---
title: "POAS Bidding in Google Ads: The Practical Guide"
description: How to switch from ROAS to POAS bidding in Google Ads. Covers tools, manual setup, overhead calculations, and a safe 3-phase switch protocol. British PPC consultant.
url: "https://steviemorris.com/ecommerce/switching-to-poas-bidding-in-google-ads-the-practical-guide-stop-chasing-revenue/"
canonical: "https://steviemorris.com/ecommerce/switching-to-poas-bidding-in-google-ads-the-practical-guide-stop-chasing-revenue/"
type: article
silo: na
category: ecommerce
location: 
primary_keyword: POAS bidding Google Ads
keywords:
  - POAS Google Ads
  - profit on ad spend
  - switch from ROAS to POAS
  - Google Ads profit bidding
blueprint: 0
audience: UK business owners
date_published: 2026-06-30
date_modified: 2026-06-30
author: Stevie Morris
schema_types:
  - Article
  - FAQPage
  - BreadcrumbList
record_id: article__switching-to-poas-bidding-in-google-ads-the-practical-guide-stop-chasing-revenue
word_count: 1593
---

# Switching to POAS Bidding in Google Ads: The Practical Guide (Stop Chasing Revenue)

POAS (Profit on Ad Spend) replaces revenue with actual profit as your Google Ads conversion value. Google then optimises for money you keep, not money you turn over. Switch safely in three phases over four weeks using existing bidding infrastructure.

## Why Revenue Is Lying to You

There's a version of Google Ads success that looks brilliant on paper and ruins your business in practice. Strong revenue numbers, healthy-looking ROAS, [a dashboard full of green](/data/how-to-read-a-google-ads-report-2/) — and a bank account that tells a completely different story.

The problem is structural. **ROAS treats all revenue as equal.** It does not know that your £100 sale cost you £90 to fulfil, or that your £50 sale cost you £10. It sees two sales and calls both wins.

Here's the same scenario made concrete:

**Product A:** Sells for £100, costs £90 to fulfil. Margin: £10. You spend £20 on ads to generate that sale. ROAS = 500%. Actual result: *you lost £10.*

**Product B:** Sells for £50, costs £10 to fulfil. Margin: £40. Same £20 ad spend. ROAS = 250%. Actual result: *you made £20 profit.*

Product B's ROAS looks worse. Product B is the one keeping the lights on. ROAS cannot tell the difference — and that is why so many [ecommerce businesses](/ecommerce-ppc-consultant/) are scaling the wrong products.

## Your Break-Even ROAS by Profit Margin

- **10% margin** — requires 10.0× ROAS (1,000%) just to break even
- **20% margin** — requires 5.0× ROAS (500%) just to break even
- **30% margin** — requires 3.33× ROAS (333%) just to break even
- **40% margin** — requires 2.5× ROAS (250%) just to break even
- **50% margin** — requires 2.0× ROAS (200%) just to break even
- **70% margin** — requires 1.43× ROAS (143%) just to break even

### The uncomfortable reality

> If your business runs on a 20% margin, [a 'good' ROAS of 400%](/ecommerce/what-is-a-good-roas-for-ecommerce-uk-industry-benchmarks-for-2026/) still leaves you at 80% of break-even. You are losing money on every sale and calling it a win. POAS removes that ambiguity entirely by changing what you optimise for.

## What POAS Actually Is (The Trojan Horse Method)

Google Ads does not have a POAS bidding button. What it does have is Target ROAS — and you can use that infrastructure to optimise for profit instead of revenue by changing what you report as the conversion value.

Instead of telling Google an order was worth £100, you tell it the order was worth **£40** (after subtracting £60 in costs). Google's bidding algorithm still runs Target ROAS. It just thinks ROAS means profit on ad spend now, because that is what the conversion values represent.

This is the whole method. You are not building new bidding infrastructure. You are changing the number you feed into existing infrastructure so it optimises for the right thing.

## Implementing POAS: The Automated Path (Recommended)

1. **Choose your profit tracking tool** — Three tools do this job well: **ProfitMetrics** (straightforward, does exactly what it says), **Reaktion** (stronger on data visualisation), and **Pixel Manager for WooCommerce** (the best option if you're on WooCommerce). All three connect to your store and pass profit values to Google automatically.
2. **Enter your Cost of Goods Sold for every product** — This is the hard part — and the most important part. For every product, enter the cost to you: product cost, packaging, any per-unit fulfilment cost. If you skip this or use rough estimates, the tool assumes 100% margin and bids far too high. Take your time here.
3. **Let the tool create a new conversion action** — Once connected, the tool creates a new conversion in Google Ads — typically called 'POAS' or 'Gross Profit'. This is the conversion you will eventually make primary. Do not touch or delete your existing revenue conversion yet.

