Useful next calculations
Rates and 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.
Example: checking whether a retirement plan is on pace
Use these sample inputs as a quick scenario test, then change one variable at a time to compare outcomes.
| Input | Value |
|---|---|
| Current retirement balance | £45,000 |
| Monthly contribution | £400 |
| Expected annual growth | 6% |
| Years to retirement | 25 years |
The value here is seeing whether the current contribution pace is doing enough work on its own, or whether the plan leans too heavily on optimistic growth assumptions.
Method & assumptions
Projects a nominal pot using monthly contributions at the end of each month and monthly compounding at the annual rate divided by 12. Explicit zero contributions or growth are supported. Retirement age must be at least current age.
The monthly allocation divides that pot equally over the years from retirement to the payout end age you choose. The end age is your planning assumption, not a prediction of life expectancy. It must be later than retirement age. No returns during drawdown, inflation, taxes, fees, State Pension, contribution tax relief or investment risk are modelled. This is not an annuity quote or a guaranteed sustainable income.
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.