Work back from your revenue goal: orders needed x share that must come from ads x your target cost per purchase. As a floor, give each ad set enough budget to reach around 50 purchases a week, or at least several purchases a day. For most small brands that means $50 to $150 a day in one or two campaigns, rather than small amounts spread across many.
Step 1: know your target CPA
Your target cost per acquisition is the most you can pay for an order and still make the profit you want. Use the break-even calculator to find it.
Step 2: work back from your goal
Say you want $30,000 a month at a $65 average order. That's about 460 orders. If 30% come from returning customers and another 25% of new customers arrive through organic and email, about 240 orders need to come from ads. At a $40 CPA, that's roughly $9,600 a month, or $320 a day.
Why spreading budget thin fails
Meta's delivery system learns from conversions. An ad set that gets two purchases a week never gathers enough signal to find the right buyers. Five ad sets at $20 a day usually perform worse than one at $100 a day.
What if you can't afford the "right" budget?
- Consolidate to one sales campaign and one testing campaign.
- Optimise for add to cart temporarily if purchases are too few, then switch back.
- Raise order value with bundles, which raises the CPA you can afford.
How fast should you increase budget?
Around 20% every three days while cost per purchase holds is a reliable pace. Bigger jumps can push an ad set back into learning.
Budget and scaling planner
Frequently asked questions
What is the minimum budget for Meta ads?
There's no official minimum that guarantees results, but a sales campaign needs enough budget to generate regular purchases. Below about $30 to $50 a day, most stores struggle to exit learning.
Should I split budget between many audiences?
Usually not. On small budgets, one broad audience with strong creative tends to beat many narrow audiences, because Meta learns faster with more data per ad set.
How much should I spend on testing new ads?
Around 20 to 25% of total budget is a good rule of thumb, with the rest behind proven ads.
Written by Shimeez Bok, founder of Growth Alchemy, an ecommerce growth studio in Auckland, New Zealand.
