ROAS & Ad Spend Calculator
Return on ad spend, cost per customer, break-even ROAS, and the profit left after the ad bill — computed on your own numbers. The honest view most ad dashboards hide.
Do your ads actually make money?
Return on ad spend looks great until margin enters the picture. See your ROAS, cost per customer, and the profit left after the ad bill.
ROAS (Return on Ad Spend) is calculated as Revenue from Ads divided by Cost of Ads. Mathematically: ROAS = Revenue / Cost. For example, if you spend $1,000 on ads and generate $4,000 in revenue, your ROAS is 4.0 (or 4:1). Cost per Customer (CPCust) is Total Ad Spend divided by Number of New Customers Acquired: CPCust = Ad Spend / Customers. Break-Even ROAS is the minimum ROAS needed to cover product costs and ad spend, calculated as 1 / (1 - Gross Margin %). For instance, with a 50% gross margin, Break-Even ROAS = 1 / (1 - 0.50) = 2.0. Profit Left is Revenue minus Ad Spend minus Cost of Goods Sold (COGS): Profit = Revenue - Ad Spend - (Revenue * (1 - Gross Margin)). This metric reveals actual net profit after ad costs, unlike standard ROAS which ignores product costs. These formulas are derived from basic profit accounting: revenue must exceed the sum of ad costs and variable product costs to yield profit. The calculations are essential because they separate vanity metrics (high ROAS with thin margins) from true profitability, giving a honest view of ad performance.
E-commerce Store with 40% Margin
An e-commerce store spends $2,000 on Facebook ads, generating $10,000 in revenue and acquiring 100 new customers. Gross margin is 40% (0.40). ROAS = $10,000 / $2,000 = 5.0. Cost per Customer = $2,000 / 100 = $20. Break-Even ROAS = 1 / (1 - 0.40) = 1.67. Profit = $10,000 - $2,000 - ($10,000 * 0.60) = $10,000 - $2,000 - $6,000 = $2,000. The store makes $2,000 profit after ad costs and product costs.
SaaS Company with 80% Margin
A SaaS company spends $5,000 on LinkedIn ads, generating $25,000 in subscription revenue and acquiring 50 customers. Gross margin is 80% (0.80). ROAS = $25,000 / $5,000 = 5.0. Cost per Customer = $5,000 / 50 = $100. Break-Even ROAS = 1 / (1 - 0.80) = 5.0. Profit = $25,000 - $5,000 - ($25,000 * 0.20) = $25,000 - $5,000 - $5,000 = $15,000. The company makes $15,000 profit, but note that break-even ROAS is 5.0, meaning any ROAS below that would lose money despite a high nominal ROAS.
Local Service Business with 60% Margin
A local plumber spends $500 on Google Ads, generating $2,000 in service revenue and acquiring 10 customers. Gross margin is 60% (0.60). ROAS = $2,000 / $500 = 4.0. Cost per Customer = $500 / 10 = $50. Break-Even ROAS = 1 / (1 - 0.60) = 2.5. Profit = $2,000 - $500 - ($2,000 * 0.40) = $2,000 - $500 - $800 = $700. The plumber earns $700 profit, with a comfortable margin above break-even.
A 'good' ROAS depends heavily on your gross margin and business model. Generally, a ROAS above your break-even ROAS means you're profitable; below it means you're losing money on each sale. For low-margin businesses (e.g., 10-20% gross margin), break-even ROAS can be 5-10, making high ROAS essential. For high-margin businesses (e.g., 70-90% gross margin), break-even ROAS is lower (1.1-1.4), so even modest ROAS can be profitable. Focus on profit left, not just ROAS; a high ROAS on low margin may yield less profit than a moderate ROAS on high margin. Cost per customer should be compared to customer lifetime value (LTV); a high cost per customer is acceptable if LTV is high. Avoid comparing your ROAS to arbitrary 'industry averages' without considering margin differences. Trends matter: improving ROAS over time is better than a static number. Always include all ad costs (platform fees, agency fees) and attribute revenue accurately (last-click vs. multi-touch) to avoid misleading results.
A common mistake is using ROAS without considering gross margin, leading to false confidence. For example, a 3:1 ROAS on a 20% margin product means you lose 20% on every sale after product costs. Another error is attributing all revenue to ads when some sales would have occurred organically (overattribution). Edge cases: negative ROAS (spending more than revenue) indicates immediate loss; infinite ROAS occurs if ad spend is zero but revenue is attributed, which is unrealistic. Also, forgetting to include non-ad costs like shipping or returns in gross margin can inflate profit calculations. Lastly, using ROAS for long sales cycles (e.g., B2B) without adjusting for time lag misrepresents performance.
- Return on Ad Spend (ROAS)
- A metric measuring revenue generated per dollar spent on advertising, calculated as revenue divided by ad cost.
- Cost per Customer (CPCust)
- The average ad spend required to acquire one new customer, calculated as total ad spend divided by number of new customers.
- Break-Even ROAS
- The minimum ROAS needed to cover both ad costs and product costs, calculated as 1 divided by (1 minus gross margin).
- Gross Margin
- The percentage of revenue remaining after subtracting the cost of goods sold, expressed as a decimal (e.g., 0.50 for 50%).
- Profit Left
- The net profit after subtracting ad spend and cost of goods sold from revenue, representing actual earnings from the ad campaign.
How do I calculate ROAS if I have multiple ad platforms?
Sum all ad spend across platforms and all attributed revenue, then divide total revenue by total spend.
What is a good ROAS for a new business?
It depends on your margin, but aim for at least your break-even ROAS; many start with 2-3x and optimize upward.
Why is profit left different from ROAS?
ROAS ignores product costs, while profit left subtracts both ad spend and cost of goods sold, giving true net profit.
How do I handle returns or refunds in this calculator?
Use net revenue (after returns) and adjust gross margin to account for refund costs; otherwise, profit will be overstated.
Can I use this calculator for offline ads?
Yes, as long as you can accurately attribute revenue and costs to the ad campaign.
What if my ad spend is zero but I still get sales?
ROAS becomes undefined (division by zero); focus on organic revenue separately.
How often should I recalculate these metrics?
At least monthly, or after each campaign, to track trends and adjust budgets.
What is a common mistake with break-even ROAS?
Using gross margin that excludes all variable costs (e.g., shipping, transaction fees) leads to an overly optimistic break-even.
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