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UK · 2025/26

SIPP Calculator

Calculate SIPP pension pot growth with tax relief. Project your retirement fund from annual contributions.

Last reviewed: 22 November 2025Source: HMRC — Pension schemesUpdated every: tax year
SIPP Calculator · UKInvestments & Savings

Gross Contribution

£10,000.00/yr

Projected Pot

£438,651.77

Your Cost

£160,000.00

Rates & sources2025/26

Pension annual allowance, tapered for high earners. LTA abolished from 2024.

Annual allowance£60,000
Tapered for income over£260,000
Minimum tapered allowance£10,000
Carry-forward3 prior tax years

Source: HMRC — Pension schemes — 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.

Your Annual Contribution (£)

£250 per month

Your Tax Rate (%)

5%

Years Until Retirement

10 years

Annual Return (%)

7

After entering these figures, review gross contribution, projected pot and your cost 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

Gross Contribution

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 Pot

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.

Your Cost

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 projects the growth of a SIPP over time and may also estimate a potential retirement income. Contributions entered should be net of basic rate tax relief — for example, enter £800 if you actually pay in £800, and the calculator assumes the government adds the 20% top-up to reach £1,000 gross. Higher rate and additional rate taxpayers should also claim their extra relief via self-assessment.

The calculator assumes a fixed annual investment return net of fund and platform charges and does not model annual allowance tapering for very high earners or the money purchase annual allowance triggered by flexi-access drawdown. The 25% tax-free lump sum entitlement is shown illustratively and is subject to the current lump sum and death benefit allowance. This tool is for planning purposes only and does not constitute financial advice — consider consulting a regulated financial adviser before making SIPP decisions.

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.

Go deeper — 4 guides reference this calculator

Frequently asked

HMRC adds basic rate (20%) tax relief to your contributions automatically. A £800 net contribution becomes £1,000 in your SIPP. Higher rate taxpayers claim the additional 20% through self-assessment.

Use arrow keys to navigate items, Enter or Space to expand/collapse.

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