How to Use This Tool
Separate incremental revenue from revenue that the control would have produced anyway. Calculate incremental ROAS from test and control spend and revenue instead of crediting the campaign with baseline sales.
The decision this tool supports
Ordinary ROAS credits advertising for baseline demand and can make a campaign look profitable when the incremental lift is weak. This page keeps the decision bounded to incremental roas and the supporting outputs shown beside it. Incremental ROAS does not import an account, infer a market rate, or silently substitute an industry average.
Inputs and units
The Incremental ROAS calculation uses Test spend, Test revenue, Control spend, Control revenue. Keep all money values in one currency and all time, distance, mass, energy or volume entries in the unit printed beside the field. Mixing Incremental ROAS scopes can produce a plausible number with the wrong meaning.
- Test spend is entered in currency.
- Test revenue is entered in currency.
- Control spend is entered in currency.
- Control revenue is entered in currency.
Formula and worked check
Incremental ROAS = (test revenue − control revenue) ÷ (test spend − control spend). Test spend/revenue of $10,000/$18,000 versus $8,000/$12,000 control yields $6,000 incremental revenue on $2,000 incremental spend, or 3.00:1. The Incremental ROAS default is an executable known-answer case, not a benchmark or recommendation. Change one input and verify that the direction of incremental roas still matches the stated relationship.
How to interpret the result
Compare incremental ROAS with an incremental break-even threshold based on contribution, not with gross-revenue ROAS from a different attribution model. The additional Incremental ROAS outputs expose the denominator, comparison, capacity or reverse value needed to audit the primary result instead of presenting one unexplained number.
Assumptions
- Test and control use comparable audiences and windows.
- Revenue definitions and attribution cutoffs match.
- Incremental spend must be positive.
Save the Incremental ROAS input values and date with any material decision. A later Incremental ROAS rerun is reproducible only when the same assumptions and units are available.
Limitations and safety boundary
The arithmetic does not prove randomization, incrementality, attribution quality, equal audiences or statistical significance. Incremental ROAS is an estimate and cannot replace a contract, local code, licensed professional, calibrated measurement, lender statement or platform report where one governs the decision.
Source and privacy
The Incremental ROAS definition or rule was checked against Google Ads Help — About conversion values on 2026-08-26. Recheck Google Ads Help — About conversion values when a specification or policy behind Incremental ROAS can change. Incremental ROAS arithmetic runs in this browser tab; ecech does not receive the values through a calculation API.
Sources & assumptions
Tool Spec v2 · verified 2026-08-26. Platform rules and fees can change; the editable inputs remain authoritative for your account.
Official references
- Google Ads Help — About conversion values (checked 2026-08-26)
Model assumptions
- Test and control use comparable audiences and windows.
- Revenue definitions and attribution cutoffs match.
- Incremental spend must be positive.
- The arithmetic does not prove randomization, incrementality, attribution quality, equal audiences or statistical significance.
