- Meta: 4:5 and 1:1 for the feed placements, 9:16 for stories and Reels.
- TikTok: 9:16 is recommended, 1:1 and 16:9 are possible.
- Google (Demand Gen, YouTube): 16:9, 1:1 and 9:16, vertical also for Shorts. Google recommends supplying every ratio. The details are in the Google Ads Help.
As of 29 October 2026, from the platforms' help pages and from industry guides. Ad platforms change their requirements; check ratio, length and file size in your ad account before you upload.