If you've googled this question, you've probably seen answers ranging from "$5 a day is fine" to "10% of revenue or don't bother." Both can be right, for different businesses. Here's how to actually find your number.

Start with the math, not the budget

Work backwards from a customer. Say you're a med spa and a new client is worth $400 on their first visit. If your booking rate from leads is 1 in 4, a lead is worth about $100 to you. That means you can pay $30-50 per lead and still be comfortably profitable. If you don't know these two numbers , customer value and lead-to-customer rate , figure them out before spending a dollar. Everything else depends on them.

Set a budget that can produce useful data

The appropriate test budget depends on expected cost per lead, conversion volume, market competition, campaign structure, and the decisions the test needs to inform. If the available budget cannot generate enough data for a meaningful evaluation, strengthen the offer, landing page, tracking, Google Business Profile, or review process before forcing a paid campaign.

Use a defined test window

A useful test window depends on budget, conversion volume, sales cycle, creative, and tracking quality. Set decision points before launch, then avoid calling a campaign successful or unsuccessful from a handful of early results.

When to scale (and when to stop)

Scale only after the account has enough reliable conversion and lead-quality data to support the decision, and confirm that follow-up can handle more volume. Change budgets deliberately and monitor the effect. If leads arrive but do not book, review targeting, offer, landing-page friction, qualification, and follow-up before assuming the ad channel is the only problem.

The part nobody talks about

Ad performance depends on more than the campaign itself. Prompt, consistent follow-up gives the business a better chance to turn interest into a conversation. Before raising the budget, check how leads are routed, how quickly the team responds, and what happens when an inquiry arrives outside normal hours.

Want a second opinion on your numbers? We can review the account during a free growth call and identify the most useful next checks.