Week 1 / Month 1 basis: planning what your payslip could show

This page explains the Week 1 / Month 1 payroll basis in scenario terms. It is written for 2026 planning and does not guarantee a specific payslip outcome.

Open the calculator Emergency tax explainer

Why deductions can look different

Credits and bands may not be applied using year-to-date totals.
One-off payments (bonus, backpay) can amplify the effect in the period.
The annual position can be smoother than the early payslip view.

How to plan

Use annual view to budget on expected yearly net pay.
Use monthly view as a sensitivity range for short-term cashflow.
Assume reconciliation needs exact payroll basis details.

FAQ

What does “Week 1 / Month 1” mean on a payslip?

It usually means PAYE is calculated on a non-cumulative basis for the period, rather than using year-to-date totals. That can change how credits and bands are applied on early payslips.

Does Week 1 / Month 1 basis always mean emergency tax?

Not always. It is often discussed alongside emergency tax scenarios, but the exact payroll basis depends on your employment setup and Revenue notifications to payroll.

How should I estimate net pay if my payslip is on Week 1 / Month 1?

Use the calculator for planning scenarios and budgeting, but treat the result as an estimate. Payslip-level reconciliation depends on the exact payroll basis and credit allocation.

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