---
title: "Ecommerce PPC: costs, metrics and a profit-first strategy"
description: "Ecommerce PPC judged by profit: what a click can cost, each product's break-even ROAS, and how to act on it in Google Shopping and Performance Max."
canonical: "https://www.productmetrics.io/blog/ecommerce-ppc-profitability"
pageType: article
language: en
publisher: "Product Metrics"
author: "Berend Vrakking"
datePublished: 2026-10-27
dateModified: 2026-10-27
image: "https://www.productmetrics.io/og/blog/ecommerce-ppc-profitability.png"
---

> Content index: https://www.productmetrics.io/llms.txt

# Ecommerce PPC: how to judge ads by product profit

## Key takeaways

- A product's ads break even when its ROAS equals 1 ÷ its contribution margin: 2 at a 50% margin, 5 at 20%.
- A click is worth what an order leaves after variable costs times the conversion rate: €50 at 2% allows €1.00.
- Products with different margins need different targets, because one account-wide ROAS hides the products that lose money on every sale.

Ecommerce PPC is paid advertising for online stores. [Pay-per-click](https://www.productmetrics.io/glossary/ppc) is the billing model, not a platform, and whether the ads pay depends on each product's margin more than its [ROAS](https://www.productmetrics.io/glossary/roas "Return on ad spend (ROAS) is the revenue your ads generate for every euro you spend on them.").

At the same ROAS of 4, a 20%-margin product loses €5 per €100 of sales while a 50%-margin product keeps €25. I calculated every example here from [break-even ROAS](https://www.productmetrics.io/glossary/break-even-roas "Break-even ROAS is the revenue-to-ad-spend ratio at which contribution profit exactly covers advertising costs.") = 1 ÷ [contribution margin](https://www.productmetrics.io/glossary/contribution-margin "Contribution margin is the revenue from a sale minus its variable costs, such as product cost, shipping, payment fees and returns.").

## Where does ecommerce PPC run, and is every ad charged per click?

Ecommerce PPC runs on ad platforms such as Google Ads, Amazon Ads and Meta, and not every ad is charged per click.

Google Shopping and Amazon Sponsored Products charge per click, Meta per impression unless the objective lets you pay per link click, and [Performance Max](https://www.productmetrics.io/glossary/performance-max "Performance Max is a goal-based Google Ads campaign type that uses automation to reach customers across Google advertising channels.") bills each placement in its own way.

| Platform | Ad type | Charged per |
| --- | --- | --- |
| Google Ads | Standard Shopping | Click |
| Google Ads | Performance Max | Click on Search, Shopping and Display; 1,000 impressions on YouTube in-stream |
| Amazon Ads | Sponsored Products | Click |
| Meta | Facebook and Instagram ads | Impression; link click on some objectives |

Google charges Standard Shopping per click ([About Shopping ads](https://support.google.com/google-ads/answer/2454022?hl=en)) and bills Performance Max by placement ([Understanding costs in Performance Max](https://support.google.com/google-ads/answer/15899323?hl=en)), both checked on 27 October 2026.

Amazon charges Sponsored Products per click ([Amazon Ads](https://advertising.amazon.com/solutions/products/sponsored-products)). On Meta, a new ad account has to spend USD 10 on impressions before it can pay for anything else ([About getting charged](https://www.facebook.com/business/help/146070805942156)).

Whatever the billing unit, the cost that decides profit is ad spend per order. The rest of this post uses Google Shopping and Performance Max, where the [product feed](https://www.productmetrics.io/glossary/product-feed "A product feed is a file or data source that lists your products, one per row, with attributes such as ID, title, price and availability.") drives the ads; first campaign setup is in the [Google Shopping beginner's guide](https://www.productmetrics.io/blog/google-shopping-ads-beginners-guide).

## Which numbers show whether ecommerce PPC is profitable?

Contribution after ad spend shows whether ecommerce PPC is profitable. ROAS alone can't, because it divides revenue by ad spend and ignores what the product costs.

