Investment Calculators
Investment Calculator
Enter a starting balance, what you add each month and a realistic long-run return to see how the balance is expected to develop.
Projected value
$341,238
- Total invested
- $140,000
- Investment growth
- $201,238
- Growth multiple
- 2.44×
How this calculator works
FV = P(1 + r)^n + C × [((1 + r)^n − 1) ÷ r]
- P
- the starting amount
- C
- the regular contribution
- r
- the periodic return
- n
- the number of periods
Example calculation
Illustrative example — not advice
Worked example — the investment calculator as it loads, using the default figures below.
- 01Enter starting amount: $20,000.
- 02Enter monthly contribution: $500.
- 03Enter expected annual return: 7%.
- 04Enter years invested: 20 years.
- 05Read the projected value from the results panel: $341,238.
Projected value: $341,238. Total invested: $140,000. Investment growth: $201,238. Growth multiple: 2.44×.
These figures come straight from the calculator above running on the values listed, so you can retype them and confirm every number yourself. Change any input and the results update immediately. Illustrative only — not a quote, offer or recommendation.
Important considerations
- Returns are assumed to be smooth; real markets are not.
- Fees, taxes and inflation all reduce the outcome.
Related calculators
- Compound Interest CalculatorProject the growth of a balance with compounding and regular contributions.
- Future Value CalculatorWhat a sum today is worth in the future.
- Investment Fee CalculatorWhat annual charges cost you over the long run.
- CAGR CalculatorCompound annual growth rate between two values.
- Retirement CalculatorProject your retirement balance and the income it could sustain.
- ROI CalculatorTotal and annualised return on any investment.
Terms used here
Frequently asked questions
What return should I assume?
Use a conservative long-run figure and test a lower one. Small changes to the assumption compound into large differences.
Disclaimer
Legamoney calculators are educational tools. Results are estimates based on the figures you enter and do not constitute financial, tax or legal advice.
Last reviewed 2026-08-01