Facebook Ads Budget Calculator

How Much Should You Spend on Facebook Ads?

The right Facebook Ads budget isn't a fixed number — it's a function of your target CPA and the number of ad sets you're testing. Meta's algorithm needs approximately 50 conversions per ad set per week to optimise effectively. Below that threshold, delivery is inefficient and results are unreliable.

Why Underfunding Campaigns Is So Costly

Spending $200/month at a $20 CPA gives you 10 conversions. The algorithm needs 200 per month (50 × 4 weeks) to stabilise. At 10, you're getting noise, not signal — some weeks showing excellent ROAS by chance, others terrible, with no reliable way to distinguish what works. The result is months of inconclusive data and decisions made on random variation rather than genuine performance.

Testing Budget vs Scaling Budget

These require different mindsets. During testing, you're buying data — deliberately running at unknown profitability to find which creative, audience, and offer combination converts. Expect some losses. Once you find a winner, the scaling budget is about growing profitable spend while keeping CPA stable. Meta's 20% rule — increase daily budget by no more than 20% every 3–4 days — keeps the algorithm from re-learning at each new spend level.

How Customer Retention Raises Your Viable CPA

If your customers make repeat purchases, their lifetime value may justify a higher CPA than first-order margin alone suggests. A customer worth $200 over 12 months can support a $40 acquisition cost even if the first order only generates $20 in margin. This calculator shows the max profitable CPA based on first-order margin — if your retention is strong, your true ceiling is higher.

Always pair your CPA target with your Meta Ads break-even ROAS to make sure the economics hold at your margin.

Frequently Asked Questions