Contribution margin is the share of revenue left after variable costs such as product cost, shipping, payment fees and returns, measured before advertising: the middle of the three [ecommerce profit margins](https://www.productmetrics.io/blog/ecommerce-profit-margins).

| Metric | Formula | What it tells you |
| --- | --- | --- |
| Cost per click (CPC) | Ad spend ÷ clicks | The price of traffic |
| Conversion rate | Orders ÷ clicks | How often a click buys |
| ROAS | Revenue ÷ ad spend | Sales per euro of ads |
| Contribution margin | (Revenue − variable costs) ÷ revenue | The share left before ads |
| Break-even ROAS | 1 ÷ contribution margin | The lowest ROAS that loses no money |
| [POAS](https://www.productmetrics.io/glossary/poas "Profit on ad spend (POAS) is contribution profit before advertising divided by ad spend.") | Contribution before ads ÷ ad spend | Profit per euro of ads |

POAS is ROAS × contribution margin, so every break-even ROAS equals a POAS of 1.0. The [POAS vs ROAS](https://www.productmetrics.io/blog/poas-vs-roas) comparison covers when to use each, and the [POAS calculator](https://www.productmetrics.io/poas-calculator) works it out for one product.

### What does one product's PPC result look like?

For example, a €100 sale with a 50% contribution margin and €20 of ad spend has a ROAS of 5, a break-even ROAS of 2 and €30 left after ads.

| Line | Amount |
| --- | --- |
| Revenue attributed to ads, excl. VAT | €100.00 |
| Cost of goods | −€38.00 |
| Shipping and packaging | −€7.00 |
| Payment fees | −€3.00 |
| Expected returns | −€2.00 |
| Contribution before ads (50% margin) | €50.00 |
| Ad spend | −€20.00 |
| ROAS (100 ÷ 20) | 5 |
| Break-even ROAS (1 ÷ 0.50) | 2 |
| POAS (50 ÷ 20) | 2.5 |
| Contribution after ads | €30.00 |

The €30 still has to cover salaries, software, rent and other fixed costs, so it isn't net profit. Revenue and margin both exclude VAT here; mix the two bases and the break-even formula gives the wrong floor.

Put your own costs into the [contribution margin calculator](https://www.productmetrics.io/contribution-margin-calculator), then take the margin to the [break-even ROAS calculator](https://www.productmetrics.io/break-even-roas-calculator) for each product's floor.

In Google Ads, the example's break-even ROAS of 2 becomes a [target ROAS](https://www.productmetrics.io/glossary/target-roas "Target ROAS is the average conversion value per unit of advertising cost that you ask Google Ads to aim for.") of 200%.

### Why does one ROAS of 4 mean different things?

A ROAS of 4 is a loss below a 25% contribution margin and a profit above it, because break-even ROAS falls as margin rises.

**Figure: Break-even ROAS by contribution margin.** Below a 25% margin, a ROAS of 4 no longer covers the ad spend.

![Bar chart of break-even ROAS by contribution margin against a ROAS of 4: 5.00 at 20%, 4.00 at 25%, 3.33 at 30%, 2.50 at 40%, 2.00 at 50% and 1.67 at 60%.](https://www.productmetrics.io/images/blog/ecommerce-ppc-profitability/break-even-by-margin.png)

| Contribution margin | Break-even ROAS |
| --- | --- |
| 20% | 5.00 |
| 25% | 4.00 |
| 30% | 3.33 |
| 40% | 2.50 |
| 50% | 2.00 |
| 60% | 1.67 |

Reference line: ROAS of 4 (4.00).

_Source: Calculated as 1 ÷ contribution margin_

Per €100 of sales, a ROAS of 4 always spends €25 on ads. The margin decides what remains.

**Figure: Contribution left per €100 of sales at a ROAS of 4.** Margin, not ROAS, sets the result: the same €25 of ad spend leaves anywhere from −€5 to €25.

![Bar chart of contribution after ad spend per €100 of sales at a ROAS of 4: minus €5 at a 20% margin, €5 at 30%, €15 at 40% and €25 at 50%. Illustrative data.](https://www.productmetrics.io/images/blog/ecommerce-ppc-profitability/roas-4-by-margin.png)

| Contribution margin before ads | Contribution after ad spend |
| --- | --- |
| 20% | -€5.00 |
| 30% | €5.00 |
| 40% | €15.00 |
| 50% | €25.00 |

_Source: Illustrative data. Contribution after ads = €100 × margin − €25 ad spend_

An account that averages a ROAS of 4 can therefore hold products losing money on every order next to the products that carry its profit. The average hides both.

### How much does ecommerce PPC cost?

Ecommerce PPC costs whatever the auction sets per click, so the number to know is the most a product can afford: its break-even CPC.

Break-even CPC is order value × contribution margin × conversion rate: for example, €1.00 for a €100 order at a 50% margin and a 2% conversion rate.

