NEC vs JCT Payment Timelines Compared

NEC and JCT are the two most widely used contract families in UK construction, and their payment mechanisms work differently. If you work across both contract types, understanding the differences in assessment dates, due dates, and notice periods is essential for protecting your cashflow. This guide compares the payment timelines side by side so you can manage deadlines confidently regardless of the contract form.

Overview of Payment Mechanisms

Both NEC and JCT comply with the Construction Act, but they structure the payment cycle differently. JCT uses interim valuations at set intervals with a traditional certification process. NEC uses an assessment process driven by the project manager, with specific timescales set out in the Contract Data.

• JCT: interim certificates issued by the contract administrator at regular intervals
• NEC3/NEC4: the project manager assesses the amount due at each assessment date
• Both must comply with the Construction Act notice requirements
• The specific dates and periods are defined in the contract particulars or Contract Data
• Understanding which mechanism applies is critical for managing payment timing

JCT Payment Timeline

Under a standard JCT contract (e.g., JCT SBC 2016), the payment cycle follows a well-established pattern. The contractor submits an interim application, the contract administrator issues an Interim Certificate, and payments follow defined notice and final date periods.

• Interim Valuation Date: as stated in the Contract Particulars (e.g., monthly)
• Due Date: 7 days after the Interim Valuation Date (standard, can be varied)
• Payment Notice: within 5 days of the Due Date
• Pay Less Notice: not later than 5 days before the Final Date for Payment
• Final Date for Payment: 14 days after the Due Date (21 days total from valuation)
• These periods can be adjusted in the Contract Particulars -- always check

NEC3 Payment Timeline

Under NEC3, the project manager assesses the amount due at each assessment date. The assessment is not dependent on the contractor submitting an application, though in practice contractors submit their own assessment to support the process.

• Assessment Date: as stated in the Contract Data (e.g., every 4 weeks)
• The project manager assesses the amount due within 7 days of each assessment date
• Payment is due within 3 weeks of each assessment date
• Correction period: the project manager can correct an assessment in the next payment cycle
• Interest accrues on late payments from the date they should have been made

NEC4 Payment Timeline

NEC4 introduced changes to align more closely with the Construction Act. The payment mechanisms are clearer, and the notice requirements are more explicit than in NEC3.

• Assessment Date: as stated in Contract Data Part 1
• The project manager makes an assessment within the period stated in Contract Data
• Payment Notice: must state the amount the project manager has assessed as due
• Pay Less Notice: can be issued if the client intends to pay less than the notified sum
• Final Date for Payment: as stated in Contract Data (typically 3-4 weeks after assessment)
• NEC4 provides clearer alignment with Construction Act section 110A requirements

Key Differences at a Glance

The most important practical differences relate to who drives the assessment, the timing of key notices, and the flexibility to adjust periods within the contract. Both frameworks protect the right to payment, but the mechanics and terminology differ.

• JCT: contractor applies, contract administrator certifies; NEC: project manager assesses
• JCT uses "Interim Certificate"; NEC uses "assessment"
• JCT default due date: 7 days after valuation; NEC4: per Contract Data
• JCT final date: typically 14 days after due date; NEC4: per Contract Data
• Both require a Payment Notice and allow a Pay Less Notice
• NEC is more prescriptive about the project manager's role in the payment process
• Always read the specific contract rather than relying on generic summaries