Invoice Due Date Calculator
Calculate when your invoice is due and track payment deadlines
Common payment terms
How it works
Payment terms define how long a customer has to pay after an invoice is issued. The due date is calculated by adding the agreed number of days to the invoice date — so an invoice dated 1 June with 30-day terms is due on 1 July. Enter your invoice date and select or enter the payment terms, and Clockr calculates the due date instantly and shows how many days remain until payment is expected.
In UK business, common payment terms include 7 days (often for small jobs or cash-flow-sensitive work), 14 days, and 30 days. Net 30 — meaning payment within 30 calendar days of the invoice date — is the most widely used standard between businesses. Longer terms such as 60 or 90 days are sometimes negotiated for larger contracts or established supplier relationships, but they extend the wait before cash arrives.
If an invoice is paid after the due date, UK law provides certain statutory rights under the Late Payment of Commercial Debts (Interest) Act 1998, including the right to claim statutory interest and a fixed compensation sum on qualifying business-to-business debts. This calculator is for date arithmetic only — it does not constitute legal advice, and you should confirm your specific rights and procedures with a qualified adviser if payment is late.
Frequently asked questions
How do I calculate an invoice due date?
Add the payment terms in days to the invoice date. For example, an invoice dated 15 March with 30-day terms is due on 14 April. Enter the invoice date in dd/mm/yyyy format, choose your payment terms (or enter a custom number of days), and the calculator shows the due date plus how many days remain or how overdue the invoice is.
What are standard payment terms in the UK?
The most common terms are 7, 14, and 30 days from the invoice date. Net 30 is the de facto standard for many B2B transactions — payment is expected within 30 calendar days. Smaller suppliers or freelancers may ask for 7 or 14 days; larger corporate buyers sometimes request 60 or 90 days. Terms should always be agreed in writing before work begins or stated clearly on the invoice.
What does “net 30” mean on an invoice?
Net 30 means the full invoice amount is due within 30 calendar days of the invoice date — not 30 working days. An invoice dated 1 January with net 30 terms is due on 31 January. “Net” indicates the full amount with no early-payment discount applied (unlike “2/10 net 30”, which offers a 2% discount if paid within 10 days).
What happens if an invoice is paid late?
Once the due date passes without payment, the invoice is overdue. You may follow up with reminders, pause further work, or escalate through your agreed dispute process. For qualifying commercial debts in the UK, statutory interest and compensation may be claimable under the Late Payment of Commercial Debts legislation. Exact steps depend on your contract, relationship, and whether the debt meets the statutory criteria.
Can I charge interest on a late invoice?
On qualifying business-to-business debts in the UK, you may be entitled to statutory simple interest at 8% above the Bank of England base rate, plus a fixed compensation amount, under the Late Payment of Commercial Debts (Interest) Act 1998. Your contract may also specify its own late-payment interest clause. This is general factual information only — not legal advice. Consult a solicitor or debt recovery specialist for your specific situation.
How do I track multiple invoice due dates?
Run the calculator for each invoice separately, noting the due date and days remaining. For ongoing tracking, use a spreadsheet or accounting software with an aged debtors report — most list outstanding invoices by due date and flag overdue items. Pair this tool with the Business Days Calculator if you need working-day counts for follow-up schedules or internal SLAs.