"What's the ROI?" is the most-asked question in any business or investment discussion. Return on Investment is a simple concept — what did you get back compared to what you put in — but the calculations and comparisons can get nuanced. Here's the practical guide.

The basic formula

ROI = (gain − cost) / cost × 100

Or: ROI = profit / investment × 100.

Express as a percentage.

Worked examples

Stock investment: bought $10,000 of stock; sold for $15,000. Gain $5,000.

  • ROI = 5000 / 10000 × 100 = 50%.

Real estate: bought $300k house, spent $20k on renovations, sold for $400k.

  • Total cost: $320k. Gain: $80k.
  • ROI = 80 / 320 × 100 = 25%.

Marketing campaign: spent $5k on ads, generated $25k in revenue with 30% gross margin.

  • Gross profit from campaign: $25k × 0.30 = $7,500.
  • ROI = (7500 − 5000) / 5000 × 100 = 50%.

Total ROI vs annualized ROI

Total ROI is over the full investment period. Annualized ROI normalizes for time:

Annualized ROI = (final / initial)^(1/years) − 1

Worked example: stock that gains 50% over 5 years.

  • Total ROI: 50%.
  • Annualized: (1.5)^(1/5) − 1 = 0.0845 = 8.45% per year.

Always annualize when comparing investments held for different periods.

Comparing investments fairly

Two investments:

  • A: $10k → $15k in 3 years. Total ROI 50%, annualized 14.5%.
  • B: $10k → $20k in 7 years. Total ROI 100%, annualized 10.4%.

B has higher total return, but A has better annualized return. Which is better?

It depends:

  • If you have time horizon of 7 years and B is risk-comparable, B's total return is what counts.
  • If you can reinvest A's returns at similar rates, A's annualized rate compounds and may beat B.

Common ROI mistakes

1. Ignoring time. 50% over 1 year ≠ 50% over 10 years.

2. Ignoring risk. 8% guaranteed isn't comparable to 12% risky. Always factor in risk.

3. Forgetting transaction costs. Trading commissions, real estate closing costs, mutual fund expense ratios all reduce ROI.

4. Ignoring taxes. Pre-tax ROI overstates actual gains. Capital gains tax (15–37% federal in U.S.) hits returns.

5. Confusing ROI with profit. A $1 million investment returning 5% (50k) is more profit than a $10k investment returning 100% ($10k). ROI matters more for decisions; profit matters more for cash flow.

ROI in marketing

Common marketing ROI calculations:

ROAS (Return on Ad Spend): revenue / ad spend.

  • $1 in ads → $5 in revenue → 5:1 ROAS.
  • Watch out: doesn't account for product margin.

True marketing ROI: profit / ad spend.

  • $5 revenue × 30% margin = $1.50 profit.
  • $1 ad spend → $1.50 profit → 50% ROI (or 1.5:1).

ROAS sounds good (5:1) but the actual ROI is 0.5:1 ($0.50 profit per $1 spent). The 5:1 doesn't mean profitable.

ROI in business investment

Investing in a project (new equipment, software, hire):

  1. Estimate annual cash flows generated.
  2. Calculate ROI: total cash flows / cost.
  3. Compare to alternative uses of capital (cost of capital).

If ROI exceeds cost of capital + required return, the project adds value. Otherwise, don't proceed.

NPV vs ROI

NPV (Net Present Value) is similar but accounts for the time value of money:

NPV = Σ (cash flow / (1 + discount rate)^year) − initial investment.

For investments with cash flows over many years, NPV is more rigorous than ROI. ROI doesn't distinguish "$50k in year 1" from "$50k spread over 10 years."

For quick decisions, ROI works. For high-stakes decisions, calculate NPV.

IRR (Internal Rate of Return)

IRR is the discount rate that makes NPV = 0. Often called "the project's effective annual return rate."

Use case: comparing investments with different cash flow patterns.

Example: investment A returns $1k/year for 10 years on $5k investment. Investment B returns $5k once at year 5 on $5k investment.

Total ROI is the same (100%). But IRR differs because of timing — A returns money sooner, has higher IRR.

ROI for stocks

Total ROI for stock investing:

  • Capital gain: (sale price − purchase price) / purchase price.
  • Plus dividends received.
  • Minus transaction costs.

Annualized: (final value / initial cost)^(1/years) − 1.

Compare to S&P 500 historical: ~9.5% annualized over long periods. Beat that and you're outperforming.

ROI for real estate

For investment property:

  • Cap rate: annual net operating income / property cost. Typically 4–10%.
  • Cash-on-cash return: annual cash flow / cash invested (after mortgage).
  • Total ROI: includes appreciation when sold.

Real estate often has 6–12% annual ROI (with leverage), more if appreciation is strong.

ROI for education

College: cost vs lifetime earnings premium.

  • Average bachelor's vs high school: ~$1M lifetime earnings difference.
  • Cost of degree: $50k (state school) to $300k (private).
  • ROI: highly variable by major and school.

STEM and business majors: high ROI. Liberal arts: variable. Specific schools matter (Ivy League ROI is amplified by network effects).

Calculate any ROI

Our ROI calculator handles total and annualized return from any cost and value pair. Useful for stocks, real estate, business investments, or comparing alternatives.