National Insurance Contributions Calculator
This National Insurance calculator covers employee Class 1 NI deducted via PAYE and self-employed Class 4 NI on profits. It uses 2026-27 thresholds and rates from GOV.UK.
Educational estimate. Calculator results are for planning and information only, not financial, tax, medical, legal, or engineering advice. Verify important decisions with official sources or a qualified professional.
National Insurance Contributions Calculator
Class 1 & 4 NI - Employee & Self-Employed
📐 Formula & Method
Class 1 (Employees) 2026-27
Most employees pay Class 1 NI at 8% in the main band and 2% above the upper earnings limit.
Class 4 (Self-Employed) 2026-27
Self-employed workers pay Class 4 NI on profits above the Lower Profits Limit. Class 2 is voluntary at £3.65/week in 2026-27.
📋 How to Use
-
1
Enter your annual earnings or self-employed profit.
-
2
Select employed or self-employed.
-
3
See your annual NI contribution broken down by band.
National Insurance - 2026-27 Rates Explained
National Insurance funds the NHS, State Pension, and other benefits. Employees pay Class 1 NI; employers pay a separate employer NI contribution (not shown here). Self-employed people pay Class 4 NI on profits and can voluntarily pay Class 2 to protect their State Pension entitlement.
For 2026-27, most employees pay 8% Class 1 NI between the primary threshold and upper earnings limit, then 2% above that. Self-employed Class 4 uses a 6% main rate and 2% additional rate.
🔬 Methodology & Accuracy
Formula: Employee NI applies 8% between £12,570 and £50,270 and 2% above £50,270. Self-employed Class 4 applies 6% between £12,570 and £50,270 and 2% above £50,270. Voluntary Class 2 is described but not auto-added.
Data sources: GOV.UK National Insurance rates: https://www.gov.uk/national-insurance/how-much-you-pay; GOV.UK rates and allowances for National Insurance contributions: https://www.gov.uk/government/publications/rates-and-allowances-national-insurance-contributions/rates-and-allowances-national-insurance-contributions; GOV.UK voluntary National Insurance rates: https://www.gov.uk/voluntary-national-insurance-contributions/rates
Last reviewed: June 2026 · General formula used: Class 1 (Employees) 2026-27 · Accuracy: Results are precise to two decimal places using IEEE-754 double-precision arithmetic. Intended for educational and planning use only.
For informational purposes only. Results are estimates based on the inputs and formulas provided. For financial, tax, medical, or legal decisions, consult a qualified professional. Rates and regulations change — always verify current figures with official sources.