ROI (Return on Investment)

Quality / Updated / COI

Quality

Reviewed

Updated

02/12/2026

Source

Citations & Trust

COI

none

TL;DR

ROI is a ratio that compares the net gain from an investment to its cost so you can judge efficiency.

Definition

Return on investment expresses how much value an initiative returns relative to what it costs, typically calculated as (gain minus cost) divided by cost. It is used to compare alternatives when time horizon, risk, and accounting rules are consistent. A good ROI definition specifies which costs and benefits count, the period of measurement, and the baseline used so decisions are not distorted by mismatched assumptions.

Decision impact

• It determines which projects clear a hurdle rate when budgets force tradeoffs.
• It changes stop-or-continue decisions by clarifying whether returns beat the target over the same period.
• It forces teams to define what costs and benefits are in scope, preventing misleading win claims.

Key takeaways

• Use a consistent time horizon and baseline when comparing ROI across options.
• Include total costs, not just obvious spend, so the ratio reflects real effort.
• Pair ROI with risk and payback to avoid favoring fragile or tiny wins.
• Document the formula, data sources, and assumptions so others can reproduce it.
• Recalculate after launch to validate forecasts and improve future estimates.

Misconceptions

• ROI is not the same as profit margin or revenue growth by itself.
• A higher ROI is not always better if the time horizon or risk differs.
• ROI is not objective unless the scope of costs and benefits is agreed first.

Worked example

A team must choose between two marketing campaigns. Campaign A is expected to generate $120,000 in margin on $60,000 of total cost, while Campaign B generates $90,000 on $30,000. ROI shows 100% for A and 200% for B, but the team also checks scale, risk, and capacity. They document the formula, include staff time in costs, and decide to run B first while reserving budget for A if the first test confirms assumptions.

Citations & Trust

• Contemporary Mathematics 6.7 Investments (OpenStax)