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Finance Calc Kit
Tax

National Insurance UK Calculator

Calculate your UK National Insurance contributions for 2025/26. Free online NI calculator for employed and self-employed with Class 1, 2, and 4 contributions.

Income details

£

National Insurance due

£2,834.40

Tax year 2025/26

Class 1 rates

  • 0% on the first £12,570.00
  • 8% on £12,570.00 to £50,270.00
  • 2% above £50,270.00
On annual income of £48,000.00, estimated National Insurance is £2,834.40 for tax year 2025/26.
Thresholds and rates reflect UK National Insurance guidance for tax year 2025/26. NI rules can differ from Income Tax allowances, and employer Class 1 secondary contributions are not included in this employee and self-employed estimate.
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How UK National Insurance works

National Insurance (NI) is a UK payroll and profits tax that funds the NHS, state pension, and other social security benefits. The amount you pay depends on whether you are employed or self-employed, your annual earnings, and the tax year. This calculator estimates employee Class 1 and self-employed Class 2 and Class 4 contributions using thresholds for tax year 2025/26.

NI is separate from Income Tax, so planning take-home pay often means checking both. Pair this estimate with the income tax calculator for a broader view of deductions, or estimate UK capital gains on asset sales with the UK capital gains tax calculator.

Class 1 NI for employed earners

Employed workers pay Class 1 NI on earnings above the Primary Threshold (PT) of £12,570 in 2025/26. The main rate is 8% on earnings between the PT and the Upper Earnings Limit (UEL) of £50,270. Earnings above the UEL are charged at 2%.

Class 1 NI=0.08×min⁡(E,UEL)−PT)+0.02×max⁡(0,E−UEL)\text{Class 1 NI} = 0.08 \times \min(E, \text{UEL}) - \text{PT}) + 0.02 \times \max(0, E - \text{UEL})

Where E is annual earnings. If earnings are at or below £12,570, Class 1 NI is zero for this simplified employee estimate.

Class 2 and Class 4 NI for self-employed profits

Self-employed people may pay Class 2 at a flat weekly rate when annual profits reach the Small Profits Threshold (£6,845 in 2025/26), plus Class 4 on profits above the Lower Profits Limit (LPL) of £12,570. Class 4 is 6% between the LPL and Upper Profits Limit (UPL) of £50,270, then 2% above the UPL.

Class 2=52×wif profits≥SPT\text{Class 2} = 52 \times w \quad \text{if profits} \geq \text{SPT}
Class 4=0.06×(min⁡(P,UPL)−LPL)+0.02×max⁡(0,P−UPL)\text{Class 4} = 0.06 \times (\min(P, \text{UPL}) - \text{LPL}) + 0.02 \times \max(0, P - \text{UPL})

Worked example: £48,000 employed income in 2025/26

Earnings of £48,000 sit entirely between the PT and UEL. The taxable band is £48,000 minus £12,570, which equals £35,430. At 8%, Class 1 NI is £2,834.40 for the year.

Frequently asked questions

Do I pay NI if I earn less than the Personal Allowance?
NI is separate from Income Tax. For 2025/26, the Primary Threshold is also £12,570, so most employees start paying NI and Income Tax around the same earnings level. You may still have NI obligations if earnings exceed the relevant threshold even when other tax reliefs apply.
What is the difference between Class 1 and Class 4 NI?
Class 1 is paid by employees on wages above the Primary Threshold. Class 4 is paid by self-employed people on annual profits through Self Assessment. Self-employed workers may also owe Class 2 at a flat weekly rate when profits exceed the Small Profits Threshold.
How many years of NI contributions do I need for the state pension?
You generally need at least 10 qualifying years to receive any UK state pension and 35 qualifying years for the full new State Pension. You can review your NI record on GOV.UK and make voluntary Class 3 contributions to fill gaps.
Does this calculator include employer NI?
No. Employers pay separate Class 1 secondary contributions on employee wages. This tool estimates employee Class 1 or self-employed Class 2 and Class 4 amounts only.
Which tax year does this calculator use?
Default thresholds and rates follow tax year 2025/26. You can switch to 2024/25 in the calculator when comparing prior-year figures.

Resources and references

The formulas and methods in this calculator were checked against these independent sources.