## Implementing POAS: The Manual DIY Path

1. **Capture the Google Click ID (GCLID)** — **Shopify:** Edit your theme.liquid to save the GCLID in a cookie, then pass it through as a cart attribute so it appears on every order export. **WooCommerce:** Install the 'HandL UTM Grabber' plugin, which captures the GCLID automatically and attaches it to orders.
2. **Track your cost of goods** — **Shopify:** You can store product costs natively in Shopify admin under each product variant. **WooCommerce:** Cost of Goods Sold is now built into WooCommerce core — turn it on under Settings > Advanced > Features. On an older version, install the 'Cost of Goods for WooCommerce' plugin instead.
3. **Export, calculate, upload** — Export your orders to CSV. Add a Profit column: Revenue − Cost − Shipping = Profit. Upload the file to Google Ads via the Conversions section, mapping your Profit column to 'Conversion Value'. Do this on a regular schedule — weekly works for most stores.

## The Overhead Gotcha (Get This Wrong and You'll Overbid)

Here is where most people stumble: they try to account for rent, wages, software subscriptions, and other fixed overheads inside the conversion value they send to Google. Do not do this.

Your fixed overheads exist whether you sell one unit or a thousand. Your Google Ads bid should not change based on costs that are unaffected by volume. Subtract fixed costs from your conversion values and you will underbid on every order.

**What to send Google:** Gross profit — Revenue minus Cost of Goods and direct fulfilment costs like shipping. This is the contribution margin: the money available to cover your fixed costs and, beyond that, generate actual profit.

**How to account for fixed costs:** Adjust your Target POAS instead. If fixed costs consume roughly 30% of your gross profit, you need a POAS of at least *1 ÷ (1 − 0.30) = 1.43, or 143%*, just to break even. Set your target above that to generate real profit.

## The Safe Switch Protocol: Three Phases Over Four Weeks

1. **Phase 1 — Observation (Weeks 1–3)** — Add your profit conversion action as a *secondary* conversion in Google Ads. Do not change your bidding strategy. Let both conversions run in parallel. After two to three weeks, compare the profit values being reported against your actual backend numbers. If they match, you are ready to proceed.
2. **Phase 2 — The Flip (Week 4)** — Make your profit conversion the *primary* conversion. Demote your revenue conversion to secondary. Your bidding strategy remains Target ROAS — nothing changes there. What changes is the value Google is now optimising for.
3. **Phase 3 — Reset Your Target (Critical Step)** — Do not carry your old ROAS target across. Pull your historical data for the previous month and calculate your *actual POAS* during that period. If it was 150%, [set your new target](/data/how-to-set-google-ads-targets-cpa-roas-2/) at 150%. If you leave the old target at 400%, Google will try to achieve £4 of profit for every £1 spent — almost certainly impossible — and your ads will stop spending entirely.

### Related services

- [Get a PPC audit](/ppc-audits/)
- [Talk to a PPC consultant](/ppc-consultant/)
- [PPC management](/ppc-agency/)

## Frequently asked questions

### What is POAS bidding in Google Ads?

POAS stands for Profit on Ad Spend. Instead of reporting order revenue as your conversion value, you report actual profit (revenue minus variable costs). Google's Target ROAS bidding then optimises for profit, so you scale what actually makes money rather than what generates the most turnover.

### How is POAS different from ROAS?

ROAS uses revenue as the optimisation signal. Two £100 orders look identical to Google even if one costs £90 to fulfil and the other costs £10. POAS strips out costs before reporting, so Google sees the difference and bids accordingly — more for high-margin orders, less for low-margin ones.

### Do I need third-party software to implement POAS?

No, but it makes things significantly easier. Tools like ProfitMetrics, Reaktion, and Pixel Manager for WooCommerce automate the profit calculation and pass values to Google in real time. The manual path — exporting orders, calculating profit in a spreadsheet, and uploading to Google — works but requires a consistent weekly process.

### What target should I set when I switch to POAS?

Calculate your actual POAS from the previous month using historical data. If Google was achieving 150% POAS across your existing campaigns, set your new target at 150%. Do not port across your old ROAS percentage — the numbers represent entirely different things and campaigns will stop spending if the target is unachievable.

### Should I include fixed overheads like rent and wages in my POAS conversion values?

No. Only include variable costs — Cost of Goods Sold and direct fulfilment costs like shipping. Fixed overheads are the same whether you fulfil one order or a thousand, so including them distorts your conversion values and causes underbidding. Account for fixed costs by setting a higher Target POAS instead.

### How long does it take to switch safely to POAS?

Allow four weeks minimum. Spend the first two to three weeks running your profit conversion as secondary alongside your existing revenue conversion, verifying the values match your backend. Switch profit to primary in week four, then reset your target based on your actual historical POAS — not your old ROAS target.

## Need Help Switching to POAS?

Migrating to profit-based bidding takes careful setup. Get it wrong and your campaigns stop spending; get it right and you stop wasting budget on high-revenue, low-margin products. I help ecommerce businesses make the switch cleanly — from COGS data entry through to target-setting and ongoing monitoring.

**Call 07410 907 104**