Retirement planning comes down to three numbers: what you will have, what you will need and how long it has to last. A good retirement planning calculator makes you estimate each one honestly rather than hiding the assumptions behind a single answer.
Start with the State Pension
For 2026/27 the full new State Pension is £241.30 a week, about £12,548 a year. You need 35 qualifying National Insurance years for the full amount and at least 10 to get anything. State Pension age is rising from 66 to 67 between 2026 and 2028, so check your own date rather than assume. You can check your State Pension forecast on GOV.UK before you use any tool, because it is the one input that is both personal and official.
What a retirement planning tool should ask for
- Your pensions. Workplace pensions, personal pensions and older pots you may have lost track of
- Your spending. Essential costs and nice-to-haves, because they are not equally flexible
- Retirement age and life expectancy. Plan to 90 or beyond rather than to the average
- Inflation and investment growth. The tool should show cautious assumptions as well as optimistic ones
- Tax. Income tax on pension income, and the tax-free cash you can usually take, normally up to 25% subject to a limit
Free retirement planning calculators and tools
A retirement planning calculator from MoneyHelper, the government-backed service, is free and isn't trying to sell you anything. Retirement planning tools from pension providers can be useful for your own pot but may only show their own products. Spreadsheet planners let you test scenarios in more detail. Whichever retirement planning tool you use, run it three times: a cautious case, a middle case, and a case where you retire earlier or later than planned.
One contribution limit to know
The standard pension annual allowance is £60,000, or 100% of your earnings if lower, for tax-relieved contributions. Most people never come close, but higher earners and people with large employer contributions should check.
When a calculator isn't enough
If you have a defined benefit pension, are thinking of transferring, or are close to retirement with several pots, speak to an FCA-authorised advisor. See our guide on how to find a financial advisor in the UK. Pension Wise offers free guidance to people aged 50 or over with defined contribution pensions. For tools that model your wider finances, see financial planning software in the UK.