Investment Calculator
Solve for end balance, required return, starting amount or contribution on any investment.
About Investment Calculator
Your future value is the growth of your initial investment plus the future value of each annual contribution, compounded at your expected annual return. Total return compares your ending balance to everything you put in.
Formulas
Future value of lump sum
FV_P = P × (1 + r)ᵗ
- FV_P
- Future value of initial investment
- P
- Initial investment (principal)
- r
- Annual return rate (decimal)
- t
- Years invested
Future value of annual contributions
FV_C = PMT × ((1 + r)ᵗ − 1) / r
- FV_C
- Future value of all contributions
- PMT
- Annual contribution
Total return
Total Return % = (FV − Total Invested) / Total Invested × 100
- FV
- Total future value (FV_P + FV_C)
Worked example
With the default values below, Investment Calculator returns Future Value of $541,363. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Initial Investmentaccepts 0–10,000,000 $
- 15,000 $
- Annual Contributionaccepts 0–1,000,000 $
- 6,000 $
- Expected Annual Returnaccepts 0–30 %
- 8 %
- Yearsaccepts 1–60 years
- 25 years
Results
- Future Value
- $541,363
- Total Invested
- $165,000
- Total Gain
- $376,363
- Total Return
- 228.1%
Step by step
- 1Growth factor over the investment period: (1 + r)ᵗ= 6.8485
- 2Future value of the initial lump sum: P × (1 + r)ᵗ= $102,727
- 3Future value of annual contributions: PMT × ((1 + r)ᵗ − 1) / r= $438,636
- 4Total future value= $541,363
- 5Total amount invested= $165,000
- 6Total return on investment= $376,363 (228.1%)
Assumptions and limits
- The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax or fees or charges into account.
- Figures are rounded for display to 1 decimal place, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
- Projections are estimates only and not investment advice. Investments can lose value.
- This is an estimate for general information and not professional financial, tax or legal advice. See the full disclaimer for the limits that apply to this kind of calculator.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Investment Calculator — full guide
Two engines, one balance
An investment account grows from two distinct sources: the lump sum you start with, which compounds for the entire period, and the contributions you add each year, which each compound for progressively less time. The calculator works them out separately, adds them, and then states the gain as a percentage of every rupee or dollar you put in.
It answers practical questions: is a windfall better used to seed the account or to raise the annual contribution, and how much is one percentage point of return actually worth.
The three formulas
FV_P = P × (1 + r)^t — growth of the initial investment
FV_C = PMT × [((1 + r)^t − 1) ÷ r] — growth of the annual contributions
Total Return % = (FV − Total Invested) ÷ Total Invested × 100
P is the initial investment, PMT the annual contribution, r the expected annual return as a decimal and t the number of years. Contributions are treated as arriving at the end of each year, so the first one compounds for t − 1 years rather than t.
The defaults, worked
$15,000 initial, $6,000 a year, 8% expected return, 25 years. First, 1.08^25 = 6.848475.
- Initial sum grows to 15,000 × 6.848475 = $102,727
- Annuity factor: (6.848475 − 1) ÷ 0.08 = 73.1059
- Contributions grow to 6,000 × 73.1059 = $438,636
- Future value: 102,727 + 438,636 = $541,363
- Total invested: 15,000 + (6,000 × 25) = $165,000
- Total gain: 541,363 − 165,000 = $376,363
- Total return: 376,363 ÷ 165,000 × 100 = 228.1%
| Component | Amount |
|---|---|
| Growth of the initial $15,000 | $102,727 |
| Growth of 25 annual contributions | $438,636 |
| Future value | $541,363 |
| Total invested | $165,000 |
| Total gain | $376,363 |
Reading the return figure
228.1% is cumulative across twenty-five years, not annual, and dividing it by 25 produces a meaningless number. What it says plainly is that the ending balance is 3.28 times the money contributed, produced by the 8% you entered.
The return input dominates every other field. Lower it from 8% to 7% and the future value drops to $460,906 — $80,457 less from a single percentage point. That gap is the argument behind every discussion of fund fees.
Assumptions to keep in view
- A constant annual return. Markets deliver a sequence instead, and the order of good and bad years matters once you start withdrawing.
- No fees and no tax on dividends or realised gains.
- Contributions never rise. If yours track your salary, raise the figure and re-run rather than assuming the result holds.
- The answer is in future money. At 3% inflation, $541,363 twenty-five years out has roughly the buying power of $258,558 today.
Projections only, not investment advice. For monthly rather than annual contributions use the compound interest calculator, translate the result into today's money with the inflation calculator, and test it against a target income in the retirement calculator.
Guides that use this calculator
Projections are estimates only and not investment advice. Investments can lose value.
Frequently Asked Questions
What return rate should I use?
Historically, a diversified stock portfolio has averaged roughly 7–10% annually before inflation, but past performance never guarantees future results.
Does this account for taxes or fees?
No. Real returns are reduced by investment fees and taxes on gains, which vary by account type and jurisdiction.
I have $10,000 spare. Is it better added to the initial amount or spread across future contributions?
Put it in now. Adding it to the initial investment takes the default result from $541,363 to $609,848. Spreading the same $10,000 as $400 extra a year for 25 years reaches only $570,605. The lump sum gets the full twenty-five years of compounding, while each annual slice gets less — a difference of $39,242.
The calculator adds contributions at year end. What would start-of-year contributions give?
About 8% more on the contribution half. Multiplying the $438,636 contribution growth by 1.08 lifts the future value from $541,363 to $576,454, a gain of $35,091 purely from timing. If you genuinely invest in January each year, treat the displayed result as slightly conservative rather than adjusting the inputs.
Why is the total return 228% rather than 8% × 25 = 200%?
Because the two figures measure different things. The 8% compounds each year rather than adding linearly, which pushes returns up; but each annual contribution is invested for less than the full term, which pulls the percentage down. The 228.1% is the net of those two effects against the $165,000 actually contributed.
Should I enter a nominal return or subtract inflation first?
Either works if you stay consistent. Enter 8% and the $541,363 is in future dollars. Enter a real rate instead — roughly 4.85% for 8% nominal less 3% inflation — and the result, about $329,523, is already in today's purchasing power. Mixing a nominal rate with today's prices is the mistake to avoid.