Standard Definition
Target ROAS (Return on Ad Spend) is a Smart Bidding strategy in Google Ads that controls bids so that a defined return-on-ad-spend target value is achieved. The advertiser sets how much revenue should return per invested euro of advertising budget — e.g., a ROAS of 400 percent means €4 revenue per €1 ad spend. Unlike Target CPA, which treats all conversions as equivalent, Target ROAS considers different values of individual conversions. Prerequisite: conversion tracking must pass conversion values (order value, lifetime value, contribution margin) — without this data, Target ROAS doesn't work. Minimum volume: 50 conversions per month per campaign for statistically stable algorithm learning.
What this means in mandate practice
Target ROAS is operatively the most demanding Smart Bidding strategy — and at the same time the economically most precise.
First, the conversion value definition is decisive. Those who simply pass gross order value as conversion value overlook margin differences between products. Optimization means: pass margin-adjusted value (e.g., „order value × 0.35" as approximation of contribution margin), different value factors per product category if possible, or directly the contribution margin per order — when technical integration allows. A common mandate error: track all orders flat as „order value" even though margin spreads vary 20-60 percent.
Second, the target ROAS must match the margin structure. With 30 percent gross margin on a product, a target ROAS of 400 percent (equals 25 percent ad cost share) is a balanced calculation — net zero without growth contribution. Realistic target ROAS values depend directly on margin structure. Advertisers who set high target ROAS values without margin awareness press the algorithm into too narrow efficiency zones — volume breaks away.
Third, Performance Max uses Target ROAS as the central steering variable. In Performance Max campaigns, Target ROAS is often the only operative steering element — keyword selection, audience steering, and ad optimization are largely left to the algorithm. This makes correct Target ROAS setting in Performance Max the decisive steering discipline. Calvarius works here with gradual adjustments over several weeks, not with jump settings — rapid Target ROAS changes lead to algorithm re-learning with 1-3 weeks of volume volatility.