How to calculate pension tax relief

Tax relief means a pension contribution costs you less than it adds to your pot. The government tops up your contribution at your marginal rate, so a higher-rate taxpayer can add a pound to their pension for a fraction of that from take-home pay.

The rule

Net cost = gross contribution × (1 − your marginal tax rate)

Do it automatically — Pension tax relief

Step by step

  1. 1Decide the gross amount you want to land in the pension.
  2. 2Find your marginal rate — the rate on the top slice of your income.
  3. 3Multiply the gross contribution by one minus that rate to get the real cost to your take-home pay.
  4. 4Check whether the contribution pulls your income below a threshold, which can increase the effective relief sharply.

What trips people up

  • Higher-rate relief often has to be claimed through a tax return under relief-at-source schemes.
  • Annual and lifetime allowance limits cap how much can be contributed tax-efficiently.

Common questions

Salary sacrifice or personal contribution?

Salary sacrifice also saves social contributions, so it is usually the more efficient route.

Can I carry forward unused allowance?

In many cases yes, for a limited number of previous years if you were a scheme member.

Skip the maths

See the tax relief added by the government and the net cost from your take-home.

Open the the real cost of a contribution tool

More how-to guides