ROI vs Annualised Return: Comparing Investments Fairly

ROI's superpower and its blind spot

Return on investment — profit divided by cost, as a percentage — is the most portable performance number in finance because it strips out scale. A 200 gain on 1,000 and a 2,000 gain on 10,000 are both 20% ROI, which makes a savings account, a stock position, a marketing campaign and a rental flat comparable on one axis. Our [ROI Calculator](/calculators/roi.html) computes it (and the raw profit) from any two numbers.

The blind spot is time. 10% in one month and 10% in five years produce identical ROI and could not be more different as investments. Any comparison of ROIs across different time horizons is a comparison of apples and calendar-affecting oranges — the number people reach for to fix this is the annualised return.

Annualised return: the time-normalised version

Annualising converts any holding period into the yearly rate that would produce the same result. The compound formula: annualised = (1 + ROI)^(1 ÷ years) − 1. A 20% ROI held for two years annualises to (1.20)^(0.5) − 1 ≈ 9.54% — much less impressive than the raw number, and honestly so. The same 20% in four months annualises to about 74%, which correctly screams 'either brilliant or luck'.

The simple shortcut — ROI ÷ years — is fine for rough work and materially wrong for anything with compounding or volatility. A 100% five-year return is not 20% a year; it's 14.87% compounded. Over long horizons the gap becomes enormous.

What counts as a good ROI?

Context first: it depends on asset class, timeframe and risk. Long-run anchors worth knowing: global equities have historically returned roughly 7–10% a year before inflation over multi-decade spans; investment-grade bonds roughly 2–5%; savings products track short rates (0–4% in recent cycles). Real estate blends yield plus appreciation, commonly 4–8% a year in many markets. A business project or marketing campaign is judged differently — agencies often target ROIs of 300%+ on ad spend precisely because campaigns are short and reinvestable.

The honest comparison is always risk-adjusted and inflation-aware: a reliable 6% beats a lottery-ish 15%, and 6% nominal with 4% inflation is roughly 2% real.

The costs people forget to subtract

Most self-reported ROIs are flattering because the denominator is too small. Include: platform and transaction fees, currency conversion spreads, taxes on gains, maintenance and insurance (physical assets), and the cost of your own time at a defensible hourly rate. For the ad-campaign example, 'invested' is not the ad invoice — it is the invoice plus agency fees plus the hours your team spent. The [ROI Calculator](/calculators/roi.html) takes whatever you feed it, so feed it true totals.

Also decide gross versus net deliberately: 'returned' should mean what you could actually put back in your pocket — after fees, and after selling costs if you'd have to exit.

Beyond ROI: IRR in one paragraph

When money goes in and out at different times — a rental property bought, improved, refinanced and sold — a single ROI loses meaning, because a euro invested early works harder than a euro invested late. The fix is IRR (internal rate of return), the discount rate that makes all flows net to zero; every spreadsheet has an IRR function. You do not need IRR to compare two same-length, single-investment bets — that is what plain ROI and our calculator are for.

A worked comparison

Investment A: 5,000 → 6,250 in 12 months. ROI 25%, annualised 25%. Investment B: 6,000 → 7,000 in 24 months. ROI 16.7%, annualised (1.1667)^0.5 − 1 ≈ 8.0%. A dominates B on every fair basis. Now flip B's timeframe to 6 months: ROI 16.7%, annualised ≈ 35.6% — suddenly B is the better engine. Same two numbers; the timeframe decides the verdict. This is exactly why raw ROI comparisons mislead, and why our [ROI Calculator](/calculators/roi.html) result should always be paired with its holding period.

Frequently asked questions

**Is ROI the same as annualised return?** No — ROI ignores time; annualised return normalises for it. **Can ROI exceed 100%?** Yes — it means you more than doubled your money. **What's a good ROI for a small business project?** Commonly 20%+ per project cycle, but it must beat your cost of capital and the risk-free alternative. **Where do I compute it?** The [ROI Calculator](/calculators/roi.html) for raw ROI, and the formula above for annualising. **Does ROI account for reinvestment?** No — that's precisely what IRR and compounding math add.