Formula used
- Lump sum: FV = PV × (1 + r)n.
- Regular payments: FV = PMT × (((1 + r)n − 1) ÷ r).
- Beginning payments multiply the annuity result by (1 + r).
- Real value divides nominal value by accumulated inflation.
- Fees, taxes, deposits, and withdrawals apply during each period.
How to use this calculator
- Select the calculation mode matching your investment question.
- Enter your starting amount, contributions, return, and duration.
- Add fees, taxes, inflation, dividends, or withdrawals when relevant.
- Choose yearly or monthly detail, then calculate the projection.
- Review scenarios, charts, goal progress, and downloadable reports.
Example investment data
| Plan | Initial amount | Monthly contribution | Return | Years | Fee |
|---|---|---|---|---|---|
| Conservative | £10,000 | £250 | 4.00% | 15 | 0.50% |
| Balanced | £10,000 | £300 | 7.00% | 20 | 0.75% |
| Growth | £15,000 | £500 | 9.00% | 25 | 0.90% |
Investment planning guidance
Compound growth becomes stronger across longer investment periods. Regular deposits can reduce reliance on perfect market timing. Consistent investing often supports steadier progress toward long-term goals.
Fees quietly reduce returns throughout every investment period. Inflation also lowers the future purchasing power of money. Compare nominal and real outcomes before making important decisions.
Higher expected returns usually involve greater possible losses. Scenario testing helps reveal uncertainty around future investment outcomes. Use cautious assumptions and review your plan regularly afterward.
Frequently asked questions
What does this investment calculator estimate?
It estimates growth, contributions, fees, taxes, and withdrawals. Results include nominal and inflation-adjusted balances for comparison. These projections support planning but never guarantee investment performance.
Can I calculate a required monthly contribution?
Yes, select the required regular contribution calculation mode. Enter your target, duration, return, and existing investment. The calculator estimates contributions needed under those selected assumptions.
How are beginning contributions treated?
Beginning contributions enter before each period earns investment growth. End contributions enter after growth for that same period. Beginning payments therefore receive slightly more compounding time overall.
Why include inflation in the projection?
Inflation reduces what future money can actually purchase. Real balances express projected wealth using today’s purchasing power. This comparison creates more practical long-term planning expectations overall.
How do management fees affect results?
Management fees reduce the balance available for future growth. Small annual percentages can become substantial over long periods. Compare fee levels before choosing an investment product carefully.
Can the calculator use variable annual returns?
Yes, enter yearly percentages separated using commas or spaces. Each entered value replaces the standard return that year. Remaining years continue using the expected annual return assumption.
What does the randomised simulation show?
It creates many paths using return and volatility assumptions. Lower, median, and higher balances summarise simulated ending outcomes. The success rate shows paths reaching your chosen target.
Are taxes calculated exactly?
No, tax rules vary across accounts and jurisdictions. This model applies a simplified annual gain tax method. Confirm actual tax treatment with a qualified adviser locally.
Can I model retirement withdrawals?
Yes, enter an annual withdrawal and starting year. Optional increases can reflect rising future income requirements. The balance cannot fall below zero during projections shown.
What return should I enter?
Use a cautious return matching your investment risk. Compare conservative, expected, and optimistic scenarios before deciding. Historical performance never guarantees the same future returns occurring.
Does dividend reinvestment change the result?
Reinvested dividends stay invested and earn future compounded growth. Cash dividends are recorded separately from the ending balance. Reinvestment can increase long-term balances when returns remain positive.
Financial disclaimer
This calculator provides educational estimates, not personal financial advice. Markets, taxes, inflation, fees, and returns may change. Consider qualified guidance before making major investment decisions yourself.