Most people set their Meta Ads budget by guessing. Here's the actual formula — four numbers, one calculation — plus a worked example.
Most people set their Meta Ads budget by guessing — pick a round number that feels affordable, launch the campaign, and hope for the best. The problem is that a budget disconnected from your actual numbers either starves your campaign before it can learn, or burns cash on a funnel that was never going to break even in the first place.
The good news: figuring out the right number takes four inputs and one simple formula. Here's how to do it properly, plus a free calculator at the bottom so you don't have to do the math by hand.
A $20/day budget might be way too much for a $15 product with a 1% conversion rate — you'd be burning money on clicks that were never going to convert profitably. Or it might be way too little for a $400 product where you can easily afford to pay $15 per click and still turn a healthy profit.
Budget only makes sense in the context of your funnel. Once you know how your funnel performs, the budget calculates itself.
How much revenue do you want Meta Ads to generate this month? This is a target you set based on your business goals — not something Meta tells you.
The average amount a customer spends per purchase. Formula: total revenue ÷ number of orders. If you've made $8,000 from 100 orders, your AOV is $80. Check this in your store dashboard, or use your product's price if you haven't sold anything yet.
The percentage of people who click your ad and then actually complete a purchase. Formula: (purchases ÷ clicks) × 100. If you've run ads before, this is in Ads Manager. If you're starting from zero, 1–3% is a reasonable estimate for e-commerce.
What Meta charges you, on average, each time someone clicks your ad. Check "CPC (Cost per Link Click)" in Ads Manager if you've advertised before. If you're new, expect somewhere between $0.50–$3, depending on your country and niche.
Once you have those four numbers, the math is straightforward:
Conversions needed = Revenue goal ÷ AOV Clicks needed = Conversions needed ÷ Conversion rate Monthly budget = Clicks needed × CPC
Say you want to hit $10,000 in revenue this month. Your average order is $80, your landing page converts at 2%, and your CPC runs about $1.20.
Conversions needed: $10,000 ÷ $80 = 125 sales
Clicks needed: 125 ÷ 2% = 6,250 clicks
Monthly budget: 6,250 × $1.20 = $7,500
That's roughly $250/day to hit your goal — and it also tells you your implied cost per sale (CPA) is $60, well under your $80 order value, meaning the funnel is profitable before you even launch.
Sometimes this exercise reveals a problem before you've spent a dollar. If your implied CPA comes out higher than your AOV, you're set up to lose money on every first-time sale — no amount of "optimizing" the campaign fixes a funnel that's mathematically upside down. In that case, you'd need a higher AOV (bundle, upsell), a better conversion rate (stronger landing page), or a strategy that accounts for repeat purchases and lifetime value rather than breaking even on order one.
This is exactly the kind of thing worth checking before you set a budget, not after your ad account tells you the hard way.
Free calculators for Meta, Google, TikTok, and a ROAS-based model — no signup, no email required.
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