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How to calculate ROI and ROAS of advertising: formulas and examples

What is ROI, ROAS, and CPA in marketing. Formulas with examples. How to understand that advertising is paying off and when to turn it off.

Published February 23, 2026·Time to read: 8 min

ROI vs ROAS: what''s the difference?

ROI (Return on Investment) - return on investment as a whole.

ROAS (Return on Ad Spend) - return specifically on advertising costs.

ROI = (Profit - Investment) / Investment × 100% 
ROAS = Revenue / Advertising Expenses 

Practical examples

Example 1: e-commerce

- Spent on advertising: 100,000 ₽

- Advertising revenue: 400,000 ₽

- Cost of goods: 200,000 ₽

- ROAS = 4 (or 400%) - good

- ROI = (400k - 100k - 200k) / 100k × 100% = 100% - excellent

Example 2: SaaS subscription

- Advertising expenses: 50,000 ₽/month

- New subscriptions: 50 × 2000 ₽/month = 100,000 ₽/month

- ROAS = 2 — pays off if LTV '>' CAC

Important metrics

MetricFormulaWhat does
---------
CPASpend/ConversionsCost of attraction
LTVCheck × Frequency × MonthsCustomer Lifetime Value
CACExpenses / ClientsCost of customer acquisition
Break-even ROAS1/MarginMinimum ROAS for exit to 0

When to turn off advertising?

- ROAS '<' 1 → you spend more than you earn

- CPA '>' LTV → attracting a customer costs more than their value

- ROI '<' 0 → loss

Calculate the ROI and ROAS of your advertising campaign with our free calculator.

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