About the ROI Calculator
An ROI (Return on Investment) calculator measures the gain or loss on an investment relative to its cost — a single, comparable percentage that lets you compare opportunities across categories. ROI's simplicity is its strength and its weakness: it doesn't account for time, risk, or cash-flow timing. For one-time, similar-duration comparisons it's genuinely useful; for evaluating compound returns or long-term investments, IRR and CAGR are usually more honest measures.
The basic formula and what it doesn't tell you
ROI = (final value − initial cost) / initial cost. A $10,000 investment that grows to $13,500 has an ROI of 35%. The formula treats every dollar of gain identically regardless of when it arrived, how long the investment was held, or how much risk was taken to achieve it.
This makes ROI great for quick, intuitive comparisons of similar-duration projects: "Marketing campaign A returned 35%; campaign B returned 22%; A wins." It makes ROI misleading for time-sensitive comparisons: a 35% ROI over 5 years is dramatically different from a 35% ROI over 6 months — the headline number is the same.
ROI vs. CAGR vs. IRR — when each is appropriate
ROI: total gain as a percentage of initial cost. Best for one-time, single-period evaluations. The simplest measure.
CAGR (compound annual growth rate): the equivalent constant annual rate that produces the observed total return. Best for multi-period investments without intermediate cash flows. Annualizes the return for cross-period comparisons.
IRR (internal rate of return): the discount rate that makes the net present value of all cash flows zero. Best for investments with multiple cash flows over time (rental properties, business ventures, capital projects). Handles inflows and outflows at different times correctly, where ROI cannot.
When in doubt: ROI for a quick check, CAGR for time-adjusted compound growth, IRR for irregular cash flow patterns. The wrong measure can make a worse investment look better than a better one.
Beyond the formula: what the numerator should include
For a real estate investment, the gain isn't just appreciation — it's appreciation plus rental income minus expenses (mortgage interest, property tax, insurance, maintenance, vacancies). Investors who compute ROI on appreciation alone systematically overestimate real-estate returns.
For business investments, the relevant return includes operating cash flows (positive or negative) over the holding period, not just terminal value. A business that broke even operationally and sold for the same price you paid has a 0% ROI, regardless of the operational risks taken along the way.
Always include all costs in the denominator (closing costs, transaction fees, opportunity cost of inventory or working capital) and all returns in the numerator (operating cash flows, dividends, terminal value, tax benefits). ROI on a partial picture is worse than no ROI at all.
Marketing ROI and the attribution problem
Marketing ROI = (revenue attributable to campaign − campaign cost) / campaign cost. The hard part is the "attributable to." Multi-touch attribution, view-through credit, organic vs. paid distinctions, and customer lifetime value all change the numerator dramatically.
Treat marketing ROI as directional. A campaign with a clearly negative ROI (cost more than it brought in) is failing. A campaign with a 200% ROI under one attribution model and 50% under another is genuinely uncertain. Iterating on attribution methodology can change the answer entirely without changing the underlying campaign.
Formula
- final value = Total return: cash flows received plus terminal value
- initial cost = Total invested capital, including all transaction costs
- ROI = Expressed as a percentage; can be negative (a loss)
Worked examples
Stock investment
Buy 100 shares at $50, sell at $65. Initial cost $5,000. Final value $6,500. ROI: ($6,500 − $5,000) / $5,000 = 30%. If held over 5 years, CAGR = (6500/5000)^(1/5) − 1 ≈ 5.4% — a more useful figure for cross-investment comparison.
Real estate (full picture)
Buy rental for $200,000 + $10,000 closing = $210,000 in. Held 5 years: $25,000 net rental income (after expenses, mortgage interest), sold for $260,000 net of selling costs. Total return: $50,000 (sale gain) + $25,000 (operating) = $75,000. ROI: $75,000 / $210,000 = 35.7%. CAGR: (285/210)^(1/5) − 1 ≈ 6.3%.
Business marketing campaign
Campaign cost: $20,000. Attributable revenue: $80,000. Gross ROI: ($80,000 − $20,000) / $20,000 = 300%. Add product cost-of-goods (say 60% of revenue): contribution margin is $32,000. ROI on contribution: ($32,000 − $20,000) / $20,000 = 60%. The same campaign goes from "4× return" to "1.6× return" depending on which version of "return" you use.
Frequently asked questions
What's a good ROI?
Highly context-dependent. For stock-market investments over a year: 7–10% is roughly the historical average. For real estate (including rental income): 8–12% leveraged returns are typical for stable markets. For high-risk venture capital: 30%+ on successful investments is needed because most fail. There's no universal benchmark — compare to the realistic alternatives for your specific risk and time horizon.
What's the difference between ROI and ROE?
ROI is return relative to total invested capital. ROE (return on equity) is return relative to shareholders' equity — what's left after debt. For leveraged investments, ROE can be much higher than ROI because borrowed money amplifies returns (and losses). Both are useful for different questions.
Can ROI be negative?
Yes — if final value is less than initial cost. A $10,000 investment now worth $7,500 has an ROI of −25%. Negative ROI signals a loss; magnitude indicates how severe.
Does ROI account for time?
No — that's its main limitation. A 30% ROI over 1 year and a 30% ROI over 10 years look identical. For time-adjusted comparisons, use CAGR (compound annual growth rate) or IRR (internal rate of return) instead. ROI is most appropriate for similar-duration comparisons.
Should I use ROI or NPV for project evaluation?
NPV (net present value) is generally more rigorous for project evaluation because it directly accounts for the time value of money and uses an explicit cost of capital. ROI is simpler and faster. For a quick check, ROI works; for high-stakes capital allocation decisions, NPV plus IRR plus payback period together give a fuller picture.
What costs should be in the ROI denominator?
All costs of the investment: purchase price, transaction fees, closing costs, opportunity cost of capital tied up, ongoing expenses if not netted into the numerator. Excluding costs makes ROI look better than it is — a common mistake especially in real estate (forgetting closing costs) and marketing (forgetting overhead allocation).
Related calculators
Concepts
Sources & methodology
- Investor.gov (SEC) — Understanding return calculations — source