What Is Break-even ACOS?
Break-even ACOS is the advertising cost of sale at which you make zero profit on a unit. Every Amazon PPC decision starts here.
Definition
ACOS stands for Advertising Cost of Sale. It measures how much you spend on advertising for every dollar of ad-attributed revenue. An ACOS of 25% means you spent $0.25 in ads to generate $1.00 in sales.
Break-even ACOS is the specific ACOS percentage at which your ad spend exactly consumes your profit margin, leaving you with zero net profit on each unit sold through ads. Any ACOS below break-even is profitable. Any ACOS above it means you are losing money on every ad-driven sale.
Break-even ACOS = Pre-ad Profit Margin (%)
Where pre-ad profit margin is calculated as:
Pre-ad Margin = (Selling Price − COGS − Referral Fee − FBA Fee − Storage − Other Costs) ÷ Selling Price × 100
The result is a percentage. That percentage is your break-even ACOS. Keep your campaign ACOS below this number to stay profitable.
Worked Example
You sell a yoga mat for $29.99. Your costs break down as follows:
- COGS: $6.00
- Referral fee (15%): $4.50
- FBA fee: $5.40
- Storage per unit: $0.20
- Inbound shipping per unit: $1.10
- Other costs: $0.30
Total non-ad costs: $17.50
Pre-ad profit: $29.99 − $17.50 = $12.49
Pre-ad margin: $12.49 / $29.99 = 41.6%
Your break-even ACOS is 41.6%. As long as your PPC campaigns run at an ACOS below 41.6%, every ad sale generates profit. If your ACOS climbs above 41.6%, you are paying more in ads than you have margin to cover.
Break-even ACOS Across Different Margin Scenarios
Break-even ACOS varies significantly by product economics. Here are five common scenarios to see how margin drives your safe bidding range.
| Product Type | Selling Price | Total Non-ad Costs | Pre-ad Margin | Break-even ACOS | Suggested Target ACOS |
|---|---|---|---|---|---|
| Low-margin commodity | $14.99 | $13.19 | 12% | 12% | 7–9% |
| Mid-range kitchen gadget | $24.99 | $17.49 | 30% | 30% | 18–22% |
| Standard private label | $29.99 | $17.50 | 42% | 42% | 25–32% |
| Premium supplement | $49.99 | $22.50 | 55% | 55% | 35–45% |
| High-end electronics accessory | $79.99 | $27.99 | 65% | 65% | 45–55% |
Notice how a raw ACOS of 35% could mean very different things: it is unprofitable for the commodity product but highly profitable for the supplement. Always evaluate ACOS relative to your own break-even, not an industry average.
Why Break-even ACOS Matters
Setting Bid Strategy
Without knowing your break-even ACOS, you are guessing at bids. If your break-even is 41.6% and your current ACOS is 30%, you have room to increase bids to gain more impressions and sales while staying profitable. If your ACOS is 50%, you need to cut bids or optimize targeting immediately.
Evaluating Campaign Performance
A 35% ACOS might sound bad compared to a competitor bragging about 15%. But if your break-even is 42% and theirs is 18%, you are actually more profitable on ad spend than they are. Break-even ACOS provides the context that raw ACOS numbers lack.
Launch vs. Maintenance Phases
During a product launch, many sellers intentionally run above break-even ACOS to gain ranking and reviews. This is a deliberate investment. Knowing your break-even tells you exactly how much you are subsidizing each sale and helps you set a timeline to bring ACOS back below break-even.
ACOS (Advertising Cost of Sale) divides ad spend only by ad-attributed revenue. It measures the efficiency of your paid campaigns in isolation.
TACoS (Total Advertising Cost of Sale) divides your total ad spend by all revenue—organic and paid combined. TACoS gives a broader view because it captures the organic sales lift that PPC helps generate. A healthy TACoS is usually 8–15% for established products.
Break-even ACOS is calculated against ACOS, not TACoS. Using TACoS to evaluate whether you are above or below break-even will give you a falsely optimistic picture during the early weeks of a launch when organic sales are low.
How to Use Break-even ACOS in Practice
- Calculate it per SKU. Different products have different margins and therefore different break-even ACOS values. A high-margin supplement might have a break-even of 55%, while a low-margin commodity product sits at 12%. You cannot use a single target across your catalog.
- Set your target ACOS below break-even. Most sellers set a target ACOS that is 5–15 percentage points below break-even. This builds in a profit buffer. If your break-even is 40%, a target of 25–30% is reasonable.
- Recalculate when costs change. If your supplier raises prices, your COGS goes up, your margin shrinks, and your break-even ACOS drops. If Amazon increases FBA fees, the same thing happens. Review quarterly at minimum.
- Use it to kill unprofitable campaigns. Any campaign consistently running above break-even ACOS for more than 2–3 weeks (outside of a launch) should be paused, restructured, or have its bids reduced.
Use the Break-even ACOS Calculator to enter your selling price and costs and instantly see your break-even percentage, suggested target ACOS, and profit per unit at various ACOS levels. No spreadsheet required.
Quick Reference
- Break-even ACOS = your pre-ad profit margin as a percentage
- Below break-even ACOS = profitable ad sales
- Above break-even ACOS = losing money on each ad sale
- Calculate per SKU, not across your entire catalog
- Recalculate whenever your costs or selling price change