The payment timeline on an invoice is primarily a contractual matter, not a legal one. What you and your client agreed to — in writing, before the work started — is what counts.
What “legally” means for invoice payment
There is a common misconception that some government rule dictates exactly how many days a client has to pay an invoice. In practice, payment terms are a contract matter. The law steps in when someone breaks those terms — not to dictate what the terms should be.
If your invoice says “net 30” and your client agreed to those terms before the project started, then they legally have 30 days to pay. After that, they are in breach, and you have legal remedies available. If you never specified terms, the default in most US states and UK commercial law is 30 days.
Common payment terms and what they mean
- Net 15: Payment due within 15 days. Common for small projects, digital services, or clients with reliable payment histories.
- Net 30: The most widely used commercial standard. Thirty days from the invoice date.
- Net 60: Used by larger companies with formal AP processes. Sixty days from invoice date.
- Due on receipt: Payment expected immediately upon invoice receipt. Common for deposits and final milestones on small projects.
As a freelancer, you can set whatever terms you prefer. Many experienced freelancers use net 15 as the default because it normalizes faster payment without significant client pushback.
Most clients never question net 15 terms — they pay when they get the invoice. You only hear complaints from clients who were planning to delay anyway.
What the UK law says
The UK has the most specific statutory framework for invoice payment. Under the Late Payment of Commercial Debts Act, business-to-business invoices have a statutory default of 30 days, after which statutory interest at 8% above the Bank of England base rate applies automatically. Freelancers operating under UK law can claim this interest without a contract clause specifying it.
What US law says
The US has no federal equivalent, but most states recognize “net 30” as the commercial default. More importantly, state contract law governs enforcement. If you have a signed agreement with clear payment terms, any competent court will enforce those terms — including late fees, if your contract specified them.
How to set enforceable payment terms
For terms to be legally enforceable, they need to be agreed upon before the work starts. The clearest way to do this: include payment terms in your contract, repeat them on your invoice, and get the contract signed. Using Waco, your invoices display payment terms prominently, and you can see when the client opened and reviewed the invoice — a timestamped record that supports your position if payment is disputed.
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