Amazon advertising efficiency calculator
ACOS Calculator
Use this ACOS calculator to turn Amazon ad spend and attributed sales into ACOS, ROAS, TACoS, break-even ACOS, and contribution after ads. Enter one campaign, product group, and reporting window so the result stays comparable.
How to use the ACOS calculator
ACOS is meaningful only when spend and sales share the same campaign scope, currency, dates, and attribution window.
ACOS formula, ROAS, and TACoS
ACOS measures ad cost against attributed ad sales. ROAS reverses that relationship, while TACoS uses total sales to show how advertising affects the whole business.
ACOS = ad spend ÷ attributed ad sales × 100
Worked Amazon ACOS example
Suppose Amazon reports $1,000 in ad spend and $5,000 in attributed sales. Total sales are $8,000, and product plus other variable costs are $3,000.
The campaign spends 20 cents to generate each dollar of attributed sales. The modeled contribution after product, variable costs, and ads is $1,000 before fixed overhead and taxes.
| Ad spend | $1,000 |
|---|---|
| Attributed ad sales | $5,000 |
| ACOS | 20% |
| ROAS | 5.00× |
| TACoS | 12.5% |
| Contribution after ads | $1,000 |
ACOS vs ROAS vs TACoS
These metrics answer different questions. Use the same scope before comparing them across campaigns or products.
| Metric | Calculation | Best use |
|---|---|---|
| ACOS | Ad spend ÷ attributed ad sales | Ad cost efficiency inside Amazon Ads |
| ROAS | Attributed ad sales ÷ ad spend | Revenue returned per ad dollar |
| TACoS | Ad spend ÷ total sales | Advertising relative to the full sales base |
A campaign can improve ACOS while total sales or organic sales fall. Read ACOS with TACoS, contribution dollars, inventory, and attribution lag.
How to interpret your ACOS result
There is no universal good ACOS. Your break-even ACOS and growth objective set the useful range.
ACOS calculator limitations
This is a planning model based on the numbers you enter. It does not connect to Amazon Ads or validate an account.
- Amazon attribution windows can delay or change reported sales.
- ACOS excludes product and fulfillment costs unless you add them.
- Break-even ACOS is only as complete as the margin assumptions.
- TACoS needs total sales from the same period and product scope.
- Taxes, fixed overhead, inventory cash flow, and agency fees may need a separate review.
Metric references
Use first-party documentation when you align the calculator with account reporting.
ACOS calculator FAQ
How do I calculate ACOS?
Divide Amazon ad spend by attributed ad sales and multiply by 100. For example, $1,000 ÷ $5,000 = 20% ACOS.
What is a good ACOS on Amazon?
A good ACOS stays below your break-even ACOS while supporting growth, ranking, and inventory goals. The ceiling depends on product margin and costs.
How are ACOS and ROAS related?
They are reciprocal measures. ROAS is attributed sales divided by ad spend; ACOS is ad spend divided by attributed sales. A 25% ACOS equals 4.00× ROAS.
What is the difference between ACOS and TACoS?
ACOS uses attributed ad sales as the denominator. TACoS uses total sales, so it includes the full sales base and organic sales.
Does this ACOS calculator include Amazon fees?
Only when you enter them in other variable costs. Add referral, fulfillment, storage, discounts, refunds, or other costs in the same model.
Can I use the calculator for Sponsored Products?
Yes. Enter Sponsored Products spend and attributed sales from the same report window. It also works for Sponsored Brands when the scope matches.