How to Calculate ROAS (Return on Ad Spend): A Simple Step-by-Step Guide
Return on Ad Spend, or ROAS, is a simple way to measure how much revenue your advertising generates compared with how much you spend on the campaign.
It can help businesses compare advertising performance across platforms such as Google Ads, Facebook Ads and other paid marketing channels.
In this guide, you’ll learn how to calculate ROAS using a simple formula, work through a practical example, understand what the result means, and avoid common calculation mistakes.
By ToolNestPro | Updated September 2026
What Is ROAS?
ROAS stands for Return on Ad Spend. It measures the amount of revenue generated for every amount spent on advertising.
For example, if a business spends £500 on an advertising campaign and generates £2,000 in revenue from that campaign, the ROAS shows how much revenue was returned for each £1 spent.
ROAS focuses specifically on advertising performance, which makes it useful for comparing campaigns, ad platforms and marketing channels.
How to Calculate ROAS
ROAS is calculated by dividing the revenue generated from an advertising campaign by the amount spent on that campaign.
Formula:
ROAS = Revenue from Ads ÷ Advertising Cost
For example, if you spend £400 on advertising and the campaign generates £1,600 in revenue:
ROAS = £1,600 ÷ £400 = 4
This means the campaign generated £4 in revenue for every £1 spent on advertising.
You may also see ROAS written as a ratio, such as 4:1, or as a percentage, such as 400%.
How to Interpret Your ROAS
A ROAS result tells you how much revenue was generated for every £1 spent on advertising.
For example:
ROAS of 2 means £2 in revenue was generated for every £1 spent.
ROAS of 4 means £4 in revenue was generated for every £1 spent.
ROAS of 6 means £6 in revenue was generated for every £1 spent.
A higher ROAS generally means the campaign is generating more revenue compared with its advertising cost.
However, ROAS does not tell you whether the campaign was actually profitable, because it does not include other business costs such as product costs, wages, delivery, software, fees or overheads.
That is why ROAS should be used alongside other business figures when evaluating overall performance.
ROAS vs ROI: What’s the Difference?
ROAS and ROI are both used to measure performance, but they focus on different things.
ROAS measures the revenue generated from advertising compared with the amount spent on that advertising.
ROI measures the overall return from an investment after considering the cost of that investment.
For example, a campaign may have a strong ROAS because it generated a lot of revenue compared with ad spend, but the overall ROI may be lower once other business costs are included.
ROAS is especially useful for comparing advertising campaigns, while ROI is broader and can be used to evaluate many different types of investments.
Common ROAS Calculation Mistakes
ROAS is a simple calculation, but a few common mistakes can make the result misleading.
One mistake is using total business revenue instead of the revenue generated specifically by the advertising campaign.
Another is forgetting to include the full advertising cost, such as campaign spend across multiple ads or platforms.
It is also important not to confuse ROAS with profit. A campaign can generate a high ROAS but still produce a low profit if other business costs are high.
Finally, make sure you are comparing revenue and advertising spend from the same time period and campaign.
Calculate Your ROAS
Frequently Asked Questions
What does a ROAS of 4 mean?
A ROAS of 4 means the campaign generated £4 in revenue for every £1 spent on advertising.
Is a higher ROAS always better?
A higher ROAS generally means more revenue is being generated compared with ad spend, but it does not automatically mean the campaign is highly profitable because other business costs still need to be considered.
Can ROAS be negative?
ROAS itself is not normally expressed as a negative number because it compares revenue with advertising spend. If a campaign generates no revenue, the ROAS would be 0.
Use our free ROAS Calculator to quickly compare your advertising revenue with your ad spend and see how much revenue you generate for every £1 spent.