An invoice can have every price right and still ask for your money too soon.
Your agreement with a supplier says how long you have to pay each invoice. That period is the payment term. If the agreement gives you 30 days and the invoice says 14, the invoice is wrong.
Paying 16 days early doesn't change the invoice total, so it is easy to accept. This article shows what those days are worth, with two Watchdog examples.
What 30 days are worth
Every day of credit in your agreement is a day the supplier waits for its money while you keep yours. That gives you two things.
Better liquidity. Until the due date, the money stays in your account, where it can earn interest or reduce what you borrow. The agreed payment term works like an interest-free loan from the supplier.
Less working capital tied up. Working capital is the money a business needs to run from day to day. The later you pay for what you buy, the less of your own money is tied up in it.
You can work out how much money a longer payment term frees up:
Capital freed up =Yearly purchases incl. VAT365 days× Days gained
Example: NOK 10,000,000 a year, 30 days instead of 14
- NOK 10,000,000 ÷ 365
- NOK 27,397 a day
- NOK 27,397 × 16 days
- NOK 438,356
With NOK 10 million a year in purchases, 30 days instead of 14 leaves about NOK 438,000 more in your account on average. At an illustrative interest rate of 4.5%, that is worth about NOK 19,700 a year.1
It works the other way too. When a supplier's invoices are due sooner than the agreement says, that money moves from your account to theirs.
Two Watchdog examples
Power bills due 15 days early
The case
A large Norwegian group buys electricity for its sites from one supplier.
What the agreement said
The group has 45 days from the invoice date to pay.
What was invoiced
In July and August 2026, the supplier sent 98 invoices, about NOK 2.57 million each month including VAT. Every one was due after 30 days. At that purchasing volume, paying 15 days early would tie up about NOK 1.24 million on average.
- Invoiced
- NOK 5,141,097
- Days early
- 15
- Capital tied up
- NOK 1,243,814
Tyre invoices due in 10 days instead of 30
The case
A small Norwegian company buys tyres from one supplier.
What the agreement said
"Net 30 days": the full amount is due 30 days after the invoice date.
What was invoiced
In 2025, all 289 of the supplier's invoices were due after 10 days. A typical invoice was about NOK 4,000, so each one looked harmless. Together they came to NOK 1.6 million, all due 20 days early.
- Invoiced
- NOK 1,640,342
- Days early
- 20
- Capital tied up
- NOK 107,212
What happened next
The company raised the payment terms with the supplier. Since June 2026, the supplier's invoices have been due after 30 days.
Our recommendation
Payment terms are worth negotiating like any other part of the price.2 Before you sign, run the calculation above with your own purchases from that supplier, so you know what each extra day is worth.
Once the terms are agreed, make sure the invoices follow them. When an invoice shows shorter terms, tell the supplier.