Investments in pensions grow free from income tax and capital gains tax. Pension contributions are paid from gross (pre-tax) income. Where tax has already been paid on a pension contribution it is refunded. The tax office will automatically top up pension contributions up to your annual allowance by 20% to cover basic rate tax. Higher or additional-rate tax payers can then claim back any higher or additional-rate tax that they have paid on contributions through their tax return.