Break-even ROAS is the return on ad spend at which your ads pay for themselves and leave no profit or loss. You calculate it by dividing your selling price by what you keep from each sale after product, shipping and fees, which is the same as 1 ÷ your margin. With a 45% margin, your break-even ROAS is 2.22.
That one number answers the budget question the right way round. Instead of asking "how much should I spend on Facebook ads?", you ask "how much can I pay for each sale and still make money?" Once you know that, the budget is simple math. Below is the full method with a worked example, plus a calculator for your own numbers.
What is ROAS?
ROAS (return on ad spend) is the revenue your ads bring in divided by what you spent on them.
ROAS = ad revenue ÷ ad spend
Spend $440, bring in $1,200 in sales, and your ROAS is 2.73. That sounds healthy, but ROAS measures revenue, not profit. Whether 2.73 makes you money depends entirely on your margin.
How do you calculate break-even ROAS?
Break-even ROAS = selling price ÷ profit per sale before ads
Profit per sale before ads is your price minus every cost of fulfilling that order: the product, packaging, any shipping you pay for and payment processing fees. Leave out fixed costs like rent, software and your own salary; those come out of whatever is left later.
Worked example: a candle shop
Say you sell a candle gift set for $60. Wax, jars, fragrance, the box, shipping and card fees add up to $33 per order.
- Profit per sale before ads: $60 − $33 = $27, a 45% margin.
- Break-even ROAS: $60 ÷ $27 = 2.22.
At a ROAS of 2.22 your ads exactly pay for themselves. At 2.73 you make a profit. At 1.9 you lose money on every ad-driven sale, even though Ads Manager shows purchases coming in.
Break-even ROAS by margin
- 70% margin: 1.43
- 50% margin: 2.00
- 40% margin: 2.50
- 30% margin: 3.33
- 20% margin: 5.00
The lower your margin, the harder paid ads get. At 20%, every ad dollar has to bring back five in sales just to stay even.
What is the most you can pay per sale?
Your maximum profitable CPA (cost per acquisition, shown in Ads Manager as "cost per result" when you optimize for purchases) is simply your profit per sale before ads. For the candle shop, that's $27. Pay $22 to get a sale and you keep $5; pay $30 and you lose $3.
CPA = ad spend ÷ number of sales
Break-even ROAS and max CPA are two views of the same limit: a $27 CPA on a $60 product gives a ROAS of exactly 2.22.
How much should you spend on Facebook ads each month?
Monthly budget = sales you want from ads × expected CPA
If the candle shop wants 20 sales a month from ads and expects a $22 CPA, the budget is $440. Here's what that leaves:
- Revenue: 20 × $60 = $1,200, a ROAS of 2.73.
- Profit before ads: 20 × $27 = $540.
- Profit after ads: $540 − $440 = $100, before fixed costs.
Notice how thin that is. Each sale leaves $5 after ads, so earning another $500 a month would take 100 more sales and $2,200 more in spend. Before scaling, it usually pays off more to lower the CPA, with better creative and a faster product page, or to raise the average order with bundles.
How do you set a target ROAS?
Break-even is the floor, not the goal. Your target ROAS is the one that leaves the profit you actually want from each ad-driven sale.
Target ROAS = selling price ÷ (profit per sale before ads − profit you want per sale)
If the candle shop wants every sale from ads to leave $10 after paying for the ad, it can spend at most $27 − $10 = $17 per sale. Its target ROAS is $60 ÷ $17 = 3.53. Anything between 2.22 and 3.53 still makes money, just less than planned.
The same logic works for fixed costs. If the shop has $300 a month in fixed costs it wants ads to cover, and each sale leaves $5 after ads, it needs 60 ad-driven sales a month before the ads have paid their share. That's a useful reality check before you promise yourself that ads will fund the business.
Keep in mind that ROAS in Ads Manager depends on the attribution window Meta uses, so the number you see may include some sales that weren't caused by the ad. Leave yourself some margin between your break-even and your target instead of running right at the edge.
Break-even ROAS calculator
Enter your own numbers. If you've never run ads, start with a pessimistic CPA and see where the campaign stops making money.
What if you only know your cost per click?
Early on you may only have a cost per click from a traffic campaign. To turn clicks into sales you need your conversion rate: out of every 100 visitors, how many buy.
CPA = cost per click ÷ conversion rate
At $0.55 per click and a 2.5% conversion rate, CPA is $0.55 ÷ 0.025 = $22. With the same clicks at a 1% conversion rate, CPA jumps to $55, about double the candle shop's limit. A slow or confusing product page doesn't change what you pay per click; it changes how many clicks you need to make a sale. That's why the most common small business website mistakes show up directly in your ad costs.
How much should you spend on your first test?
Your first campaign is for learning your real CPA, not for profit. Pick an amount you can lose without it hurting, and let it run for at least two weeks without daily tweaks, because major edits restart the delivery system's learning.
Meta's help article on the learning phase explains that each ad set needs to collect results before delivery stabilizes. On a small budget, that means:
- One campaign and one ad set with two or three different ads. Splitting $200 across five ad sets leaves each one short of data.
- Optimizing for the result closest to a sale that you can actually track. If you get few website purchases or haven't set up the pixel, optimize for messages and track how many turn into orders.
- Using a daily budget so spend is spread out. $440 a month is roughly $15 a day.
When the test ends, plug your real CPA into the calculator and decide with numbers whether to scale, hold or pause.
Common ROAS mistakes
- Comparing ROAS to industry benchmarks instead of your break-even. A ROAS of 3 is great at a 50% margin and a loss at 25%.
- Leaving shipping and fees out of your costs. Your break-even looks lower than it really is.
- Trusting attribution blindly. Ads Manager may claim sales that would have happened anyway. Compare total monthly sales with and without ads.
- Scaling too fast. Raise budgets gradually and check that your CPA holds.
- Running ads on a price with no room. If your break-even ROAS is above 4 or 5, fix pricing first: see how to calculate a selling price.
Frequently asked questions
Any ROAS above your break-even ROAS. With a 50% margin that's anything over 2; with a 25% margin you need more than 4. Industry averages don't help much because margins vary so widely between businesses.
No. Break-even ROAS is the floor where ads pay for themselves. Target ROAS is higher, because it also has to cover your fixed costs and leave the profit you want.
Divide 1 by your margin as a decimal. A 40% margin gives 1 ÷ 0.40 = 2.5. Make sure that margin includes shipping, packaging and payment fees, not just the product cost.
ROAS compares revenue to ad spend. ROI compares profit to what you invested. A campaign can show a ROAS of 2 and still lose money if your margin is under 50%.
Wrapping up
Know your break-even ROAS before you set a budget: it tells you the most you can pay for each sale. Test small, measure your real CPA, and only scale what stays under that limit.
Want a second pair of eyes on your numbers? Our free audit looks at your website, Instagram and ads and shows you where the budget is leaking. If you'd rather hand it off, we also run digital management and ad campaigns.