Net 30 Sounds Simple. When Is the Invoice Actually Due?

"Net 30" is the most common payment term in business, and also one of the most quietly ambiguous. Thirty days from what?

The start date is the whole argument

Net 30 almost always means 30 calendar days, not business days. The dispute is rarely about the 30 — it's about day zero. Common candidates:

• Invoice date — the default, and what most accounting systems assume.
• Receipt of invoice — favoured by buyers, since they can't pay what they haven't received.
• Delivery or completion date — common in goods and project work.

Shift the start by a few days and the due date moves with it. On a large account, that drift is the difference between a clean ledger and a collections call.

Net 30 vs Net 15 / 60 / 90

The arithmetic is identical — just a different number of calendar days. What changes is cash-flow pressure. Net 60 and Net 90 are effectively short-term financing you're extending to your customer, so know your due dates precisely before you agree to longer terms.

Compute it, don't count it

The Net 30 Invoice Due Date calculator takes your start date and term (15, 30, 60, or 90) and returns the exact due date, so the only thing left to negotiate is which start date you both agreed to.