Google Shopping ROAS dropped: find out why and what to do

What this means

ROAS means return on ad spend. It's your sales value from ads divided by what the ads cost. Google's own example is $5 USD in sales ÷ $1 USD in ad spend x 100% = 500% target ROAS. In Google Ads, the sales value is called conversion value.

A drop always comes from 1 of 3 places. ROAS = (clicks x conversion rate x order value) / cost. Since cost = clicks x cost per click, the clicks cancel out:

• Cost per click (CPC) went up. You pay more for each visitor.
• Conversion rate went down. Fewer visitors out of 100 buy.
• Average order value went down. Each order is smaller.

Put last month and the month before side by side, for your Shopping and Performance Max campaigns. Performance Max is Google's all-in-one campaign type, and it shows Shopping ads too. Add the columns Cost, Clicks, Avg. CPC, Conv. rate and Value / conv. The one that moved most tells you which causes below to check first. For Performance Max, Google can also explain big moves. Hover over values in your data table that are colored in blue with a dotted line, then click View explanation. Google's list of campaign types for this covers Search, App and Performance Max, so standard Shopping campaigns don't get it.

Why it costs you money

Your break-even ROAS is the ROAS where ads just pay for themselves. It's 1 divided by your margin, the share of each sale left after product costs. With a 40% margin, that's 1 / 0.40 = 250%. Under that line, every sale from ads loses money. Find yours with the break-even ROAS calculator.

Here's a worked example for a store with a 40% margin:

• Month before: 4,000 clicks at $0.75 = $3,000 cost. 2% buy, so 80 orders at $150 = $12,000 in sales. ROAS is 12,000 / 3,000 = 400%. Profit after ads is $12,000 x 0.40 minus $3,000 = $1,800.
• Last month: the same 4,000 clicks at $0.75 = $3,000. Only 1.5% buy, so 60 orders at $120 = $7,200. ROAS is 7,200 / 3,000 = 240%. Profit after ads is $7,200 x 0.40 minus $3,000 = minus $120.

CPC didn't move. Conversion rate fell 25% (2% to 1.5%) and order value fell 20% ($150 to $120). So 400% x 0.75 x 0.80 = 240%. That's under the 250% break-even, so the account went from $1,800 profit to a small loss on the same spend. The smaller orders point at product mix and prices. The lower conversion rate points at prices, stock, the site or tracking.

If the new ROAS had been 300%, it would still be a drop. But at a 40% margin it still makes money, so you'd have time to find the cause before you touch any setting.

How to check your account in 2 minutes

Work down this list. The first ones are the quickest to rule out.

1. Sales that haven't come in yet. Buyers often buy days after the click. Google says that if you compare recent and past results, your recent performance might not look as strong, because some of the people who clicked your ad haven't converted yet. Google also notes that this lag can make your return on ad spend (ROAS) seem lower than it really is. To see your usual delay, set a date range that ends at least 30 days ago, click the segment icon, then select Conversions > Days to conversion. To match your store's sales report, add the Conv. value (by conv. time) column. It puts each sale on the day the buyer paid.
2. Tracking broke or counts twice. Compare Google Ads with your store's orders from Google for the same days. No sales recorded for days: see conversion tracking stopped. If last month's ROAS was too high because each order counted twice, the drop may be the real number showing up: see duplicate purchase conversions.
3. A new budget or Target ROAS. Target ROAS is the return you tell Google's automatic bidding (Smart Bidding) to aim for. Open Change history in the Campaigns menu. Google suggests you compare your changes with the timeline of performance data. A lower target means a lower ROAS by design. In Google's words, after a change from 500% to 400%, the strategy's performance will converge towards the new target over the course of your conversion cycle. If the budget went up, check whether ROAS fell on that same day. If the change wasn't yours, see Google changed my campaign.
4. Products got blocked or stopped selling. Open Products under the Campaigns icon and compare the 2 periods. Google says this tab helps you learn which of your products can show in ads and which can't. Sort by conversion value to find the best sellers that lost the most sales. If a best seller is disapproved in Merchant Center (the Google account that holds your product list) or out of stock, its sales stop while weaker products keep spending. That shows up as smaller orders and a lower conversion rate. See products not showing in Google Shopping.
5. Rivals got cheaper. In Merchant Center, open the Pricing tab under Analytics. It shows which of your products cost more than the benchmark, the price other sellers ask for the same item. Google says you must provide a valid GTIN for your products to get this. A GTIN is the barcode number. Also open Auction insights for the campaign. For Shopping it gives you 3 different statistics: impression share, overlap rate, and outranking share. Impression share is how often your ads showed out of the times they could have. A new seller near the top of that list, with prices under yours in the Pricing tab, can explain a lower conversion rate.
6. The season. Compare the same weeks last year. If your ROAS fell by a similar amount then, this drop is probably your normal calendar. Google says Smart Bidding already manages seasonal events.
7. Brand searches moved. People who type your store name usually buy more often than other shoppers. If you added a brand campaign or brand exclusions (a list that stops a campaign showing on searches for your store name), those sales leave Shopping, and its ROAS falls while the account total holds. Check your total sales from ads, then see Performance Max brand searches or brand searches in a non-brand campaign.
8. Feed or title edits. Google says your title will be used to match your product to a customer's search. A feed app (the tool that sends your product list to Google) or a bulk edit that rewrote titles can send your ads to weaker searches. Ask whoever runs your feed what changed, and when. Also check whether AI Max for Shopping was turned on. It's a beta that lets Google optimize your ad copy (for example, product titles). If it went on the day the drop began, that's your first suspect.

