Payment clauses in business contracts

A payment clause needs to explain when an invoice can be issued and when the debt becomes due. Those are separate events. A clause linked to undefined customer approval can create a much longer wait than the headline credit period suggests. Review the whole payment process before offering credit.

Distinguish a genuine invoice query from a right to withhold every payment. Ask whether disputed and undisputed amounts are treated separately, whether set-off is permitted and which supporting documents are mandatory. Check the applicable late payment framework rather than assuming that silence removes statutory rights. ^[1]

Define the event that permits invoicing

State whether invoices follow delivery, completion of a milestone, acceptance or a regular billing date. If the customer must supply a purchase order, explain when it will do so and how missing administrative information is handled. A supplier should not discover after delivery that an internal customer process prevents an invoice from entering the payment system.

For milestone work, describe the deliverable and evidence supporting the invoice. Avoid a circular arrangement in which payment waits for approval but approval has no deadline or criteria. Agree a practical review process, including how a genuine defect is raised and whether it affects the entire invoice or only the relevant portion.

Make the due date calculable

Specify what starts the payment period and how invoice receipt is established. Distinguish calendar days, business days and month-end conventions where relevant. Both finance teams should be able to calculate the same date from the clause. If they cannot, clarify the wording before relying on it in a cash-flow forecast.

Check the applicable statutory late-payment framework alongside the negotiated terms. Business and public-authority arrangements can have different rules, and unusually long terms need careful assessment. ^[1] Do not assume that a contract with no interest clause removes every statutory entitlement, or that adding a rate settles all questions about enforceability and recovery.

Deal with disputed amounts expressly

Set a process for identifying the invoice, amount and reason for a query. Ask whether the undisputed portion remains payable and whether set-off is permitted. A broad right to withhold all payments for any alleged issue can create exposure far beyond the particular defect. Consider how the supplier can continue work while a limited dispute is investigated.

Keep payment disputes separate from ordinary account administration. A missing reference number may need correction without justifying an indefinite delay. Equally, a valid invoice should not be treated as proof that disputed work was delivered correctly. The contract needs a route that allows both parties to examine evidence and reach a clear outcome.

Price the extras and the consequences of delay

Explain VAT treatment, expenses, deposits, retentions and currency where applicable. State whether expenses need prior approval and what evidence accompanies them. For cross-border payments, consider bank charges and exchange assumptions. These details can change the amount actually received even where the headline service fee is agreed.

Review suspension and termination rights for non-payment alongside interest and debt recovery. A supplier of a critical service may need a notice period before suspension; the customer needs to understand the operational consequence of a missed payment. Do not suspend simply because the team is frustrated without checking the contractual and legal position.

Test the clause with both finance teams

Walk through an invoice delivered near month end, a partly disputed milestone and an approved additional expense. Record the dates and amounts each team expects. Differences reveal drafting or process gaps before they become a collection dispute. Use clearly labelled illustrative figures rather than presenting a scenario as a guaranteed legal result.

Where payment terms are changed, obtain the required authority and signing arrangement for the amendment. Company execution formalities may matter to the document used. ^[2] Keep the approved change with the agreement and update billing instructions. Read Contract variations and written approval for variations. Business terms and conditions review can help review the payment mechanism with the scope, acceptance and remedies provisions that affect when money is actually due.

Keep invoice evidence connected to delivery

Give each milestone invoice a reference to the deliverable and approval evidence required by the contract. Where an invoice is corrected, retain the original and explain the change rather than issuing several unrelated versions with different due dates. The account record should show what was supplied, what was invoiced, what was disputed and what was paid. This is particularly helpful when a customer changes its finance contact: the new reviewer can assess the balance from the agreed process instead of restarting the entire approval because the original project manager is unavailable or no longer remembers the detail.

Illustrative scenario

A consultancy agrees payment thirty days after an approved invoice. The customer only approves invoices at a monthly meeting, so the practical delay can be much longer. The parties clarify when the invoice is received, what constitutes a valid query and when the undisputed amount is payable. That removes an avoidable cash flow uncertainty.

Preparation checklist

• Write down the event that starts the payment clock.
• Confirm purchase order requirements before delivering the work.
• Check deposits, milestones, VAT and approved expenses separately.
• Keep evidence of invoice delivery and any dispute notification.