National Insurance Calculator 2026/27

In employee mode, the first figure is the National Insurance deducted from the employee's pay for the period entered, and the second is what the employer pays on top of that same pay. The two are separate charges: employer National Insurance is a cost to the business and is never deducted from the employee.

In self-employed mode the headline figure is the total National Insurance for the year, with the profit remaining shown before Income Tax. The effective rate is total National Insurance divided by pay or profit, so it is always lower than the headline band rate.

• Annual, monthly and weekly views present the same calculation over a different period.
• The band notes underneath the result show which thresholds and rates were applied.

National Insurance is a contribution towards the State Pension and certain benefits. Employees pay Class 1 contributions through PAYE, employers pay their own secondary Class 1 contributions on the same earnings, and self-employed people pay Class 4 on their profits.

Like Income Tax, National Insurance is charged in slices. Nothing is charged on earnings below the relevant threshold, a main rate applies to the middle slice, and a lower rate applies above the upper limit. Unlike Income Tax, employee National Insurance is normally worked out on each pay period separately rather than cumulatively across the year, which is why a bonus month can look unusually expensive.

• Employee Class 1 for category A: nothing to £12,570 a year, 8% to £50,270, then 2%.
• Employer Class 1: 15% on earnings above the £5,000 secondary threshold.
• Self-employed Class 4: nothing to £12,570, 6% to £50,270, then 2%.

All rates and thresholds come from a single versioned data set, national-insurance-2026-27, reviewed against the GOV.UK sources listed below on 20 September 2026. Nothing is fetched from GOV.UK when you use the calculator: the figures are static, dated and shown with the tax year they belong to.

The Class 1 thresholds, category rates and employer reliefs are shared with the payroll calculator, so both tools always agree. The engine is pure TypeScript running in your browser, keeps full precision internally and rounds only for display. Unit tests cover the published boundaries, every category letter group, the relief thresholds and the self-employed bands.

Thresholds are published annually, weekly and monthly. The calculator uses the set that matches the pay frequency you choose.

• Lower Earnings Limit: £6,708 a year (£559 monthly, £129 weekly).
• Primary Threshold: £12,570 a year (£1,048 monthly, £242 weekly).
• Upper Earnings Limit: £50,270 a year (£4,189 monthly, £967 weekly).
• Main rate 8% for categories A, F, H, M, N and V; 1.85% for B, E and I; 2% for D, J, L and Z; nil for C, K and S.
• 2% applies above the Upper Earnings Limit for all categories that pay contributions.

Employers pay secondary Class 1 contributions of 15% on each employee's earnings above the secondary threshold of £5,000 a year. This is a business cost on top of gross pay and is not taken from the employee.

Some categories carry a zero rate up to a higher secondary threshold: £50,270 for under-21s, qualifying apprentices under 25 and eligible veterans, and £25,000 for qualifying Freeport and Investment Zone employees. Above those thresholds the normal 15% applies.

Class 4 is charged on taxable profit and collected through Self Assessment alongside Income Tax. Nothing is due on profit up to the £12,570 Lower Profits Limit, 6% applies between that and the £50,270 Upper Profits Limit, and 2% applies above it.

Class 2 is no longer a compulsory flat weekly charge for self-employed people with profits at or above the Small Profits Threshold of £7,105. Those profits are treated as though Class 2 has been paid, so the contribution record is protected without a payment.

Below £7,105, Class 2 can still be paid voluntarily at £3.65 a week — about £189.80 for a full year — if you want the year to count towards the State Pension and certain benefits. The calculator only adds this amount when you tick the voluntary option and profits are below the threshold.

Your category letter tells payroll which rates apply. Category A covers most employees. Others cover employees over State Pension age, under-21s, apprentices under 25, veterans in their first civilian job, deferment where National Insurance is already paid in another job, reduced-rate elections, and Freeport or Investment Zone employees.