CPA Calculator
Calculate your cost per acquisition and measure campaign efficiency.
How to Use This CPA Calculator
Formula: CPA = Total Ad Spend ÷ Number of Conversions
Enter your total advertising spend and the number of conversions (purchases, sign-ups, leads, etc.) to calculate your cost per acquisition.
Why CPA Matters
CPA is the ultimate performance metric. It tells you exactly how much you're paying to acquire each customer or conversion. Unlike CPM or CPC, which measure top-of-funnel activity, CPA measures actual business outcomes.
Your target CPA should be based on your customer lifetime value (LTV). A healthy business has an LTV:CAC ratio of at least 3:1. If your CPA is $100 and customer LTV is $300, you have a sustainable model. If CPA exceeds LTV, you're losing money on every customer.
CPA varies dramatically by industry. E-commerce might target $20-50, while B2B SaaS might accept $500+ because LTV is much higher. Always evaluate CPA relative to your specific unit economics.
Tips for Improving Your CPA
- Optimize conversion rate: Even small improvements to landing pages can dramatically lower CPA.
- Improve targeting: Focus on audiences most likely to convert, even if CPM/CPC is higher.
- Test different offers: Discount codes, free trials, or lead magnets can increase conversion rates.
- Refine your funnel: Remove friction from the conversion process—fewer fields, clearer CTAs.
- Use retargeting: Remarketing to engaged users typically has much lower CPA than cold traffic.
Want to learn more?
Read the full CPA glossary entry →