Google Ads smart bidding inflates ROAS but can harm profits

Google Ads smart bidding is common for boosting your ad returns but it can inflate your return on ad spend (ROAS) while actually hurting profits. This happens because smart bidding optimises for conversions it can measure, not the profit margins behind them.

Search Engine Land highlighted on 4 November 2026 that smart bidding can’t see margins if your conversion tracking doesn't include them. It only knows what it tracks. That means smart bidding might push ads that look good on ROAS reports but drain your profits in reality. Read more on Search Engine Land.

## Why does this happen?
Google Ads smart bidding uses machine learning to automatically adjust your bids aiming to maximise conversions or ROAS. However, if your conversion tracking doesn’t include profit margin data, it may prefer conversions with low or no real profit.

This inflates ROAS numbers but reduces actual profit. For small businesses where every penny counts, this is a risk.

## What can you do this week?
First, review your conversion tracking and add any profit or margin data if you can. This might involve passing margin values with tools like Google Tag Manager.

Second, look into margin-based bidding strategies that factor profit margins into bid decisions. Combining this with improved conversion tracking helps smart bidding protect your profits.

Try my free ROAS and break-even ROAS calculator and profit and margin pricing calculator to understand your margins better.

If you want advice on setting this up, check out my Google Ads services or get in touch here (/#enquiry).

## What it means for you
Smart bidding isn’t set-and-forget. It needs accurate margin data to really improve profits, not just ROAS. This week, start by improving your tracking and running margin calculations. Protect your budget from costly bids on low-profit conversions.