Investment Calculators for Retirement Planning
Plan your retirement with compound interest, pension, and retirement savings calculators.
CalculatorZone Editorial Team12 min readPublished Updated
Retirement Planning Calculators: The UK Complete Guide
Retirement planning is a numbers game — and the sooner you start running the numbers, the more comfortable your retirement will be. Whether you want to retire at 55, 65, or aim for Financial Independence (FIRE), the right calculators will show you exactly what pot size you need, what monthly savings get you there, and how State Pension fits in.
The New State Pension (2026/27)
The full new State Pension for 2026/27 is £241.30 per week(£12,547.60 per year), following the triple lock increase. You need 35 qualifying National Insurance years to receive the full amount, and a minimum of 10 years for any State Pension at all. State Pension age is currently 66 for both men and women, rising to 67 between 2026 and 2028.
How Much Pension Pot Do You Need?
| Target Annual Income | Less State Pension | From Pension Pot | Pot Needed (4% rule) |
|---|---|---|---|
| £20,000 | £12,548 | £7,452 | £186,300 |
| £30,000 | £12,548 | £17,452 | £436,300 |
| £40,000 | £12,548 | £27,452 | £686,300 |
| £50,000 | £12,548 | £37,452 | £936,300 |
The 4% Safe Withdrawal Rule
The 4% rule (from the Trinity Study) states that withdrawing 4% of your portfolio in year one, then adjusting for inflation each year, sustained a portfolio for 30+ years in the historical US data it was based on. There is no guarantee that it will do so in future. In UK terms with higher inflation and lower historic equity returns than the US, many planners use 3.5% to be conservative. Your FIRE number is therefore your target annual income divided by 0.04 (or 0.035 for the conservative version).
Example: target income of £25,000/year ÷ 0.04 = FIRE number of £625,000. If State Pension contributes £12,548, your private pot only needs to generate £12,452/year, requiring £311,300.