National Insurance on your payslip
National Insurance is not the same as Income Tax. It has its own thresholds, rates and category rules, and for employees it is normally worked out from earnings in each pay period.
The standard 2026/27 employee rates
For most employees using Category A, Class 1 employee NI is 8% on earnings between £242 and £967 a week, or £1,048 and £4,189 a month. Earnings above the upper limit are charged at 2%.
Why NI can change from one payslip to another
Because employee NI is normally assessed by earnings period, overtime, bonuses and other irregular pay can change the deduction for that particular period even when annual salary has not changed.
Your NI category matters
Category A is the standard category for many employees, but other category letters can produce different deductions. A simple salary estimate may therefore differ from payroll if you are not in the standard category.
Two jobs can behave differently
National Insurance is generally assessed separately for each employment rather than simply combining annual salaries. Special rules can apply in some circumstances, including deferment.
How to sense-check NI
Start with the pay frequency and NI-able earnings for that payslip. Compare the deduction with a period-based estimate, then check your NI category or ask payroll if the result still looks unexpected.
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