Continue your plan
Useful next calculations
Rates & sources
Compound growth assumes reinvested returns and no platform fees. Past performance is not a guide to future returns.
Source: FCA — Investment basics — check the linked guidance and any live quote before acting.
When to use this calculator
- Before choosing between saving, investing or changing a contribution.
- When you want to compare cautious, base and optimistic return assumptions.
- When you need a projection before making a longer-term decision.
- When you want to see whether starting earlier or contributing more changes the outcome more.
A realistic UK planning example
Use these sample inputs as a quick scenario test, then change one variable at a time to compare outcomes.
| Input | Value |
|---|---|
| Present Value (£) | 10000 |
| Annual Interest Rate (%) | 5% |
| Years | 10 years |
| Compounds Per Year | 10 years |
After entering these figures, focus on result first and then rerun the tool with a more cautious assumption.
How to read your results
Result
The figure produced by this output for the inputs you entered. Change one variable at a time if you want to see what drives it.
Method & assumptionsAuthoritative sources
This calculator uses the standard future value formula, applying compound interest to either a one-off lump sum, regular contributions, or a combination of both. You can adjust the compounding frequency to match your investment product — annual compounding suits most stocks and shares investments and ISAs, while monthly suits savings accounts that compound interest monthly.
The calculator assumes a fixed rate of return throughout the period, which is a simplification. In practice, investment returns vary each year. For long-term equity investments, many UK planners use a 5–7% nominal annual growth assumption before charges. Always deduct your platform and fund charges from the return rate to model a net figure. This tool does not account for tax, inflation, or changes in contribution levels over time.
Common mistakes
- !Assuming a constant return without checking a more conservative growth rate.
- !Forgetting 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 charges over a long period.
What to do next
- Test a cautious, expected and optimistic growth rate.
- Compare this result with related savings or retirement tools before committing more money.
- Consider charges and any tax wrapper that applies.
- If the projected balance falls short, increase the contribution until the result meets your goal.
Frequently asked
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