Methodology · Late Payment Calculator

Computing statutory
interest.

A full account of the Late Payment of Commercial Debts (Interest) Act 1998, the Bank of England base rate plus 8 percentage points, the tiered fixed-sum compensation, and the conditions under which the entitlement crystallises.

  • Late Payment Act 1998
  • BoE Base + 8pp
  • £40 / £70 / £100 Tiers
  • May 2026 Update

1. The source statute

The locked wording: Late Payment of Commercial Debts (Interest) Act 1998: statutory interest is Bank of England base rate + 8 percentage points; compensation tiered at £40 / £70 / £100 by invoice value. The Act provides a statutory entitlement to interest on commercial debts paid late.

2. When the entitlement crystallises

The entitlement applies to "commercial debts" under B2B and B2G contracts. The clock starts on the day after the agreed payment date and stops when the debt is paid in full.

3. The interest rate

Statutory interest is the Bank of England official base rate prevailing on the relevant reference date (30 June or 31 December), plus 8 percentage points. The Calculator applies the correct reference rate for the period.

4. The fixed-sum compensation tiers

  • £40 for debts under £1,000.
  • £70 for debts of £1,000 to £9,999.99.
  • £100 for debts of £10,000 and over.

5. The Calculator's output

The Calculator produces a one-page itemised statement showing interest accrual and fixed-sum compensation, suitable for enclosing with a formal demand letter.

6. Edge cases

The Act does not apply to consumer debts (B2C) or where the contract excludes the Act under section 8 controls. The Calculator flags these non-applicable scenarios.

7. The waive-or-charge decision

It is a statutory entitlement. You can choose to charge or waive to preserve relationships, but the entitlement remains yours by law until waived.

8. What the Calculator does not do

It does not chase the debt or draft the letter before action. Those capabilities live in CrowCash, which adds AI likelihood scoring and audit logs.

9. References

  • Late Payment of Commercial Debts (Interest) Act 1998.
  • Late Payment of Commercial Debts Regulations 2013.
  • Bank of England, Bank Rate historic data.

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The 1998 Act is the statutory floor for recovery.