county court claim. Most debts are paid at this stage.

Frequently Asked Questions

How much interest can I charge on a late invoice in the UK? ▼
Under the Late Payment of Commercial Debts (Interest) Act 1998, you can charge statutory interest at 8% above the Bank of England base rate. As of 2026, the base rate is 3.75%, making the total rate 11.75% per annum.
Do I need late payment terms in my contract? ▼
No. The statutory right to charge interest and claim compensation applies automatically to all B2B transactions under UK law.
What is the fixed compensation for late payment? ▼
£40 for debts up to £999.99, £70 for debts between £1,000 and £9,999.99, and £100 for debts of £10,000 or more. Per invoice, not per debtor.
How long do I have to chase an unpaid invoice? ▼
6 years from the due date under the Limitation Act 1980 (England and Wales). 5 years in Scotland.
Does this apply to sole traders and freelancers? ▼
Yes. The Act applies to all business-to-business transactions regardless of business structure.
How do I take someone to small claims court? ▼
For debts under £10,000, file through Money Claim Online (moneyclaim.gov.uk). Send a Letter Before Action first and wait 30 days. Court fees: £35-£455. No solicitor needed.

Want this running automatically across all your invoices?

Ascent Systems builds AI agents that monitor your invoices, detect late payments, calculate interest, and send escalating chase emails — automatically, 24/7. Never chase a payment manually again.

Stop letting clients hold your money

Calculate what you're legally owed and get the emails to collect it.

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