Worked through, end to end
Take the example the calculator loads by default: 2,500 ad spend, 9,000 revenue, 3,150 cost of goods.
| Metric | Calculation | Result |
|---|---|---|
| ROAS | 9,000 ÷ 2,500 | 3.60× |
| Net profit | 9,000 − 2,500 − 3,150 | 3,350 |
| Total cost | 2,500 + 3,150 | 5,650 |
| ROI | (3,350 ÷ 5,650) × 100 | +59.3% |
| Gross margin | ((9,000 − 3,150) ÷ 9,000) × 100 | 65.0% |
| Break-even ROAS | 9,000 ÷ (9,000 − 3,150) | 1.54× |
| ACOS | (2,500 ÷ 9,000) × 100 | 27.8% |
Reading it back: the campaign returns 3.60 of revenue per 1 spent, it needed only 1.54 to break even, and after paying for both the ads and the goods it left 3,350 in the business — a 59.3% return on the 5,650 that went out.
Why ROAS is written as a multiple
ROAS is usually written as 3.6× rather than 360% because it reads faster and because it is genuinely a ratio, not a gain. Both notations describe the same number: multiply by 100 to move between them. Where people go wrong is mixing notations in one conversation — "our ROAS is 360" is ambiguous, and someone always reads it as 3.6.
Break-even ROAS is the inverse of your margin
The formula above is written in terms of revenue and COGS because those are the numbers you have to hand. Algebraically it collapses to something simpler:
At a 40% gross margin, 1 ÷ 0.40 = 2.5×. At 65%, 1 ÷ 0.65 = 1.54× — exactly the figure in the table above. The two forms are identical; the calculator uses the revenue form so it keeps working even when you have not worked out your margin yet.
Why ROI divides by total cost, not by spend
A common shortcut is to divide profit by ad spend alone. That flatters the result, sometimes wildly, because it pretends the goods were free. ROI asks what you got back on everything you put in, so the denominator has to include the cost of goods as well as the media. In the worked example the difference is +59.3% (honest) versus +134% (flattering).
Edge cases the calculator handles
- Ad spend of zero. ROAS becomes undefined rather than infinite in any useful sense, so the tool prompts you for a spend figure instead of printing a meaningless number.
- COGS higher than revenue. Gross margin is negative, so no ROAS can rescue the campaign. Break-even shows as N/A with an explanation rather than a nonsense multiple.
- Everything at zero. The tool sits in a neutral state rather than reporting 0% returns on nothing.