How to Calculate Your Blended ROAS Across Google, Meta, and TikTok

If you rely on platform-specific dashboards to dictate your ad spend, you are likely overspending. Google, Meta, and TikTok all utilize different attribution windows. When a user interacts with ads across all three platforms before purchasing, each platform claims 100% of the revenue.

To scale profitably in 2026, you must ignore individual platform metrics and calculate your Blended Return on Ad Spend (ROAS).

The Blended ROAS Formula

Blended ROAS tracks the actual cash leaving your business versus the total cash entering it. It is calculated as: Total Store Revenue / Total Ad Spend (Across all channels)

If you spend $1,000 on Google, $1,000 on Meta, and $500 on TikTok, your total spend is $2,500. If your Shopify dashboard reports $10,000 in total sales, your Blended ROAS is exactly 4.0x, regardless of what the individual ad networks claim.

Automating the Math

Instead of manually exporting CSVs from three different ad accounts every morning, you can forecast your cross-channel performance instantly.

Use our free Multi-Platform Ad Budget & ROAS Calculator to input your exact budget split. The tool will automatically calculate your blended Cost Per Acquisition (CPA) and total projected revenue based on real-time platform benchmarks.