What is ROAS and how do you calculate it?

ROAS (return on ad spend) is the metric that tells you whether your advertising is earning more than it costs. It measures how much revenue you generate for every pound you spend on ads. A ROAS of 4:1 means you earn GBP 4 for every GBP 1 spent.

What is ROAS?

Return on ad spend is a simple calculation: total ad revenue divided by total ad cost. If you spend GBP 1,000 on Google Ads and those ads generate GBP 5,000 in revenue, your ROAS is 5:1. You made five times what you spent.

The formula is straightforward:

ROAS = Revenue from ads / Cost of ads

The result is expressed as a ratio. A ROAS of 3:1 is common shorthand for "three pounds earned for every one pound spent". You can also express it as a percentage: 3:1 = 300 percent ROAS.

What a good ROAS looks like

There is no universal number because margins differ by business model. A retailer selling physical goods with a 40 percent margin needs a higher ROAS than a service business that spends nothing on materials.

Here are realistic benchmarks:

• Ecommerce with physical products: 4:1 to 6:1 is strong. Lower margins mean you need more revenue per ad pound to break even.
• Services and high-ticket sales: 3:1 to 5:1 is common. A client paying GBP 5,000 for a website build only needs to fill one enquiry to make the numbers work.
• Lead generation: 2:1 to 4:1. When each lead has a high conversion rate downstream, a lower headline ROAS can still be profitable.
• Brand awareness campaigns: ROAS is not the right metric here. Use impression share, reach and cost per thousand instead.

How ROAS differs from ROI

ROAS and ROI are often used interchangeably, but they measure different things. ROAS looks only at ad spend versus the revenue that spend generated. It is a channel-level view.

ROI takes a wider view. It includes all the costs that went into earning that revenue, not just the ad spend. If you spent GBP 1,000 on ads and GBP 500 on a freelancer to create the campaign, your ROAS is still based on the GBP 1,000 ad spend, but your ROI is lower because you factor in the full GBP 1,500 cost.

For most advertisers, ROAS is the more useful day-to-day metric. It tells you whether each channel is performing in isolation. ROI is better for quarterly or annual reviews when you assess total marketing efficiency.

How to track and improve ROAS

The simplest way to track ROAS is through conversion tracking in Google Ads. Set up the Google tag on your thank-you or order confirmation page so the platform can attribute revenue to specific campaigns and keywords.

To improve ROAS, focus on the levers within your control. Cut the keywords that spend budget without converting. Write ad copy that matches the searcher's intent. Use negative keywords to block irrelevant searches. And test your landing pages because the best ad in the world cannot fix a page that fails to convert.

Victory Digital's ad management for clients like Home Instead Basingstoke has shown how focused ad copy, audience targeting and conversion tracking can deliver measurable returns. In that campaign, ad conversions grew by over 3,400 percent through a structured approach to keyword management, ad testing and landing page alignment.