Understanding ROAS and Key Ad Metrics

Quick answer

ROAS (return on ad spend) is revenue from your ads divided by ad spend. It only tells you whether ads pay off when you compare it with your break-even ROAS, which is 1 divided by your gross margin. MER is the store-wide check: ad spend divided by total store sales, shown as a percentage. Lower MER is better. Watch both.

For a quick read on your own account, ask your AI Strategist on the Agency AI home page: "What were my ROAS and MER for the last 30 days, and how do they compare with my break-even?"

ROAS

ROAS = revenue from ads ÷ ad spend. Spend 100 and the platforms attribute 400 in sales to your ads: ROAS 4.0, sometimes written 400%.

A good ROAS depends on your margin. A store with a 60% margin profits at a ROAS that would run at a loss for a store with a 25% margin. That's what break-even ROAS is for.

Break-even ROAS

Break-even ROAS = 1 ÷ gross margin. With a 40% margin: 1 ÷ 0.40 = 2.5. Below 2.5, ads run at a loss on the first order. Above it, they're profitable.

  • 25% margin: break-even ROAS 4.0
  • 33% margin: 3.0
  • 40% margin: 2.5
  • 50% margin: 2.0
  • 60% margin: 1.7

Use your margin after product cost, shipping, payment fees and returns. Your break-even ROAS is on Brand Info, and recommendations use it. See Where your break-even ROAS and target ROAS come from.

MER

MER = ad spend ÷ total store sales, shown as a percentage. Lower is better. 1,000 in ad spend and 5,000 in total sales is an MER of 20%.

MER counts every sale in your store, organic and repeat orders included. Meta and Google can both claim the same order in their ROAS, but MER counts it once. Use it as the reality check on platform ROAS.

Break-even MER = your gross margin as a percentage. With a 40% margin, break-even MER is 40%. Above that, ad spend is eating more than your gross profit.

MER isn't the same as 1 ÷ ROAS. ROAS uses the revenue the platforms attribute to your ads. MER uses all your store sales.

NC-ROAS

NC-ROAS = revenue from first-time customers ÷ ad spend. It shows how well your ads win new buyers, without repeat customers lifting the number.

CPA (Cost Per Acquisition)

CPA = ad spend ÷ purchases. Spend 200 and get 10 purchases: CPA 20.

Compare it with the gross profit on an order. With an 80 average order and a 40% margin, each order earns 32. A CPA under 32 is profitable on the first purchase, and more so if the customer comes back.

CTR (Click-Through Rate)

CTR = clicks ÷ impressions × 100. 150 clicks from 10,000 impressions is a CTR of 1.5%.

CTR shows how well the ad grabs attention. It doesn't tell you whether those clicks buy, which is why ROAS and CPA matter more.

CPM (Cost Per 1,000 Impressions)

CPM = ad spend ÷ impressions × 1,000. Spend 50 for 10,000 impressions: CPM 5.

CPM rises with competition for your audience and with the season. It usually peaks in Q4. You can't set it directly, but ads people engage with tend to get cheaper delivery over time.

CPC (Cost Per Click)

CPC = ad spend ÷ clicks. Spend 100 for 200 clicks: CPC 0.50.

Conversion rate

Conversion rate = purchases ÷ visitors × 100. 15 purchases from 500 visitors is 3%. This is a store metric, not an ad metric. Find it in Shopify Analytics. If it's low, look at your product pages, checkout, pricing and trust signals before you blame the ads.

How they fit together

CPM is the cost to reach people. CTR is how many of them click. CPC is the cost of each click. Conversion rate is how many clicks buy. CPA is the cost of each sale. ROAS and MER tell you whether the whole thing is profitable.

Work down that chain to find the weak spot. High CPM with normal CTR points to a crowded audience. Good CTR with a low conversion rate points to the landing page. Plenty of sales with ROAS under break-even points to price or margin.

General reference ranges

These are typical e-commerce ranges for orientation only. They are not your targets. Your break-even ROAS and break-even MER are the lines that matter for your store.

  • CTR on Meta: around 1% to 3%.
  • Conversion rate from paid traffic: around 1% to 3%.
  • ROAS: many stores need 3 or more to profit after all costs. Check it against your own break-even.

Where to see these in Agency AI

  • Stats on the Agency AI home page: Total Sales, Total Orders, Average Order Value, Ad Spend, ROAS, MER and NC-ROAS.
  • Manage ads: cost, revenue and ROAS for every campaign, ad set and ad, CPM on most tabs, Cost Per Result on Meta campaigns, and CPC and CPA on Google campaigns.
  • Ad Performance Recommendations on the Agency AI home page: Spend, ROAS, CPA, CTR and Conv for each campaign or ad it flags.
  • AI Dashboard: charts on Performance and CSV exports on Reports.
  • AI Strategist: ask it directly, for example "Which campaign has the lowest CPA this month?"

More: Glossary of ad metrics, How to track ad performance and Why your numbers don't match.

Questions? hello@agencyai.app.

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