What return on ad spend measures
ROAS compares revenue attributed to advertising with advertising spend. A ratio of three means three units of revenue were attributed for every unit spent. The percentage expression multiplies the ratio by one hundred, so a three-times return is three hundred percent. Both describe revenue efficiency rather than profit. The basic calculation is useful for comparing campaigns only when revenue, spend, attribution and time windows have sufficiently consistent definitions.
The formula
Keep currency, units and time periods consistent. Percentage inputs use percentage points (enter 5 for 5%). Results are rounded only for display; tiny nonzero values may use scientific notation. Undefined ratios are shown as unavailable.
A campaign that generates $3,500 attributed revenue from $1,000 spend returns 3.50x ROAS. A 4.00x goal would require $4,000 revenue, leaving a $500 gap. At a 40% pre-ad contribution margin, the existing revenue produces $1,400 contribution before ads and $400 after ads, before fixed overhead.
Keep attribution and reporting periods aligned
Enter ad spend and attributed revenue from compatible periods. A sale reported today may have followed a click from an earlier period, and a platform can attribute revenue differently from your store analytics. Multiple platforms may each claim a role in the same order. This calculator does not deduplicate those claims or determine incrementality. Review the source data before treating a high reported ratio as evidence that an advertising channel caused all the revenue assigned to it.
Use a selected goal for context
Goal mode calculates the revenue required to reach a target ROAS at current spend. It also calculates the maximum spend supported by current revenue at that target and the remaining revenue gap. A negative gap means current revenue already exceeds the required amount. These are rearrangements of the same ratio, not independent performance predictions. The target is supplied by you, because an appropriate revenue multiple depends on the contribution available in your own business.
Translate the ratio into contribution
Advanced mode multiplies revenue by pre-ad contribution margin and subtracts ad spend. This estimates the contribution remaining after ads, before fixed overhead and any costs omitted from the margin. It also shows the reciprocal-margin break-even ROAS. A campaign can have an apparently strong revenue ratio but negative contribution if product and selling costs consume too much revenue. Conversely, a lower ratio can leave positive contribution for a high-margin order mix.
Target post-ad margin and feasibility
Reserving a post-ad profit margin reduces the share of revenue available for advertising. The required ROAS is the reciprocal of contribution margin minus the selected post-ad margin. If the desired post-ad margin equals or exceeds pre-ad contribution, no positive ad-spend share remains and a finite target cannot be calculated. The unavailable result is meaningful: it identifies an incompatible combination of costs and goal rather than a calculation failure.
ROAS, ROI and practical monitoring
Return on investment generally compares a profit or gain with the investment that produced it. ROAS uses attributed revenue in its numerator and ad spend in its denominator, so the two are not interchangeable. Monitor acquisition cost, order contribution, refunds and customer mix alongside the reported ratio. Use Break-Even ROAS to build the contribution margin from costs, Maximum CPA to translate it into order-level spending room, and Ecommerce Profit to include a monthly fixed-cost allocation.
Method and reference sources
Method and content checked 2026-09-20. These sources provide background, not endorsement or professional certification. The formula and limitations above define this calculator.
- Google Ads — ROAS ratio and percentageROAS compares attributed conversion value with advertising cost. A 5× ratio equals 500%; it is not profit margin.
- SBA — Break-even pointContribution, variable costs and fixed-cost break-even context; tool-specific extensions are explained above.
Frequently asked questions
Does a 3x ROAS mean a profit of three times my spend?
No. It means three units of attributed revenue for each unit of ad spend. Product costs, fulfillment, fees, refunds and overhead still affect profit.
What is a worked example for ROAS?
A campaign that generates $3,500 attributed revenue from $1,000 spend returns 3.50x ROAS. A 4.00x goal would require $4,000 revenue, leaving a $500 gap. At a 40% pre-ad contribution margin, the existing revenue produces $1,400 contribution before ads and $400 after ads, before fixed overhead.