Formula Used
A is the ending balance. P is the starting principal. Rates and periods determine total investment growth over time.
How to Use
Select the required calculation mode. Enter principal, rate, duration, and contributions. Then review every result before making financial decisions.
Choose compounding and contribution frequencies. Add inflation, tax, and fee assumptions. Advanced settings model changing rates and dated cash flows.
Press Calculate to generate results. Switch schedule views for deeper analysis. Download or print reports for convenient future reference.
Example Data
| Example | Principal | Rate | Duration | Contribution | Frequency |
|---|---|---|---|---|---|
| Long-term savings | £10,000 | 5% | 10 years | £100 monthly | Monthly |
| Education fund | £5,000 | 4.5% | 15 years | £150 monthly | Quarterly |
| Retirement plan | £25,000 | 6% | 25 years | £300 monthly | Monthly |
| Deposit target | £2,500 | 3.8% | 5 years | £200 monthly | Daily |
Common Mistakes
Nominal rates differ from effective rates. Contribution timing also changes final balances. Always match the calculator assumptions with your account.
Inflation reduces future purchasing power. Fees and taxes reduce realised returns. Include both for more realistic long-term projections.
Variable returns are never guaranteed. Projections show mathematical scenarios only. Compare several rates before choosing your investment strategy.
Frequently Asked Questions
What is compound interest?
Compound interest earns returns on previous interest. Growth accelerates across longer investment periods. More frequent compounding can slightly increase final balances.
How does contribution timing affect results?
Beginning contributions receive more growth time. Ending contributions receive slightly less interest. The difference becomes larger across long durations.
What is an effective annual rate?
The effective rate includes compounding effects. It exceeds the nominal rate when compounding repeats. Use it for clearer account comparisons.
Does daily compounding use leap years?
The actual-days option recognises leap years. It uses 365 or 366 days. This improves daily projections across calendar years.
Can the calculator include taxes?
Yes, taxes can reduce positive interest. Negative interest receives no tax deduction. Enter your estimated tax percentage carefully.
How are fees calculated?
Fixed fees apply once yearly. Percentage fees use the current balance. Both deductions appear within detailed schedule rows.
Can interest rates change yearly?
Yes, enter yearly rates separately. Each listed year overrides the standard rate. Unlisted years continue using the standard rate.
What does inflation-adjusted value mean?
It estimates future purchasing power today. Higher inflation lowers the adjusted amount. This comparison supports realistic long-term planning.
Are these results guaranteed?
No calculator can guarantee investment returns. Rates, fees, and taxes may change. Use projections as planning estimates, not promises.