Cost/Conv.
What one Google sale costs you in ad money — and whether your margin can carry it.
What it means
Cost/Conv. is your Google Ads spend divided by the conversions Google recorded in the same period: €12,000 across 240 conversions is €50 a sale. It's a euro cost per tracked conversion, so it uses Google's count rather than your Shopify order count. Lower is better, down to the point where cutting it also cuts the volume you wanted.
Show the math
Formula and a worked example
Ad Spend is the Cost figure for the same period and rows you're looking at. Conversions is Google's tracked count, which arrives as a decimal and fills in for days after the click, so a fresh week always reads dearer than it will finish.
Worked example. €12,000 ÷ 240 conversions = €50 a sale. If an average order leaves you €70 after product, shipping and fees, you keep €20 and can buy more. At 200 conversions each sale costs €60 — still profitable, with half the room.
At 150 conversions it's €80 a sale and every order loses €10. The spend never changed; volume alone did it.
It answers the question
Can you afford another sale at this price? Hold it against what an order leaves after costs — if the answer is yes, your constraint is budget, not efficiency.
Why it matters
This is the number that decides whether you scale or stop. Most of the other figures here describe activity; this one prices the outcome, in the same currency as the margin an order leaves you.
It also rises for two very different reasons that need opposite fixes. A dearer click is an auction problem, handled with bids, negatives and relevance; a falling conversion rate is a shop problem, handled on the page, and bids alone won't fix it.
What good looks like
There's no published standard, and there couldn't be — €50 a sale is a bargain on a €300 basket and ruinous on a €35 one. Judge it first against your own contribution per order: the ceiling is what an order leaves after product, shipping, fees and returns. Then judge the trend against your own category, since a considered purchase always costs more to buy than an impulse one.
How to improve it
| Lever | What you do | Expect | How long | Watch out for |
|---|---|---|---|---|
| Fast Cut the terms that spend and never convert | Add negatives for search terms with real spend and zero conversions over 60 days | Cost/Conv. down 5–10% | 1 week | You remove the discovery queries with them. Some of those were how new customers first arrived, and Search IS on the broader theme falls too. |
| Fast Bid down where the sale costs too much | Lower targets on campaigns sitting well above your contribution per order | Cost/Conv. down, conversions down with it | 1–2 weeks | Volume goes first and efficiency follows, so total profit can fall while this number improves. Positions you give up cost more to win back. |
| Slow Raise the conversion rate, not the bid | Fix the landing page — real delivery times, visible price, fewer checkout steps | Cost/Conv. down 10–25% at an unchanged Avg. CPC | 3–6 weeks | Development time, and each change needs long enough to be judged. Move pages and bids in the same week and you learn nothing from either. |
| Slow Sell a bigger basket | Bundles, volume pricing and cross-sells so one conversion is worth more | Cost/Conv. flat, but the price you can afford goes up | 1 quarter | This raises the ceiling rather than lowering the cost, and bundle discounts eat Gross Margin — the room only grows if the discount is smaller than the basket gain. |
Every lever costs something somewhere. The last column is the one to read twice.
Read it with
The price of a sale means nothing until you know how many sales it bought.
The account is compounding
More sales, each one cheaper. This is the only quadrant where you can add money without arguing about it.
Growth at a rising price
Expected when you scale into colder auctions. Set the ceiling you won't cross before the next budget rise, not after it.
Efficient and small
You're buying cheaply and not buying much. Efficiency without volume is a throttled account, not a healthy one.
Fewer sales, dearer sales
Both halves moved the wrong way at once, which points at something that broke rather than drifted. Check tracking and stock before bids.
One is what a sale costs to buy, the other is what a sale leaves behind. Contribution Margin is a percentage, so turn it into euros against your average order first: €50 a sale against €70 of contribution per order is a business; against €45 it's a subsidy, however good the campaign looks.
These two separate an auction problem from a shop problem. Cost/Conv. up with Avg. CPC up means you're paying more for the same visits — bids, competition, relevance. Cost/Conv. up with Avg. CPC flat means fewer of those people are buying, which no bid change will fix.
Common misreads
It's usually the brand campaign, buying people who were already on their way. It looks cheap because the demand was free, and there's rarely more of it available to buy.
Revenue isn't margin. The comparison is against what an order leaves after product cost, shipping, fees and returns, which is normally well under half the basket.
Spend is recorded immediately and conversions backfill for days, so the most recent stretch always reads expensive. Wait for the window to settle before you cut a bid over it.
Also called
Cost per conversion · CPA · cost per acquisition
See yoursYour Cost/Conv. by campaign and by product for the last 30 days.
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