Free ROI Calculator — Calculate Return on Investment
Work out what an investment, a campaign, or a purchase actually returned. Enter what it cost and what it is worth now: you get the return on investment as a percentage, the profit in cash, and — if you add a time period — the annualised return that makes a two-year result comparable with a five-year one. Add several investments to the comparison table to rank them side by side. Everything is calculated in your browser.
The base formula is plain arithmetic: ROI = (final value − cost) ÷ cost × 100. Turn $10,000 into $13,500 and the ROI is 35%. The number is popular because it works on anything with a cost and a result — a rental flat, a stock position, a trade show, a new machine, a hire — but that generality is also its weakness, which is why the sections below spell out what it hides.
Annualised ROI is the figure that actually compares
A raw ROI says nothing about speed. A 35% return is excellent in one year and mediocre over ten. Annualised ROI fixes that by spreading the gain across the holding period: [(1 + ROI ÷ 100)1/years − 1] × 100. That same $10,000 → $13,500 over 24 months is 35% in total but 16.2% a year, which is the figure you can put next to a savings rate or an index fund. Enter the duration in months and the calculator shows both.
Marketing ROI and ROAS are different numbers
ROAS is revenue divided by ad spend; ROI subtracts the cost before dividing. Spend $2,000 and bring in $8,000 and the ROAS is 4:1, which sounds like a win — but if the gross margin on that revenue is 25%, the campaign generated $2,000 of margin against $2,000 of spend and the ROI is 0%. For a marketing campaign, put the gross profit the campaign produced in the gain field rather than the revenue, otherwise the result flatters the campaign.
What ROI leaves out
ROI ignores risk entirely: a 30% return on a speculative position and a 30% return on a bond look identical here. It ignores when cash moves, so a project that pays out early scores the same as one that pays at the end. It ignores tax, fees, and inflation unless you subtract them yourself, and it ignores what else you could have done with the money. For uneven cash flows in and out over time, an IRR or NPV calculation is the correct tool; ROI is a summary, not a decision.
Related maths lives in the compound interest calculator for growth over time, the profit margin calculator for the margin you should be feeding into marketing ROI, and the savings goal calculator for working backwards from a target.
How to use ROI Calculator
- Enter what the investment cost you in the initial investment field — the full amount you put in, including fees if you know them.
- Enter either the final value or the gain, whichever you actually have. The calculator switches between the two input modes and derives the other one.
- Add the duration in months if the investment ran for a known period. That unlocks the annualised return, which is the number worth comparing.
- Read the three results: ROI as a percentage, the profit in cash, and the annualised figure. A negative ROI means the position is down by that percentage.
- Add rows to the comparison table to rank several investments at once, then copy the summary for a report or a decision memo.
Features
- Two input modes — work from the final value or straight from the gain, whichever number you have to hand.
- Annualised ROI — spreads the total return across the holding period so a two-year and a five-year result can be compared honestly.
- Side-by-side comparison — add several investments with their own amounts and durations and see them ranked.
- Formulas shown on the page — both the simple and the annualised formula are printed so you can reproduce any result by hand.
- Benchmark context — long-run averages for equities, property, Treasuries, savings and marketing, dated and labelled as rules of thumb rather than forecasts.
- Runs in your browser — amounts and returns are never sent to a server, and there is no account or sign-up.
Frequently Asked Questions
How do I calculate ROI?
Subtract the cost from the final value, divide by the cost, and multiply by 100. A $10,000 investment worth $13,500 gives (13,500 − 10,000) ÷ 10,000 × 100 = 35%. If you only know the profit, divide the profit by the cost and multiply by 100 — the calculator accepts either input.
What is a good ROI?
It depends entirely on the risk and the time. As context: the S&P 500 has returned roughly 10% a year before inflation over the long run, the best high-yield savings accounts paid about 4% in September 2026, and marketing teams commonly treat a 5:1 revenue-to-cost ratio as a healthy campaign. A 20% ROI earned over ten years is worse than a 6% return earned in one, which is why the annualised figure matters more than the headline.
What is the difference between ROI and ROAS?
ROAS divides revenue by ad spend and ignores the cost of what you sold. ROI subtracts all the costs first. A 4:1 ROAS on a product with a 25% gross margin is a break-even campaign, not a good one. For marketing ROI, use the gross profit generated rather than the revenue.
How do I calculate annualised ROI?
Take [(1 + ROI ÷ 100)^(1 ÷ years) − 1] × 100. A 35% total return over two years is 16.2% a year; the same 35% over five years is 6.2% a year. Enter the duration in months and this is calculated for you.
Does this ROI calculation include tax, fees, or inflation?
Only if you include them in the numbers you enter. ROI is arithmetic on the figures it is given. To get a real return, subtract inflation from the annualised result; to get an after-tax return, use the after-tax proceeds as the final value.
Can ROI be negative?
Yes. If the final value is below the cost, the ROI is negative and shows how much of the original amount was lost. A −40% ROI means the position is worth 60% of what you paid, and recovering from it requires a 66.7% gain, not a 40% one.
Why does ROI not tell me which investment is better?
Because it says nothing about risk, timing, or what happens to the money afterwards. Two investments with identical ROI can have completely different chances of losing everything. Use ROI to measure what happened, and judgement — or an IRR and NPV calculation for uneven cash flows — to decide what to do next.
Are my figures saved or sent anywhere?
No. The calculation runs in your browser, nothing is transmitted, and there is no account. Closing the tab discards the numbers.