Google defines actual cost per click as "the final amount you're charged for a click", often less than your maximum bid ([Google Ads Help](https://support.google.com/google-ads/answer/6297?hl=en)).

| Conversion rate | Contribution per order | Break-even CPC |
| --- | --- | --- |
| 1% | €50 | €0.50 |
| 2% | €50 | €1.00 |
| 3% | €50 | €1.50 |

Above that price, clicks lose money on average, whatever ROAS the platform reports. That is why a cost-per-click benchmark from another store tells you little: order value, margin and conversion rate set your limit together. When you [research keywords and competitors](https://www.productmetrics.io/blog/ppc-research), compare that limit with Keyword Planner's top-of-page bid range.

Turned around, CPC ÷ conversion rate is the ad cost per order. At €0.80 per click and a 2% conversion rate, every order costs €40.00 in clicks, which a cheap product can't carry.

**Figure: Which products cover a €40.00 ad cost per order?.** At the same 50% margin and €40.00 of clicks per order, the €25 and €60 products lose money on every sale; the €150 and €300 products pay for their clicks.

![Bar chart of contribution per order at a 50% margin against a €40.00 ad cost per order: €12.50 and €30.00 fall short, €75.00 and €150.00 clear it. Illustrative data.](https://www.productmetrics.io/images/blog/ecommerce-ppc-profitability/cost-per-order-by-price.png)

| Product price | Contribution per order before ads |
| --- | --- |
| €25 | €12.50 |
| €60 | €30.00 |
| €150 | €75.00 |
| €300 | €150.00 |

Reference line: Ad cost per order (€40.00).

_Source: Illustrative data: €0.80 CPC, 2% conversion rate, 50% contribution margin, prices excl. VAT_

A better conversion rate is what moves the €60 product over the line: at 4%, its ad cost per order drops to €20.00 against €30.00 of contribution. The [ad metrics calculator](https://www.productmetrics.io/ad-metrics-calculator) gives your own CPC and conversion rate from clicks, cost and orders.

## How do you build a profit-aware ecommerce PPC strategy?

A profit-aware ecommerce PPC strategy gives each product a floor from its margin, groups the products that need the same decision and changes one group at a time.

**Run ecommerce PPC by product profit in five steps**

1. **Check product and conversion data.** Match reported purchases and values with backend orders, and make sure every advertised product is in the feed with its costs.
2. **Set each product's floor.** Work out contribution before ads and break-even ROAS per product, or per margin band when products share costs.
3. **Group products by margin and results.** Separate products only where margin or performance differs enough to need its own target or budget.
4. **Choose one action per group.** Increase priority, keep, lower priority or wait. You make the change in the ad platform.
5. **Wait out the conversion delay.** Judge a change after enough clicks and late conversions have arrived, then log what happened.

Data comes first because duplicate purchases or revenue-only conversion values make every later number wrong. The [Google Ads optimisation guide](https://www.productmetrics.io/blog/google-ads-optimize) shows how to reconcile reported purchases with backend orders, and [how to optimise PPC campaigns](https://www.productmetrics.io/blog/how-to-optimize-ppc-campaigns) takes the same order on to search terms, ads and tests.

### Which action fits each product group?

The action follows from ROAS against the product's own break-even ROAS, and from how much data the product has.

| Situation | Action |
| --- | --- |
| ROAS well above break-even, enough clicks | Increase priority |
| ROAS close to break-even | Keep, and check costs and price |
| ROAS below break-even on mature data | Lower priority or exclude |
| Few clicks or a recent change | Wait for the next review |

For products near the line, [how to improve ROAS](https://www.productmetrics.io/blog/how-to-improve-roas) works through the margin, returns and tracking fixes one product at a time.

Before you lower priority on a product, check what its visitors buy next: [Product Journeys](https://www.productmetrics.io/product-journeys) shows purchases of other products after a first click.

Doing this by hand means a margin, a floor and a data check for every product, every week. With a few hundred products in the feed, a spreadsheet stops keeping up.

> **Grow revenue with the products that perform best.** Every product segmented on profit, so you know which ones get more priority. [Analyse your products for free](https://app.productmetrics.io/) Log in with Google, no credit card.

## How does profit-first PPC work in Google Shopping and Performance Max?

In Google Shopping and Performance Max, custom labels in the product feed carry the product groups, and campaigns select products by those labels.

Google Merchant Center gives each product five custom labels, `custom_label_0` to `custom_label_4` ([custom labels](https://support.google.com/merchants/answer/6324473?hl=en)). Standard Shopping product groups and Performance Max listing groups ([listing groups](https://support.google.com/google-ads/answer/11596074?hl=en)) can include or exclude products by label.

