What Is ROAS? How to Calculate Return on Ad Spend

Updated October 2026 · 5 min read

ROAS (Return on Ad Spend) is the single most important metric for any paid advertising campaign. It tells you how much revenue you earn for every dollar you spend on ads. A ROAS of 4 means you earn $4 in revenue for every $1 spent — before costs.

The ROAS Formula

What Is a Good ROAS?

There is no universal "good ROAS" — it depends entirely on your profit margin. A 3× ROAS is excellent if you sell high-margin digital products; it is catastrophic if you sell physical goods at 25% margin.

Break-Even ROAS — The Number That Actually Matters

Break-even ROAS is the minimum ROAS at which your ads are neither profitable nor losing money. Anything above it is profit; below it, you are burning cash.

If your gross margin is 40%, you need a ROAS above 2.5× to profit from ads. A ROAS of 2.0× on that margin means you are losing money even though ad revenue exceeds spend.

ROAS vs ROI — What Is the Difference?

ROAS compares ad revenue to ad spend only, ignoring COGS and other costs. It is quick to calculate and useful for optimising individual campaigns.

ROI compares net profit (after all costs) to total investment. It is more accurate for business-level decisions but harder to calculate per campaign. Use ROAS for day-to-day campaign management, ROI for strategic budget decisions.

Why Your ROAS Can Look Great But Still Lose Money

Imagine an ad campaign: $1,000 spend → $3,000 revenue → ROAS = 3×. Looks profitable. But if COGS is $2,400 (80% of revenue): gross profit = $600 − $1,000 ad spend = −$400 loss. Always calculate break-even ROAS using your actual margin before scaling ad spend.