Statutory interest and fixed compensation on a late business invoice. Under the Late Payment of Commercial Debts (Interest) Act 1998, interest at 8% over the Bank Rate on the previous 30 June or 31 December (each half-year at its own rate), simple, by the day, from the day after the due date to the paid date (today if unpaid), plus the fixed compensation (£40 / £70 / £100 by the invoice's size). The Bank Rate is read from the Bank of England's page daily.