How Long Will Your Pension Last?

Why "will my pension last?" is the wrong question

Most people approaching retirement ask a simple question: how long will my money last? But the real answer depends on how your different income sources work together. Your State Pension, workplace pensions, SIPPs, ISAs, and savings each have different tax treatments, access ages, and growth rates. A pension pot of £300,000 lasts very differently depending on whether you're drawing it down at 55 or 66, and whether you have ISA savings to bridge the gap before your State Pension starts.

That's exactly what this calculator models. Rather than giving you a single number, it shows you year by year how your money flows — which accounts you draw from, when your State Pension kicks in, how tax affects your withdrawals, and crucially, whether you run out.

How pension drawdown actually works

When you reach pension age (currently 55, rising to 57 in 2028), you don't have to buy an annuity. Most people now choose flexi-access drawdown — your pension stays invested and you withdraw what you need. You can take 25% as a tax-free lump sum, and the rest is taxed as income.

The challenge is working out how much you can safely withdraw each year without running out too early. Take too much and you risk poverty in your 80s. Take too little and you've denied yourself the retirement you earned. Our calculator helps you find the balance by modelling your actual numbers — not averages or rules of thumb.

What makes this calculator different

Most retirement calculators ask for one pension pot and one spending number, then divide one by the other. That's not how retirement works in the UK. You might have a defined benefit pension paying £8,000 a year from 65, a SIPP with £200,000 you can access from 57, ISA savings of £50,000, and a State Pension of £11,500 from 67.

This calculator handles all of that. You enter each income source separately, with its own start date and growth assumptions. It models the tax on pension withdrawals, accounts for inflation on your spending, and shows you a year-by-year breakdown of exactly where your money comes from and when it runs out — if it runs out at all. Everything runs in your browser. Nothing is stored, nothing is sent to a server, and there's nothing to sign up for.

Is this calculator really free?

Yes, completely free with no registration required. We built it for a family member and decided to make it available to everyone. There are no premium tiers, no upsells, and no data collection.

How accurate are the results?

The calculator uses current UK tax bands, National Insurance thresholds, and State Pension rates for the 2025/26 tax year. Investment growth and inflation are projections based on the rates you choose — we suggest sensible defaults but you can adjust them. No calculator can predict the future, but this gives you a realistic model to plan around.

Is my data safe?

Your data never leaves your browser. All calculations run locally using JavaScript — nothing is sent to any server. When you close the tab, your data is gone. You can verify this yourself: the site works fully offline once loaded.

Can I model early retirement?

Yes. Enter your target retirement age and the calculator will show the gap between when you stop working and when each pension becomes available. This is particularly useful if you're considering retiring at 55 or 60, well before your State Pension age of 66 or 67.