Know what your overdue invoice may be worth.
Check whether UK late-payment rules may apply, calculate potential interest and compensation, and turn the result into a practical recovery plan.
Free late-payment check
Answer three eligibility questions, then enter the invoice amount and due date.
Eligibility
Check whether this calculator may apply
Is the unpaid invoice for goods or services supplied to another business?
Is the invoice disputed?
Does your contract already specify its own late-payment interest?
Invoice details
Tell us about the unpaid invoice
Enter the date your customer agreed to pay.
Complete the eligibility questions above before calculating.
What stays free
The calculator and calculation result are free.
No signup is required to check eligibility, calculate the estimate, view the breakdown or copy the calculation. The optional Recovery Pack costs £1.99 and adds recovery-planning tools and documents; you do not need to buy it to use the calculator.
Example output
See how the estimate is broken down.
For a £2,500 qualifying commercial debt that is 45 days overdue, an 11.75% annual statutory rate would produce about £36.22 in simple interest, plus the £70 fixed recovery sum — a potential additional amount of about £106.22. Your result depends on the dates, rate period and eligibility of your own debt.
What this calculator covers
LatePay Kit is a basic estimator for potentially qualifying UK commercial debts where you know the agreed payment due date and there is no separate contractual late-payment interest rate. It does not decide disputes, determine whether a complex contract qualifies, calculate a fallback due date when no payment date was agreed, or adjust the principal for partial payments. Enter the unpaid amount you want assessed and check current official guidance before taking formal action.
Official references: GOV.UK late commercial payments guidance and Late Payment of Commercial Debts (Interest) Act 1998.
Learn before you escalate
Understand UK late-payment rules, then decide what to do next.
The calculator stays focused on your invoice. Detailed explanations live in separate guides so you can understand interest, compensation and practical recovery steps without cluttering the calculation.
Late-payment interest
How statutory interest is calculated for potentially eligible commercial debts.
Read guide →
Recovery compensation
How the £40, £70 and £100 fixed recovery sums work.
Read guide →
Recovering an unpaid invoice
A practical UK sequence for chasing payment, preserving evidence and escalating proportionately.
Read guide →
Late Payment Act
The UK legal framework behind statutory interest and recovery compensation.
Read guide →