ACoS to ROAS Calculator

Simplify Ad Metrics—Instantly Convert ACoS ↔ ROAS or calculate directly from spend & return.
Get clarity on how much you’re really spending versus earning on ads.

ACoS to ROAS

ACoS (%)

ROAS (%): -

ROAS to ACoS

ROAS (%)

ACoS (%): -

What Are ACoS & ROAS?

Advertising metrics can be confusing when different platforms use different terms. Two of the most common are ACoS (Advertising Cost of Sale) and ROAS (Return on Ad Spend). They describe the same relationship—ad spend compared to revenue—but framed from opposite perspectives.

ROAS (Return on Ad Spend) = Revenue ÷ Ad Spend. If you spend $100 on ads and make $500 in sales, your ROAS is 5.0.
ACoS (Advertising Cost of Sale) = (Ad Spend ÷ Revenue) × 100. If you spend $100 and make $500, ACoS is 20%.

Both are useful, but they emphasize different sides of the equation.

ACoS ↔ ROAS Conversion Formulas

Because ACoS and ROAS are inverses of each other, you can convert instantly:

ROAS = 1 ÷ ACoS (decimal form)
ROAS (%) = 100 ÷ ACoS (%)
ACoS = 1 ÷ ROAS (decimal form
ACoS (%) = 100 ÷ ROAS (%)

Why Both Metrics Matter

ROAS is a growth-focused metric. It tells you how much return you are generating per dollar of ad spend. High-growth marketers love ROAS because it emphasizes scale—more return for each dollar in.

ACoS, on the other hand, is cost-focused. It tells you how much of your revenue is eaten by advertising. Efficiency-minded operators prefer ACoS because it emphasizes controlling spend and protecting margins.

Worked Examples

Example 1: Converting ACoS to ROAS
Suppose your ACoS is 25%. To convert, divide 100 by 25. ROAS = 4. This means for every $1 you spend, you earn $4 in sales.

Example 2: Converting ROAS to ACoS
Suppose your ROAS is 5. To convert, divide 100 by 5. ACoS = 20%. This means advertising takes up 20% of your sales.

Example 3: Direct from Spend and Revenue
If you spend $200 on ads and generate $1,000 in revenue: ROAS = 1000 ÷ 200 = 5. ACoS = 200 ÷ 1000 = 20%.

Quick Comparison Table

Scenario	ACoS	ROAS
Spend $100, Revenue $400	25%	4.0
Spend $250, Revenue $750	33.3%	3.0
Spend $500, Revenue $1000	50%	2.0
Spend $100, Revenue $200	50%	2.0
Spend $100, Revenue $100	100%	1.0

When to Use ACoS vs ROAS

Use ACoS when you want to benchmark efficiency. Amazon sellers and marketplace operators often focus on ACoS to understand what % of their revenue is consumed by ads.
Use ROAS when you want to understand return. E-commerce marketers scaling on Facebook, Google, or TikTok often prefer ROAS because it frames results as a multiple of spend.

In practice, you should monitor both. A low ACoS might look efficient but could limit scale. A high ROAS might look great but could hide that too much of your revenue is being reinvested into ads.

Advanced Considerations

Break-Even Points: Knowing your product margins allows you to calculate a break-even ACoS or ROAS. For example, if your margin is 40%, your break-even ACoS is 40%. Any ACoS below that is profitable.
Lifetime Value (LTV): Sometimes you can accept a higher ACoS or lower ROAS in the short term if your customer base has strong repeat purchase behavior.
Channel Mix: Different platforms report differently. Amazon typically shows ACoS, while Google and Meta focus on ROAS. Use conversion formulas to normalize across channels.
Blended Metrics: Many operators now blend ad spend across channels and calculate blended ROAS/ACoS for a holistic view.

FAQ

Which metric should I report to executives?

Both. ROAS is easier for non-finance teams to interpret. ACoS is critical for finance and operations. Presenting both avoids misinterpretation.

Why does Amazon use ACoS while Google uses ROAS?

Amazon frames advertising as a cost of sales. Google frames it as a return. Each aligns with how the platform monetizes and communicates value.

Is higher ROAS always better?

Not necessarily. A very high ROAS may mean you are underspending and missing out on growth opportunities. Balance efficiency with scale.

Ready to master your ad metrics? Use the ACoS ↔ ROAS Calculator to instantly convert between the two or compute directly from spend and revenue.

Break Even ROAS Calculator

Margin Vs Markup Calculator