Rates & sources
Compound growth assumes reinvested returns and no platform fees. Past performance is not a guide to future returns.
Source: FCA — Investment basics — figures refreshed at the start of each tax year.
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When to use this calculator
- Before choosing between saving, investing, or increasing your monthly contribution.
- When you want to compare best-case, base-case, and cautious return assumptions.
- When you need a quick projection before making a longer-term portfolio decision.
- When you are deciding how many more years of contributions are needed to reach a specific target balance.
- When you want to see whether starting earlier versus contributing more each month produces a bigger outcome.
A realistic UK planning example
Use these sample inputs as a quick scenario test, then change one variable at a time to compare outcomes.
Qualifying National Insurance Years
10 years
Your Current Age
35
Planned Retirement Age
66 (State Pension age)
After entering these figures, review current weekly pension, current annual and projected weekly at retirement together rather than in isolation — each metric tells a different part of the story. Then rerun the tool with one input adjusted to see which variable has the biggest effect on all three outputs before you settle on a plan.
How to read your results
Current Weekly Pension
Use this metric to compare scenarios side by side and understand how changes in the key inputs drive the final outcome. If the figure surprises you, isolate one variable at a time and rerun the calculation to identify which assumption is responsible.
Current Annual
Use this metric to compare scenarios side by side and understand how changes in the key inputs drive the final outcome. If the figure surprises you, isolate one variable at a time and rerun the calculation to identify which assumption is responsible.
Projected Weekly at Retirement
Use this metric to compare scenarios side by side and understand how changes in the key inputs drive the final outcome. If the figure surprises you, isolate one variable at a time and rerun the calculation to identify which assumption is responsible.
Projected Annual
Use this metric to compare scenarios side by side and understand how changes in the key inputs drive the final outcome. If the figure surprises you, isolate one variable at a time and rerun the calculation to identify which assumption is responsible.
NI Years Still Needed
Use this metric to compare scenarios side by side and understand how changes in the key inputs drive the final outcome. If the figure surprises you, isolate one variable at a time and rerun the calculation to identify which assumption is responsible.
Method & assumptionsAuthoritative sources
This calculator uses the new State Pension rules that apply to anyone reaching State Pension age on or after 6 April 2016. The full weekly rate of £221.20 for 2024/25 is used as the baseline, and your entitlement is calculated proportionally based on the number of qualifying National Insurance years you have entered, up to the 35-year maximum. The 10-year minimum threshold is enforced — entering fewer than 10 years returns zero entitlement. The projection to retirement adds the number of remaining working years to your current NI record, assuming one qualifying year is accrued per year worked, and calculates the likely weekly and annual pension you would receive if you continue contributing at the same rate.
The calculator does not model the triple lock or future uprating, voluntary NI contributions, contracting-out deductions that may apply to pre-2016 records, or deferral bonuses for claiming after State Pension age. It is intended as an indicative planning tool only. For a personalised State Pension forecast that reflects your actual NI record, use the Check Your State Pension service at gov.uk. Rates and thresholds are based on the 2024/25 tax year and are subject to change at each Autumn Budget.
Common mistakes
- !Assuming a constant return without checking a more conservative growth rate.
- !Forgetting to include ongoing contributions, fees, or tax wrappers where relevant.
- !Focusing only on the final balance instead of the path required to reach it.
- !Ignoring the drag of platform fees or fund charges, which can reduce the real compounded return significantly over ten or more years.
- !Comparing ISA and general investment account projections without adjusting for the tax treatment of interest, dividends, or capital gains.
What to do next
- Test a cautious, expected, and optimistic growth rate instead of relying on a single projection.
- Compare this result with related savings or retirement tools before committing more money.
- Use the linked guides to understand which assumptions matter most over longer periods.
- Consider running the same figures in an ISA and a general account scenario to see how the tax treatment changes the outcome over ten or more years.
- If the projected balance falls short of your target, use the tool to work backwards — increase the monthly contribution until the result meets your goal.
Frequently asked
Use arrow keys to navigate items, Enter or Space to expand/collapse.
End-of-article next steps
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