Amazon ACoS and TACoS Calculator
Calculate Amazon-style ACoS, TACoS and break-even advertising metrics from your own sales figures — independent of and not endorsed by Amazon.
25%ACoS
TACoS 10%, ROAS 4×
| Metric | Value |
|---|---|
| ACoS | 25% |
| TACoS | 10% |
| ROAS | 4× |
| Organic residual | $600 |
| Break-even ACoS | 40% |
| Unit contribution before ads | $20 |
| CPA (per order) | $20 |
ACoS versus TACoS
How this is calculated
ACoS% = 100 × adSpend / attributedSales | TACoS% = 100 × adSpend / totalSales | ROAS = attributedSales / adSpendACoS measures ad efficiency against only the sales advertising is credited with. TACoS measures ad spend against your entire business's sales — useful for seeing how advertising affects the whole account, not just advertised listings.
Worked example
Ad spend $100, attributed sales $400, total sales $1,000: ACoS = 100 × 100 / 400 = 25%; TACoS = 100 × 100 / 1000 = 10%; ROAS = 400 / 100 = 4×.
Attribution windows and aligned revenue
The organic residual (total sales − attributed sales = $600 in the example) is only meaningful when both figures share the same date range, revenue basis and attribution definition. A negative residual is flagged as a likely mismatch — never silently clamped to zero.
Break-even ACoS and CPA
Break-even ACoS% = 100 × unit contribution before ads / unit revenue. With $50 unit revenue and $30 unit costs: break-even ACoS = 40%, and a one-unit order's CPA allowance is its full $20 contribution. Product price is never treated as average order value for multi-item orders.
Post-ad contribution
Total contribution should use all matching sales and costs for the period, not only the advertised units — comparing ACoS/TACoS alongside your actual per-unit economics gives a fuller efficiency picture than ad metrics alone.
- Compatible time windows
- The organic residual requires matching date range, revenue basis and attribution definition.
- No AOV assumption
- CPA requires an explicit order/unit count — product price is never treated as AOV.
Questions
Can ACoS and TACoS use different date ranges?
ACoS and TACoS can technically be calculated over any date range you choose, but the organic-sales residual (total sales minus ad-attributed sales) is only meaningful when both figures come from the same compatible date range, revenue basis and attribution definition. Mixing windows produces a residual that looks like data, but isn't comparable — this tool flags a negative residual as a likely mismatch rather than treating it as real negative organic sales.
Why can attributed sales exceed total sales?
It usually signals incompatible reporting — different date ranges, different revenue definitions (gross vs. net), or attribution windows that count a sale outside the period you're comparing against. It is not something this tool auto-corrects; it's shown as a flagged discrepancy so you can go check your source reports.