30 day
payment terms

Thirty days is the default rhythm of UK business: long enough for a customer's approval and payment run, short enough to keep a small business's cash flowing. It is also the period the law uses when no one agreed anything. Here is how the 30 days are counted, and what changes when they run out.

What net 30 means

"Net 30" or "payment within 30 days" means the invoice must be paid within 30 calendar days of the invoice date. An invoice dated 1 March is due by 31 March. Weekends and bank holidays count, unless your terms say working days.

Always write the resulting date on the invoice: "Payment due within 30 days, by 31 March". It saves the customer the arithmetic and removes any doubt about when the payment became late. The invoice due date calculator works it out.

30 days end of month is longer

"30 days end of month", often written "30 days EOM", counts 30 days from the last day of the month the invoice is dated in. An invoice dated 15 January is due 30 days after 31 January, which is 2 March in a year when February has 28 days. An invoice dated 1 January is due on the same day as one dated 31 January, so EOM terms can stretch payment to nearly two months. Check which one a customer means before you agree.

When no terms were agreed

If you never agreed a payment date with a business customer, the law fills the gap: payment is late 30 days after the customer gets the invoice or you deliver the goods or provide the service, whichever is later. So the 30 days start from receipt or delivery, not from the date you typed on the invoice. Send invoices promptly and keep evidence of when they were sent.

How 30 days compares with the limits

Thirty days sits well inside what the law expects. An agreed payment date should usually be within 60 days for a business customer, and within 30 days for a public authority. If a large customer asks for 60 or 90 days, that is a commercial choice for you to accept or refuse; beyond 60 days it must be fair to both businesses.

Day 31: the payment is late

The day after the due date, the payment is late. With a business customer you can then claim statutory interest, 8% a year over the Bank of England base rate, plus fixed compensation of £40, £70 or £100 depending on the size of the debt. The late payment interest calculator shows the figures for your invoice, and charging interest on late payments explains how to claim it.

Before that, a reminder often does the job. A polite note the day after the due date, then firmer steps if nothing arrives, are set out in how to chase an unpaid invoice.

Is 30 days right for you?

For a new customer, a large order or a small business with tight cash flow, 30 days can be a long wait. Consider 14 days for individuals and small businesses, a deposit for new customers, and stage payments for long projects. Keep 30 days for established business customers whose payment runs work on a monthly cycle. Whatever you choose, agree it before you start and put it in writing.

A quick example

A plumber finishes a job for a letting agency on 10 June and invoices the same day on net 30. The payment is due by 10 July. If it arrives on 25 July, it is 15 days late, and the plumber can add statutory interest for those 15 days plus the fixed compensation.

Net 30 and 30 days EOM compared

Dates in a year when February has 28 days. The invoice due date calculator works out any combination.

Why 30 days became the standard

Most businesses pay suppliers in batches, a weekly or monthly payment run, after invoices have been checked and approved. Thirty days gives time for an invoice to arrive, be matched to an order, be approved and reach the next run. It is also the period the law uses as its default for business customers, and the usual limit for public authorities. That makes it the term most customers expect and fewest will question.

Making net 30 work for a small business

Thirty days is a long time to wait if you have already paid for materials and your own time. Four ways to make it work:

1. Invoice the day the work ends. Every day you wait is added to the 30.
2. Put the due date on the invoice. "Due by 14 October" is harder to miss than "net 30".
3. Remind before the date. A short note a few days before the due date prevents most late payments.
4. Use shorter terms where you can. Households and small businesses can usually pay in 7 or 14 days; see invoice payment terms.

When a customer asks for longer

Some large customers ask suppliers to accept 60 days or more. Up to 60 days is within what the law expects for business customers; beyond 60 days, the agreed period must be fair to both businesses. You can negotiate: accept longer terms in exchange for a higher price, a deposit, or monthly invoicing so that no single invoice is large. If cash flow is the worry, invoice finance and invoice factoring let you borrow against or sell unpaid invoices, at a cost.

Late payment on net 30: the figures

Once a net 30 invoice is late, a business customer can owe statutory interest at 8% a year over the Bank of England base rate on the relevant reference date, charged daily, plus fixed compensation of £40, £70 or £100. The chart above shows how interest builds on a typical invoice. It is not a fortune on one invoice, but across a year of late payers it adds up, and telling customers you will claim it is often what gets them paying on day 30. The late payment interest calculator gives the exact figure for your dates, and the guide on charging interest on late payments explains how to claim.

Common questions

Does net 30 start from the invoice date or the date the customer receives it? From the invoice date, if that is what your terms say. Only where no date was agreed does the law count 30 days from receipt or delivery.

If the 30th day is a Sunday, is payment due on Monday? Not automatically. The due date is the 30th day. If your customer pays in a Monday run, agree in advance whether that counts, to avoid arguing over one day's interest.

Is 30 days end of month legal? Yes, it is an agreed term like any other. Just be aware it can add up to a month to the wait, and check the total stays within what is fair.

Can I charge a household customer interest after 30 days? Not under the Late Payment Act, which only covers business customers. You can only charge a consumer interest if the contract clearly and fairly provided for it.

Writing 30 day terms on your invoice

Three short lines do the job. Under the total, write "Payment terms: 30 days from the invoice date." Beneath it, the date that produces: "Please pay by 14 October." Then your payment details and the reference to quote, which should be the invoice number. If you intend to claim statutory interest on late payment from business customers, a fourth line can say so: "Late payments from business customers may attract statutory interest and compensation under the Late Payment of Commercial Debts (Interest) Act 1998." Put the same terms in your quote and order confirmation, so the invoice simply repeats what was already agreed. The how to write an invoice guide shows where each line goes.

If the customer pays on day 31 or later

Chase the next working day, politely and in writing, and phone if a week passes. Most late payments on 30 day terms are an invoice stuck in approval, not a refusal. If it runs on, the steps in how to chase an unpaid invoice escalate from reminders to statutory interest, then a letter before action and, as a last resort, a small claim.

Thirty days is a sensible default for business customers. Used well, with the date written down, a reminder before it and prompt chasing after it, it keeps cash moving without straining relationships. Used carelessly, it quietly becomes forty-five.