Is National Insurance a tax?

Legally it is a social security contribution, not income tax, and it is governed by different rules. Economically it functions like a tax on earnings.

Do I pay NI on pension contributions?

Salary sacrifice reduces NI. Net-pay and relief-at-source pension contributions do not reduce employee NI.

Can I claim a refund of overpaid NI?

Yes, if you have multiple jobs or your employer used the wrong category. Contact HMRC or claim through a self assessment return.

EarnAfterTax

Understanding National Insurance

National Insurance is not a tax on your income tax bill — it has its own thresholds, its own rate structure, and a genuine planning opportunity through salary sacrifice.

Continue

GOV.UK — National Insurance rates and categories
GOV.UK — Rates and thresholds for employers 2026 to 2027
GOV.UK — Salary sacrifice

This page needs JavaScript for the interactive calculator. All rates, assumptions and sources are published in the methodology.