What overdue invoices actually cost you, then exactly what you can recover: statutory interest at BoE base rate + 8% under the 1998 Act — the Late Payment of Commercial Debts (Interest) Act 1998 (as amended by the 2002 Regulations) — plus £40 / £70 / £100 fixed compensation per overdue invoice under the 2002 Regulations. Everything recalculates as you type.