What is blended ROAS?
Blended ROAS measures your total revenue against your total ad spend across every channel — not just what a single ad platform claims it drove. It's also called MER (marketing efficiency ratio) and is increasingly used as the north-star metric for performance marketers who want a number that can't be gamed.
Blended ROAS = Total revenue ÷ Total ad spend
If your business made $120,000 last month and you spent $40,000 on ads across Meta, Google, and TikTok combined, your blended ROAS is 120,000 ÷ 40,000 = 3x.
How to calculate blended ROAS (step by step)
- Get total revenue — your actual top-line sales for the period. Use your accounting or payment processor, not ad platform dashboards.
- Sum all ad spend — Meta Ads Manager + Google Ads + TikTok Ads + any other paid channels. Include retargeting, brand, and prospecting — everything.
- Divide total revenue by total ad spend — that's your blended ROAS.
That's it. No attribution windows, no view-through vs click-through debates, no platform-specific counting rules. Real money in, real money out.
Worked example: Multi-channel DTC brand
A DTC brand running ads across four channels:
| Channel | Ad spend | Platform-reported ROAS | Platform-reported revenue |
|---|---|---|---|
| Meta (Facebook/IG) | $18,000 | 4.5x | $81,000 |
| Google (Search + Shopping) | $14,000 | 5.0x | $70,000 |
| TikTok | $5,000 | 3.0x | $15,000 |
| $3,000 | 2.5x | $7,500 | |
| Sum of platform claims | $40,000 | — | $173,500 |
| Actual total revenue | — | — | $120,000 |
| Blended ROAS | — | — | 3.0x |
The platforms collectively claim $173,500 in revenue — $53,500 more than the business actually made. That's attribution overlap: Meta and Google both taking credit for the same conversion. Blended ROAS uses the real $120,000 figure and can't be inflated. At 3x blended, the brand is likely profitable (depending on margin), but nowhere near the 4.3x implied by averaged platform ROAS figures.
Tracking blended ROAS over time
| Month | Total revenue | Total ad spend | Blended ROAS | Trend | |---:|---:|---:|:---| | January | $100,000 | $35,000 | 2.86x | Baseline | | February | $115,000 | $38,000 | 3.03x | ↑ Scaling efficiently | | March | $120,000 | $45,000 | 2.67x | ↓ Scaling, but blended slipping | | April | $130,000 | $42,000 | 3.10x | ↑ Pulled back spend, revenue still growing |
In March, the brand pushed spend to $45K but blended ROAS dipped — a signal to pull back to the $38-42K range where blended holds above 3x. In April, revenue continued growing at lower spend (organic catch-up, seasonality, or better targeting), pushing blended to 3.1x. This is the weekly/monthly pattern: push spend, watch blended, adjust.
Why blended ROAS beats platform ROAS
Every ad platform reports its own ROAS — and they routinely over-claim, because Meta and Google both take credit for the same conversion. Add up their reported revenue and it can exceed your actual sales. Blended ROAS sidesteps attribution games entirely: it uses real money in versus real money out, so it can't be double-counted. Many operators now treat blended ROAS (sometimes called MER, marketing efficiency ratio) as their north-star metric and use platform ROAS only for relative, in-channel optimization.
Blended ROAS by business type
DTC ecommerce brands often target 3x–5x blended ROAS at scale, but acceptable ratios depend heavily on gross margin — use break-even ROAS (1 ÷ margin) as your floor. Subscription SaaS may run lower blended ROAS during growth because LTV unfolds over months; pair blended ROAS with LTV:CAC instead of judging on revenue alone. Marketplace or low-margin retail needs higher blended ROAS (4x+) to survive after product cost.
When platform ROAS looks great but blended ROAS doesn't
This gap is the classic sign of attribution overlap: Meta reports 6x, Google reports 5x, but total revenue only supports 2.5x blended. It can also mean organic and direct revenue aren't growing with paid spend — you're buying the same customers twice. When you see this pattern, trust blended ROAS for budget decisions and use platform ROAS only to compare ad sets within one channel. Pair with the single-channel ROAS calculator for the ad-set view and the marketing ROI calculator when you need to factor in margin.