Are your ads making money or burning cash?
A 4x ROAS can still lose money. The only way to know if ads are profitable is to check ROAS against gross margin. Here's how — with the calculators, worked example, and decision checklist.
Is my current ROAS above my break-even ROAS?
What is my true customer acquisition cost including all channels?
Can my LTV justify a higher CAC to grow faster?
Which channel has the lowest cost per qualified lead?
What happens to ROI if my conversion rate improves by 0.5%?
What ad spend is needed to hit my revenue target at current ROAS?
Recommended tools
Calculators for this decision
ROAS Calculator
Calculate return on ad spend and revenue efficiency.
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Return on ad spend and break-even ROAS — and whether a given ROAS is actually profitable at your gross margin.
Customer Acquisition Cost Calculator
Calculate CAC from marketing spend and new customers.
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Blended CAC from total marketing and sales costs — not just ad spend.
Cost Per Lead Calculator
Calculate CPL and lead volume efficiency from campaign spend.
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CPL by channel, and effective CAC from CPL once lead-to-customer conversion rate is factored in.
Conversion Rate Calculator
Calculate conversion rate from visitors, leads, trials, or purchases.
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CVR impact on revenue — how a 0.5% conversion improvement changes total return at constant spend.
Ad Spend Calculator
Plan ad spend from revenue goal, conversion rate, and average order value.
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Required ad budget to hit a revenue target given current ROAS and conversion data.
Marketing Budget Calculator
Plan marketing budget across channels and revenue goals.
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Total marketing budget allocation across channels from ROAS targets and revenue goals.
Practical guide
Why ROAS alone does not tell you if ads are profitable
Return on ad spend (ROAS) measures revenue generated per pound spent on ads. A 4x ROAS means you generated £4 in revenue for every £1 in ad spend. But ROAS ignores gross margin. If your product costs 70p to make and deliver for every £1 of revenue (30% gross margin), your break-even ROAS is 1 ÷ 0.30 = 3.33x. A 4x ROAS with 30% gross margin leaves only thin margin after ad spend — and nothing covers your fixed overheads, team, or profit.
Break-even ROAS = 1 ÷ Gross Margin. At 50% gross margin, break-even ROAS is 2x. At 25%, it is 4x. At 20%, it is 5x. If your current ROAS is below your break-even ROAS, ads are losing money at the gross margin level — before any overhead is counted.
Customer acquisition cost (CAC) is a better metric for businesses with repeat purchases, because CAC is compared against lifetime value (LTV) rather than single-transaction revenue. A SaaS business with £40 LTV per customer should not spend £50 to acquire one. An e-commerce business with a 3x repeat purchase rate can justify a higher CAC than a one-time purchase store with the same average order value.
Cost per lead (CPL) is useful for B2B and high-ticket businesses where the sales cycle is long. But CPL alone is misleading — a channel with low CPL and poor lead quality (low close rate) can have a worse effective CAC than a channel with higher CPL and qualified leads. Always calculate effective CAC = CPL ÷ lead-to-customer conversion rate.
Worked example
See it in action
Scenario: Evaluating whether to scale a Google Ads campaign
- 1Current metrics: Monthly ad spend: £8,000. Revenue attributed: £36,000. ROAS: 4.5x. Product gross margin: 35%.
- 2Break-even ROAS: 1 ÷ 0.35 = 2.86x. Current ROAS of 4.5x is above break-even.
- 3Gross margin after ad spend: Revenue £36,000 × 35% gross margin = £12,600 gross profit. Minus ad spend £8,000 = £4,600 contribution after ads.
- 4Contribution margin on ads: £4,600 ÷ £8,000 spend = 57.5% return on ad spend in gross profit terms. This must cover overheads to be net profitable.
- 5Scale decision: If fixed overheads are £3,000/month, this campaign generates approximately £1,600 net profit. Scaling spend must maintain ROAS above 2.86x to remain margin-positive.
Result
A 4.5x ROAS at 35% gross margin generates £4,600 above ad cost — enough to cover £3,000 in overheads with £1,600 net profit. The campaign is worth scaling only if ROAS stays above 2.86x (break-even) at higher spend levels. Check efficiency before assuming it will hold.
Watch out
Common mistakes to avoid
Optimising for ROAS without checking gross margin — a high ROAS at low margin is not profitable.
Calculating CAC from ad spend only, ignoring agency fees, staff time, tools, and landing page costs.
Comparing channels by CPL without adjusting for lead quality and close rate.
Assuming ROAS is stable at higher budgets — ad fatigue and audience exhaustion often reduce ROAS as spend scales.
Not accounting for LTV in CAC decisions for repeat-purchase or subscription businesses.
Reporting blended ROAS without separating branded vs. non-branded campaigns — branded campaigns inflate the average.
Before you decide
Decision checklist
Do you know your gross margin percentage (not just revenue)?
Have you calculated your break-even ROAS (1 ÷ gross margin)?
Is your current ROAS above break-even at your actual gross margin?
Have you calculated full CAC including all channel costs, not just ad spend?
For subscription or repeat-purchase businesses: have you compared CAC against LTV?
Are you separating branded from non-branded ROAS in your reporting?
Calculated your numbers? Take the next step.
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Frequently asked questions
What is a good ROAS?
"Good" ROAS depends entirely on your gross margin. At 50% gross margin, a 2x ROAS breaks even on ad cost alone. At 25% gross margin, you need 4x ROAS just to break even. The only meaningful benchmark is: is my ROAS above my break-even ROAS? Calculate break-even ROAS = 1 ÷ gross margin. If your ROAS consistently exceeds that, the campaign is margin-positive before fixed costs.
Why is my CAC higher than my ad platform reports?
Ad platforms report cost per acquisition based on attributed conversions within their own attribution window. True CAC includes all costs to acquire a customer: total ad spend across all channels, agency or freelancer fees, internal marketing team time, tools and software, and any offline sales costs. Always calculate CAC from total spend ÷ total new customers, not from a single channel dashboard.
What is the difference between ROAS and ROI in marketing?
ROAS measures revenue generated per unit of ad spend. ROI measures net profit after all costs. A campaign with high ROAS can have low or negative ROI if gross margin is thin or overheads are high. ROAS is a useful operational metric; ROI is the business-level measure. Both are needed — but ROI is the one that determines if the business makes money.
How do I know if my cost per lead is good?
CPL is meaningful only when compared to effective CAC. Calculate effective CAC = CPL ÷ lead-to-customer conversion rate. Then compare effective CAC against LTV (or average order value for one-time purchase businesses). If LTV:CAC is above 3:1, the economics are generally healthy. If it is below 2:1, the channel is either too expensive or lead quality is too low.