If you don't know your break-even ROAS, you're running ads blind. It's the one number that tells you whether a campaign is making you money or quietly bleeding you. Here's how to get it, and it takes two minutes.
The formula
Break-even ROAS = 1 divided by your gross margin.
That's it. If you keep 50 cents of profit on every rupee of revenue before ads, your gross margin is 50%, and your break-even ROAS is 1 divided by 0.50, which is 2. Your ads have to return 2x just to cover the product cost. Anything above 2 is profit. Anything below is a loss.
A 40% margin gives you 2.5x break-even. A 60% margin gives you 1.67x. Higher margin means lower break-even ROAS, which means your ads don't have to work as hard. That's the entire relationship, and it explains most arguments founders have about what a "good ROAS" is. The one with the 60% margin and the one with the 30% margin are both right from their own seat, and they're not talking about the same game.
Why the formula works
One way to see it. ROAS is revenue you get back per rupee of spend. Gross margin is the share of that revenue you get to keep. Break-even is the point where what you keep on ad-driven revenue equals what you spent.
At a 50% margin, Rs.1,000 of spend needs to produce Rs.2,000 of revenue. You keep Rs.1,000 of it. That exactly covers the spend. Dead even. Ad return a hair above 2x and you're ahead, a hair below and every order has a small loss attached. The formula is just this sentence written in math.
The part most people get wrong
Gross margin here is what you keep after the cost of the goods, not revenue minus ad spend. Subtract your COGS, your cost of delivery, shipping, packaging, payment fees, and a realistic returns reserve. What's left, as a percentage of your selling price, is your gross margin, your contribution margin per order. That's the number the formula runs on.
Say you sell at Rs.1,500. The product costs you Rs.500. Shipping, packaging and fees come to Rs.180. Returns reserve at 15% is Rs.225. That's Rs.905 in costs, leaving Rs.595. Rs.595 divided by Rs.1,500 is a gross margin of about 39.7%. Your break-even ROAS is 1 divided by 0.397, which is 2.5x.
Founders get this wrong in three ways, so let me spell each out. First: using revenue minus COGS only, and forgetting shipping and fees. Drop those Rs.180 and your margin looks like 53% instead of 40%, and your break-even looks like 1.9x when it's really 2.5x. You set a target you can't survive on. Second: pretending the returns reserve isn't real. The returns happen, the money leaves, count it. Third: comparing against average order value instead of a typical order's actual value, which drifts when you bundle or discount.
If a 2.5x break-even surprises you, most founders guess it too. They guess their break-even ROAS instead of calculating it, and they guess it far too low. They set a 2x target on a business that needs 2.5x to survive, then wonder why the bank balance never grows. Every order sits slightly underwater and no single week looks like a disaster, so the gap stays invisible until it's a year of revenue.
"Doesn't profit come from repeat purchases too?"
Yes, and this is the smartest objection to the straight break-even number, so here's how to handle it without fooling yourself. If a customer who buys once typically buys again within 90 days, the first order can carry a worse ROAS and the account still works overall.
Keep the two numbers separate. Your first-order break-even from the formula is the floor for judging acquisition spend. Then, on top of it, track LTGP against CAC, lifetime gross profit per customer against what you paid to get them. If second purchases are strong, you can hold your target a little above first-order break-even. If second purchases are weak, and for many stores they are, the first-order number is the only real floor. Never let the hope of a future purchase absorb today's loss. Measured repeat rate decides that, and most stores overestimate theirs until they count it.
Now use it
Take your calculated break-even ROAS and treat it as the floor:
- Any campaign returning below it is costing you money on every order, no matter what the dashboard says. Fix the campaign, the offer, or the margin. Don't scale it.
- Any campaign above it is contributing, and you can scale it until returns fall toward the line. That's your green light, and the drop you feel while scaling is just the return walking toward your own floor.
- Recheck the calculation whenever product cost, shipping, or returns shift. Break-even isn't a trophy you calculate once, it moves when your costs move.
This is the number that decides what a "good ROAS" is for your business. Not a rule of thumb. Not what someone said works. Your margin, your break-even, your target.
A quick worked check
Run the formula once against your own numbers right now, roughly, on paper. Selling price, minus product cost, minus shipping and packaging, minus payment and platform fees, minus a returns reserve at your real return rate. Whatever remains, divide by selling price. That percentage is your margin, 1 divided by it is your break-even, and it's worth doing before the next article starts, because most founders who compute it for the first time move their ROAS target the same day. I'd rather your target move on paper today than your bank balance move it for you in a quarter.
I'm Hirdesh Matai, founder of HDM GRO-ads, the science of e-commerce advertising.