Blended ROAS is return on ad spend calculated across all your paid advertising channels together, rather than for any one platform. Where per-channel ROAS tells you how Google or Microsoft individually is performing, blended ROAS tells you the overall return on your total advertising investment.
Formula
Blended ROAS = Total revenue from all paid channels / Total ad spend across all paid channels
For example: £3,000 in total paid revenue divided by £1,000 in total ad spend gives a blended ROAS of 3.
Worked example
In a month, you spend £600 on Google Shopping, £250 on Microsoft Shopping, and £150 on Meta, totalling £1,000.
Those campaigns together attribute £3,000 in revenue.
Blended ROAS = £3,000 / £1,000 = 3
For every pound spent across all channels, you return £3. Now look at each channel individually: Google ROAS is 4, Microsoft ROAS is 3.5, Meta ROAS is 1.2. The Meta campaigns are dragging the blended figure down, which you would not see from the per-channel view alone.
What good looks like
Blended ROAS benchmarks are as margin-dependent as per-channel ROAS, so there is no single number that is universally healthy. Its value is diagnostic rather than prescriptive:
- Use it to spot when one channel is weakening the whole. A blended ROAS that is significantly lower than your best-performing channel's ROAS is a signal that another channel is pulling it down.
- Track it over time. A falling blended ROAS with stable individual channel performance often means your channel mix has shifted toward less efficient spend.
- Pair it with total revenue. A blended ROAS of 5 on £100 of spend is not comparable to a blended ROAS of 3 on £50,000 of spend. Scale matters.
How Vendably calculates blended ROAS
Vendably computes a blended, merchant-level ROAS in its Intelligence compute by summing paid revenue and paid cost across all connected channels for the period. It surfaces this figure on the Intelligence dashboard alongside per-product ROAS, so you can see both the aggregate picture and the product-level detail in one place.
When no order feed is connected, order-derived revenue can fall back to Google Analytics 4 data. In that case, figures are at daily granularity rather than order-level granularity, which may affect comparisons with per-channel numbers from ad platforms.