Late payment interest

Under the Late Payment of Commercial Debts (Interest) Act 1998 you can add interest and a fixed sum to a late invoice when both you and your client are businesses. It applies across the UK. This is general information, not legal advice.

The interest

8% a year above the Bank of England base rate. The base rate used is the one on 31 December or 30 June before the invoice fell due, and it stays the same until the invoice is paid. It's simple interest, worked out by the day.

The fixed sum

Amount owed	You can add
Under £1,000	£40
£1,000 to £9,999.99	£70
£10,000 or more	£100

Switching it on

It's off until you switch it on in Settings > The law. You'll need your business address, because it goes on final notices and letters. Leave it off if your contract sets its own late-payment terms.

PaidStraight only adds interest when the client is a business, the invoice is in pounds, and the setting is on. It's only ever mentioned in the final notice and later steps, never in a friendly reminder.