4 Facebook Ads custom metrics for e-commerce 

After launching your Facebook campaigns, you can analyse the data using the many metrics available in Ads Manager. But which metrics actually matter for your e-commerce business? And how do you create custom metrics that give you more insight?

In this blog we share 4 powerful custom metrics that every e-commerce advertiser should have in their Ads Manager.

Why custom metrics?

Facebook's default metrics are useful, but they don't always match the specific goals of your business. With custom metrics you can:

• Calculate your own KPIs directly in Ads Manager
• Make better decisions without having to export data to Excel
• Compare campaigns based on what actually matters for your business

How do you create custom metrics?

In Ads Manager, go to 'Columns' → 'Customise columns' → 'Create custom metric'. You can then build your own formula using existing metrics.

Custom metric 1: Net ROAS

Standard ROAS (Return on Ad Spend) measures revenue divided by ad spend. But this doesn't account for your costs. Net ROAS subtracts your average margin:

Formula: Purchase value / (Ad spend / gross margin %)

For example: if your average margin is 40%, your Net ROAS shows the actual profitability of your campaigns.

Custom metric 2: Blended CPA

Your Cost Per Acquisition in Facebook often doesn't tell the complete story, because not all conversions happen directly via the ad. Blended CPA combines your ad spend with all conversions:

Formula: Total ad spend / Total orders (including organic and email)

This gives a more realistic picture of the actual cost of a customer.

Custom metric 3: Add to Cart Conversion Rate

This metric shows what percentage of people who view your product actually add it to their cart:

Formula: (Add to cart / Landing page views) × 100

A low rate indicates a problem with your product page or offering. A high rate but low purchase rate indicates a problem with your checkout.

Custom metric 4: Video Through Rate

If you use video ads, this metric is essential. It shows what percentage of people watch your video to at least 75%:

Formula: (75% video views / Video impressions) × 100

A low Through Rate means your video isn't engaging enough to keep viewers watching. A high rate means your message is resonating.

How to use these metrics

Add these custom metrics to your standard column view in Ads Manager. This way you see them immediately when you review your campaigns.

Use the metrics to:

• Compare campaigns and ad sets based on profitability (not just ROAS)
• Identify which landing pages need improvement (Add to Cart CVR)
• Optimise your video content based on actual engagement (Through Rate)
• Make more informed decisions about scaling or pausing campaigns

Conclusion

Facebook Ads offers enough data — the challenge is extracting the right insights. These 4 custom metrics give you a much sharper picture of what's actually working in your campaigns.

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