Amazon fees in this calculation
Presets reflect typical Amazon economics (verified 2026-07-23) — adjust every field to your actual numbers. Estimates only.
| Referral fee Most categories; 8% for some (verify yours) | ~15% of price |
| FBA fulfillment Size/weight tiered — this preset uses $5.50 | $3–$7+ per unit |
| Inbound shipping Amortize freight-to-FBA into your unit COGS | often in COGS |
Worked examples
Standard-size FBA product
| Selling price | $30.00 |
| All per-order costs | $19.00 |
| Contribution margin | $11.00 |
| Break-even ACOS | 36.7% |
Referral 15% ($4.50) + FBA $5.50 — Amazon takes a third of the price before ads.
Higher-priced, light item
| Selling price | $80.00 |
| All per-order costs | $40.20 |
| Contribution margin | $39.80 |
| Break-even ACOS | 49.7% |
Referral scales with price ($12) but FBA stays weight-based — margins widen.
Break-even ACOS by margin — quick reference
| Gross margin (after fees) | Break-even ACOS |
| 20% | 20% |
| 25% | 25% |
| 33% | 33% |
| 40% | 40% |
| 50% | 50% |
| 60% | 60% |
Frequently asked questions
What is a good ACOS on Amazon?
Any ACOS below your break-even ACOS is profitable on the order itself. There is no universal "good" number: a product keeping 37% margin after fees breaks even at 37% ACOS, one keeping 20% breaks even at 20%. Compare campaigns to your own ceiling, not to category averages.
Does break-even ACOS include the Amazon referral fee?
Yes — that is the point of calculating it after fees. The referral fee (15% for most categories) and the FBA fulfillment fee come out of your margin before a single ad dollar, so both must be in the calculation or your "break-even" will quietly lose money.
What is the difference between ACOS and TACOS?
ACOS is ad spend divided by ad-attributed sales. TACOS (total ACOS) divides ad spend by ALL sales, organic included. This calculator gives you the per-order ACOS ceiling; TACOS is a portfolio metric for judging how ads lift organic rank over time.
How do I convert break-even ACOS to ROAS?
ROAS = 1 ÷ ACOS. A 37% break-even ACOS equals a 2.7× break-even ROAS. Amazon dashboards speak ACOS; Google and Meta speak ROAS — same limit, inverted.