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Aspect Ratio 9:16 — Definition

9:16 is the vertical aspect ratio used by Stories, Reels, and TikTok. It is the only aspect ratio that fills a portrait phone screen.

9:16 is the vertical aspect ratio used by Stories, Reels, and TikTok — and is the only aspect ratio that fills a portrait phone screen edge to edge. The "9" is the width and the "16" is the height, expressed as a ratio. On a 390 × 844 logical-pixel iPhone, 9:16 maps cleanly to the full screen.

Other aspect ratios are letterboxed when displayed in 9:16 surfaces. A 1:1 square creative shows with horizontal black bars above and below; a 4:5 nearly-portrait creative shows with smaller bars. Letterboxing reduces visual impact on fast-scroll surfaces because the eye registers the bars as "not native content."

The strategic implication: if your campaign includes 9:16 placements, plan native 9:16 creative. Don't rely on 1:1 or 4:5 fallbacks. The performance gap between native 9:16 and letterboxed creative is significant — typically 15–30% on engagement metrics.

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9:16 fills the portrait phone screen edge to edge

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Where 9:16 applies

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Source: https://ads.tiktok.com/help/article/creative-specifications · Last verified 2026-04-15.

The native-format premium

Audiences perceive native 9:16 creative as authentic; they perceive letterboxed creative as repurposed. The bias is strong enough to show up in CTR, completion rate, and brand-lift studies.

FAQ

What other aspect ratios do social platforms use?
1:1 (square) for Feed, 4:5 (portrait) for Feed (preferred), 16:9 (landscape) for video on web. 9:16 is mobile-vertical-only.
Can I use 9:16 on Feed placements?
Yes. Meta Feed crops 9:16 to 4:5. The full 9:16 doesn't display on Feed but the 4:5 crop does.
What's the safe canvas inside 9:16?
Varies by placement. TikTok In-Feed is roughly the central-right rectangle (30%–86% X by 8%–78% Y).
Are dimensions other than 1080 × 1920 acceptable?
Yes — any 9:16 ratio works. Most platforms recommend at least 1080 × 1920 for quality.