When it is not a problem

• The last 7 to 14 days look bad, and older weeks look fine. That's usually late sales. Wait until the window is older than your usual delay, then compare again.
• You lowered Target ROAS on purpose to grow. A lower ROAS with more total profit is the trade you asked for. Judge it by profit in dollars.
• You get fewer than 10 or so orders a month. With few sales, 1 big order swings ROAS a lot. Look at a longer date range.
• The new ROAS is still above break-even. You still make money on each sale, so find the cause calmly and change 1 thing at a time.

How PerfoAds flags it

PerfoAds compares your last 30 days with the 30 days before. It flags the account when ROAS fell 20% or more. It needs at least 10 days of data and 10 conversions in each 30-day period, or it gives no verdict. The card always states the latest week next to the drop, and it says the recent 30 days may still get late sales.

It also says which campaign moved the account. For each campaign it works out the sales the same spend would have brought at its earlier ROAS. In the example above, (400% minus 240%) x $3,000 = $4,800 of missing sales value. The campaign with the biggest gap is named first. Campaigns that improved stay in the table too, so you can see if the drop belongs to 1 campaign or to all of them.

The same check runs per campaign, for any campaign type with 14 or more active days. A campaign with a tracking break is skipped there, because the tracking check handles it. For the whole account, PerfoAds also compares the move with the same weeks a year ago. Last year's move counts as the reason when it went the same way and was at least half as big.

It lists dated budget, bidding target and on/off changes from the last 30 days. Google only lets tools read Change Event data from the past 30 days, so an older change can't be ruled out this way. Use Change history in Google Ads for those.

Once monitoring is on, PerfoAds checks your Search and Shopping campaigns every day. By default, it flags yesterday's ROAS when it's more than 30% under the 7-day average, on a day with more than 50 in spend (in your account's currency). Each flag feeds that day's alerts, and a day shows at most 5. Performance Max isn't part of this daily check, so a drop there shows up in the 30-day check above. You can make the check more or less sensitive, or turn it off.

How to fix it

1. Wait out the delay first. Compare only windows older than your usual days to conversion. This step alone ends many false alarms.
2. Fix tracking before anything else. Google says Google Ads predicts future conversions and associated values using your reported conversion values. If those values are wrong, every other fix is built on bad numbers.
3. Undo the change that caused it. If Change history shows a new target or budget on the day the drop began, put it back. Google warns to avoid making multiple target changes within a single conversion cycle unless there is a clear business need. A conversion cycle is the usual time from click to sale. Make 1 change, then wait.
4. Get blocked best sellers back. Fix the Merchant Center issue or restock. Until then, keep spend off products that can't sell.
5. Answer price gaps product by product. For items where you're well above the benchmark, choose: match the price, run a promotion, or spend less on that item. Google notes that only the latest prices are available at a given time, so screenshot the tab now if you want a record to compare later.
6. Plan for the season. For a short sale you know is coming, Google offers seasonality adjustments. Google's advice is to use seasonality adjustments only if you expect major changes to conversion rates.
7. Reset Target ROAS only last. If nothing above explains it and the new ROAS stays under break-even, raise your target toward break-even plus the profit you want. Google warns that setting a target that's too high may limit the amount of traffic your ads may get, so expect fewer clicks.

A 2026 note: Google says that starting August 17, 2026, it's updating bidding for campaigns that are limited by budget, and these changes may cause temporary performance and traffic fluctuations if you use Target CPA (a target cost per sale) or Target ROAS. If your drop began then and the campaign is short on budget, see limited by budget.