i keep running into ecommerce operators who celebrate a 300% ROAS like it's a trophy, but their cash position tells a completely different story. the culprit is almost always gross margin. Plug in different margins and the same ROAS flips from profit to loss like a light switch.
Quick numbers that stick in my head: at a 30% margin, every pound of ad spend generates 90p of gross profit - you're losing 10p. bump that margin to 50% and you're making 50p profit per quid. at 70%? A healthy £1.10 surplus.
The maths is straightforward: breakeven ROAS equals 100 divided by your gross margin percentage. so a consumer electronics shop scraping by on 20% margin needs a ROAS of 500% just to break even. Meanwhile a cosmetics brand sitting on 70% can break even at 143% ROAS.
where this gets really interesting is the spectrum across verticals. Cosmetics and supplements float in that lush 60-75% margin zone - a 300% ROAS there is pure luxury. apparel sits around 50-60%, decent but not dazzling. general goods hover 35-50%, food tight at 25-35%, and consumer electronics scraping the bottom at 15-25%. that same 300% headline that gets a standing ovation in an electronics store is a guaranteed bloodbath, while the cosmetics shop with the identical number is laughing all the way to the bank.
i know someone's about to say 'everyone with half a brain knows this' - and yet I've lost count of founders who set a ROAS target without ever factoring in their actual margin. They anchor on a vanity metric and wonder why profits are vanishing.
what's your category margin? And do you actually calculate the breakeven ROAS from that number before setting ad spend targets, or are you still chasing that pretty three-digit figure?