[Product Segmentation](https://www.productmetrics.io/product-segmentation) is the grouping step: Product Metrics ML segments your products every day into six segments by ad clicks and return (ROAS, or POAS once you connect margins). It writes only the labels you approve to Merchant Center.

| Segment | Ad clicks | Return | Typical action |
| --- | --- | --- | --- |
| Stars | High | High | Increase priority |
| Question Marks | High | Medium | Test price and feed |
| Cash Cows | Low | High | Protect and grow reach |
| Dogs | High | Low | Lower priority or fix the page |
| Drainers | Low | None | Exclude or pause |
| Ghosts | No impressions | None | Reactivate or clean the feed |

You keep the campaign settings: the labels decide which products each campaign or listing group contains, and the targets stay yours. Feed and product fixes are in [optimise Google Shopping ads](https://www.productmetrics.io/blog/optimize-google-shopping-ads); exclusions and asset groups in [Performance Max for ecommerce](https://www.productmetrics.io/blog/performance-max-for-ecommerce).

### What can Auction Insights tell you about competitors?

Auction Insights shows how often your Shopping ads appeared alongside each competitor's, but not their bids, budgets, keywords or margins.

Shopping campaigns get the three metrics below, and Performance Max has its own report for its Search and Shopping ads ([About Auction Insights](https://support.google.com/google-ads/answer/2579754?hl=en)).

| Metric | What it measures |
| --- | --- |
| Impression share | Your impressions ÷ the impressions you were eligible for |
| Overlap rate | How often a competitor's ad showed when yours did |
| Outranking share | How often you ranked above a competitor, or showed when they didn't |

A rising overlap rate is a reason to compare price and margin on the products involved, not to match a rival's spend. The [Auction Insights guide](https://www.productmetrics.io/blog/google-ads-auction-insights) explains each metric and ranks the competitors in your own export.

### Where do agencies and tools fit?

Each part of ecommerce PPC has a different owner, and a profit-first workflow needs all of them to work from the same product margins.

| Who | What they do | What they don't do |
| --- | --- | --- |
| Ad platforms (Google Ads, Amazon Ads, Meta) | Run the auctions and bidding, report results | Know your product costs unless you send them |
| Agencies or in-house specialists | Plan and change campaigns | Replace product margin data |
| Profit reporting | Joins ad, order and cost data | Change which products get priority |
| Product Metrics | Segments products and writes the labels you approve; sends profit to Google Ads and Meta | Set your bids or budgets |

## Final thoughts

ROAS tells you how much an ad sold; the margin tells you whether that sale made money.

Take the ten products with the most ad spend, put each one's ROAS next to 1 ÷ its contribution margin, and start with the products below the line.

## Frequently asked questions

### Is PPC better than SEO for ecommerce?

Neither replaces the other. PPC buys visibility straight away and charges for every click; SEO costs content and time, then sends visits without a per-click charge. Use PPC where a product clears its break-even ROAS and SEO for searches you can win organically.

### Is €20 a day enough for Google Ads?

It depends on your cost per click and conversion rate. For example, €20 a day at €1.00 per click buys 600 clicks a month, which at a 2% conversion rate is about 12 orders. If that is too few to judge, spend the budget on fewer products.

### Can Google Ads bid on profit instead of revenue?

Yes, when profit is the conversion value you send. Google Ads has no POAS bid strategy, but Maximise conversion value with a target ROAS steers on that value, so a target ROAS of 150% then asks for a POAS of 1.5. Full Signal Tracking sends profit as the conversion value to Google Ads and Meta.

### Is Performance Max a type of PPC?

Yes, in everyday use. Performance Max is a Google Ads campaign type whose traffic you buy in the Google Ads auction. Google's automation sets the bids towards your conversion goal, and you steer it with targets, budgets and listing groups.

## Keep reading.

- [How to optimise PPC campaigns: a margin-first playbook](https://www.productmetrics.io/blog/how-to-optimize-ppc-campaigns)
- [How to improve ROAS: fix products, not the ratio](https://www.productmetrics.io/blog/how-to-improve-roas)
- [Ecommerce profit margins: what is good and how to calculate](https://www.productmetrics.io/blog/ecommerce-profit-margins)

---

Written by Berend Vrakking, founder of Product Metrics. Last updated 2026-10-27.

HTML version: https://www.productmetrics.io/blog/ecommerce-ppc-profitability