UK Late Payment Interest

Estimate late-payment interest, fixed compensation and totals for one UK business-to-business invoice in GBP. Submit an amount and invoice dates; receive one JSON result in the dataset and the key-value store's OUTPUT record.

What it does and who it is for

For credit controllers, bookkeepers, freelancers and AI agents checking what a late business invoice may be worth. The calculation uses simple interest at 8 percentage points above the applicable Bank of England reference rate. 1, 3 Fixed compensation is £40 for debts below £1,000, £70 from £1,000 to £9,999.99, and £100 from £10,000. 2

Not legal advice. The Actor estimates amounts; it does not determine eligibility or review contracts. GOV.UK says statutory interest cannot be claimed where a contract provides a different interest rate. 1

Quick start

Paste this input (the Actor's prefill) and click Start:

{
  "amount": 2400,
  "invoiceDate": "2026-03-01",
  "termsDays": 30,
  "paidDate": "2026-06-15",
  "businessToBusiness": true
}

Output, run on 2 October 2026. asOfDate is the run date, so it changes; the sources list of four links is omitted here.

{
  "amount": 2400,
  "currency": "GBP",
  "invoiceDate": "2026-03-01",
  "dueDate": "2026-03-31",
  "paidDate": "2026-06-15",
  "asOfDate": "2026-10-02",
  "lateFrom": "2026-04-01",
  "daysLate": 76,
  "daysLeft": 0,
  "notLate": false,
  "settled": true,
  "baseRate": 3.75,
  "annualRate": 11.75,
  "referenceDate": "2025-12-31",
  "referencePeriod": { "from": "2026-01-01", "to": "2026-06-30" },
  "estimate": false,
  "dailyInterest": 0.7726027397260274,
  "interest": 58.72,
  "compensation": 70,
  "claim": 128.72,
  "totalDue": 128.72,
  "total": null,
  "note": "Not legal advice. This is a calculation estimate; eligibility and contract terms need separate review."
}

Input fields

Field	Type	Required	Default	Meaning
amount	number	yes	none	Invoice amount in GBP, 0.01 to 1,000,000,000, at most two decimal places
invoiceDate	string	yes	none	Invoice date, YYYY-MM-DD, years 1000-9999
businessToBusiness	boolean	yes	true in the form	Must explicitly be true; other invoice types are not supported
dueDate	string	no	none	Agreed due date, YYYY-MM-DD. Do not combine with termsDays
termsDays	integer	no	none	0-999 calendar days added to invoiceDate. Do not combine with dueDate
paidDate	string	no	today (Europe/London)	Payment date or projection end date, YYYY-MM-DD

Omitting both dueDate and termsDays assumes 30 days; supply the actual due date where available. Unknown fields are rejected. Do not supply names or contact details.

Output fields

Field	Meaning
amount, currency, invoiceDate, dueDate, paidDate	Inputs as used, with the calculated due date
asOfDate	Today in Europe/London
lateFrom, daysLate, daysLeft, notLate	First day late (null if on time), days late, days until due, on-time flag
settled	true when paidDate is before today
baseRate, annualRate	Bank Rate used, and that plus 8 points, in percent
referenceDate, referencePeriod	Bank Rate observation date and the half-year it covers
estimate	true when the late period starts after the bundled rate table
dailyInterest, interest	Interest per day, and total interest, in GBP
compensation, claim	Fixed compensation; claim is always interest plus compensation
totalDue, total	Amount due; total is null when settled
note, sources	Disclaimer and source links

A paidDate before today's London date is treated as paid principal: totalDue is interest plus compensation. Today or a future date is treated as unpaid or projected: totalDue includes the principal. This is an input convention, so use dates accordingly. dailyInterest is the calculation rate, including for historical paid invoices. On-time results have zero interest and compensation. Money totals are rounded to two decimal places.

Use from code

curl -X POST "https://api.apify.com/v2/acts/landlordtools~uk-late-payment-interest/run-sync-get-dataset-items?token=YOUR_API_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"amount": 2400, "invoiceDate": "2026-03-01", "termsDays": 30, "paidDate": "2026-06-15", "businessToBusiness": true}'

import { ApifyClient } from 'apify-client';

const client = new ApifyClient({ token: 'YOUR_API_TOKEN' });
const run = await client.actor('landlordtools/uk-late-payment-interest').call({
  amount: 2400, invoiceDate: '2026-03-01', termsDays: 30,
  paidDate: '2026-06-15', businessToBusiness: true,
});
const { items } = await client.dataset(run.defaultDatasetId).listItems();
console.log(items[0].claim);

Use with AI agents

AI agents can call this Actor through Apify's MCP server (https://mcp.apify.com). Example prompt: "How much late-payment interest and compensation applies to a £2,400 business invoice dated 1 March 2026 on 30-day terms, paid on 15 June 2026?"

Reference rates and limits

The reference rate is selected from the half-year containing the first day late and retained throughout that calculation. The January-June reference uses Bank Rate on the preceding 31 December; July-December uses Bank Rate on 30 June. 3 Bank Rate history supplies the underlying observations. 4

Rates must be updated each 1 January and 1 July. The maintainer must add the next half-year row to reference-rates.json using the corresponding reference date, then run the tests. Updates are manual; the Actor does not fetch live rates. 3, 4

The bundled table covers first-late dates from 1 January 2020 through 31 December 2026. Earlier late debts are rejected. Later first-late dates reuse the final row and return estimate: true with a warning. A payment date beyond table coverage alone does not change the reference rate or set that flag.

One invoice per run. Partial payments, multiple invoices, contract-specific interest and additional recovery costs are outside the model.

Pricing

Pay per event: $0.01 per calculation result, plus Apify's tiny per-run start fee ($0.00005). See the Pricing tab for the current price.

Related Actors

• UK Business Deadlines: company and tax deadlines from a date.
• UK Working Days: working days and CPR 2.8 time limits.
• UK Renters' Rights Dates: rent increase and pet request dates.
• England PRS Registration Deadline: PRS registration dates.

Sources

1. GOV.UK: Interest on late commercial payments. Accessed 2 October 2026.
2. GOV.UK: Claim debt recovery costs. Accessed 2 October 2026.
3. GOV.UK: A users guide to the recast Late Payment Directive, pages 7–8. Accessed 2 October 2026.
4. Bank of England: Bank Rate history. Accessed 2 October 2026.