The short version
Your Meta budget is the number of sales you want times what a sale costs you, plus a fixed slice for testing new creative.
Monthly budget = (sales goal × CPA) + (creatives tested × test spend per creative)
Want 100 sales a month at a $40 cost per sale? That's $4,000. Testing 12 new creatives at 2x CPA each adds $960. Total: $4,960 a month, or about $163 a day.
Where the CPA comes from
Use your real cost per sale from the last 30 to 90 days if you have it. If you don't, use your break-even CPA as a ceiling: the most you can pay for a sale before it loses money. The break-even calculator gives you that number from your order value and costs.
Be honest here. A budget built on a hoped-for CPA runs out halfway through the month.
Why testing gets its own line
New creative is what keeps an account alive. Ads wear out, and the next winner has to be found before the current one fades. I explain why in ad fatigue and the creative volume problem.
The test spend comes from my kill rules: don't judge an ad before it has spent about 1 to 1.5x your target CPA, and kill it once it has spent 2 to 3x with nothing to show. Budgeting 2x CPA per new creative covers a fair test.
Testing money isn't wasted money. It's how you buy next month's winners.
The learning phase floor
Meta's delivery system needs data to settle. Its guidance in About the learning phase is roughly 50 optimization events per ad set within 7 days.
Weekly spend per ad set to exit learning ≈ 50 × CPA
At a $40 CPA that's about $2,000 a week for each ad set. If your budget can't feed that, run fewer ad sets. Splitting a small budget across many ad sets keeps all of them stuck in learning.
Daily or lifetime budget?
For always-on campaigns I use daily budgets. They're easier to read and to scale. Lifetime budgets make sense for fixed-date pushes like a launch or a sale.
Pool rule 003Be prolific. Volume finds winners.
Quick answers
How much should I spend on Facebook ads per day? Enough to buy the sales you need at your real cost per sale. Your monthly goal times CPA, divided by about 30.4.
How much should a small business spend on Facebook ads? Start from what a customer is worth and what one costs to get. A budget that can't produce a few conversions a week won't teach you much.
How long should I test a Facebook ad before turning it off? Until it has spent about 1 to 1.5x your target CPA. Kill it at 2 to 3x with nothing to show.
How much do Facebook ads cost? It depends on your industry, audience and creative. I break down real benchmarks in how much Facebook ads cost.