What Google says
In Google's own words: “Content suitability settings provide additional filtering to help you find the right fit for your product or brand.” (Google help center)
The three inventory types
Maximum serves across all available inventory, subject to Google's content policies, with highly sensitive content excluded automatically. Moderate additionally excludes strong profanity, dramatized violence and sexually suggestive themes. Limited goes furthest, excluding moderate profanity and sexually suggestive themes even inside mainstream content like music videos. Google renamed Expanded to Maximum and Standard to Moderate; the exclusions did not change with the names.
What it does and doesn't protect
The Video Ad Safety Promise applies to all three tiers, so the most controversial content is excluded regardless of setting. What you trade by tightening is reach: Google's own estimate panel shows reduced inventory, reduced impressions and an increased CPM, because a smaller pool costs more to buy. It is also a blunt instrument, and no substitute for placement exclusions and a weekly placement review. We compare the tiers in Google Ads inventory types explained. Inventory types do not apply to App campaigns or YouTube Sponsorship campaigns, and Sponsorships always run on Moderate inventory.
A worked example
Say a YouTube campaign has a $6,000 budget and buys impressions at a $12 CPM on Moderate inventory, which is 500,000 impressions. If moving to Limited inventory lifts the CPM to $15, the same $6,000 buys 400,000 impressions, 20% less reach for a stricter filter. That trade is worth making for a brand with genuinely strict suitability rules, and rarely for a B2B advertiser whose real risk is irrelevant placements, which placement exclusions handle better.
Common questions
What is the difference between Maximum, Moderate and Limited inventory?
Maximum allows all available inventory under Google's content policies. Moderate also excludes strong profanity, dramatized violence and sexually suggestive themes. Limited excludes moderate profanity and suggestive themes even in mainstream content.
Is Maximum inventory unsafe for brands?
Not in the way the name suggests. The Video Ad Safety Promise applies across all inventory types, so content like profanity in titles or thumbnails, nudity, drug content and terrorism is excluded at every tier. The one exception Google notes: coverage of terrorism or sensitive current events from authoritative news sources can run in Moderate inventory.
Where is content suitability in Google Ads?
Go to Content suitability in the Tools menu. For Display and Video campaigns the controls are set at the account level, including inventory type, excluded content themes, up to 1,000 excluded content keywords and up to 65,000 excluded placements.
Does content suitability apply to YouTube Shorts?
Partly. Inventory type applies to Shorts, but content keyword and content type exclusions do not, and Google says content exclusions may provide limited coverage of Shorts and in-feed ads.
What does ad suitability mean on YouTube?
It is the layer of brand controls on top of YouTube's monetization policies: content that breaks policy can't carry ads at all, and suitability settings let you exclude content that is allowed but not right for your brand. Inventory type is the main dial, with Maximum, Moderate and Limited.