- TikTok Reels ads run best in 9:16 vertical at a minimum of 540×960 px.
- Three aspect ratios are accepted: 9:16 (recommended), 16:9, and 1:1.
- Max file size is 500 MB. Minimum bitrate is 516 kbps.
- Keep logos and text in safe zones — TikTok UI overlays cover the edges.
- Coinis Revise Smart Resize preps any ad image for the right ratio in one click.
- TikTok direct publishing is on the Coinis roadmap — Smart Resize works today.
TikTok Reels ads reject assets that miss the spec. Wrong ratio, wrong size, wrong format. Any of those will stop your ad before it runs.
This guide covers every dimension, every limit, and every common mistake. Then it shows you a faster path.
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TikTok Reels Ad Specifications: The Three Aspect Ratios
Per TikTok's Business Help Center, in-feed video ads accept three aspect ratios. Pick the one that matches your source footage.
Vertical (9:16) — The Recommended Format
Vertical is the native TikTok experience. Use it for almost every Reels ad.
- Aspect ratio: 9:16
- Minimum resolution: 540 × 960 px
Full-screen vertical fills the entire phone display. No black bars. No wasted space. It looks like organic content, which is exactly the point.
Horizontal (16:9) — For Wider Screens
Horizontal works if you're repurposing a landscape asset from YouTube or a TV spot.
- Aspect ratio: 16:9
- Minimum resolution: 960 × 540 px
Horizontal shows smaller on mobile with black bars above and below. It rarely outperforms vertical on TikTok.
Square (1:1) — An Alternative Option
Square is a flexible fallback for assets you already have in that format.
- Aspect ratio: 1:1
- Minimum resolution: 640 × 640 px
Square travels well across platforms. Use it when you need one asset to cover multiple channels.
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Step-by-Step: How to Resize Your Video for TikTok Reels Ads
Step 1: Check Your Source Video Dimensions
Open the file in any video editor or right-click and check properties. Note the current width, height, and aspect ratio before touching anything.
Step 2: Choose Your Target Aspect Ratio
Pick 9:16 for most TikTok ads. Pick 16:9 only for landscape repurposing. Pick 1:1 when you need cross-platform reuse from a single export.
Step 3: Resize Using a Video Editor or Resizing Tool
Set the canvas to your target ratio. Crop or reframe so the key action stays centered. Never stretch a 16:9 clip to fill a 9:16 frame. That distorts faces and products. Crop and reframe instead.
Step 4: Verify File Size and Technical Specs
Before uploading, confirm:
- File size: 500 MB or under
- Minimum bitrate: 516 kbps
- Format: MP4, MOV, MPEG, 3GP, or AVI
- Duration: up to 60 seconds per TikTok's current documentation
Step 5: Test in TikTok's Ad Preview
Upload the resized video in TikTok Ads Manager and use the built-in preview. Check that nothing important is hidden behind UI overlays before you spend a cent.
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Critical File Requirements for TikTok Ads
Video Format and Codec Support
TikTok accepts five formats: MP4, MOV, MPEG, 3GP, and AVI. MP4 is the safest choice. It compresses well and uploads reliably.
File Size Limits
Maximum file size is 500 MB. Most compressed MP4 exports sit well below that. If your file is too large, lower the bitrate or reduce resolution while staying above the minimum.
Bitrate Minimums
TikTok requires at least 516 kbps. Go higher when you can. Higher bitrate means sharper motion and less compression noise in fast-moving product shots.
Safe Zones to Avoid Cropping
TikTok overlays a profile icon, caption text, and share buttons on the right side and bottom of the video. Place text, logos, and key visuals away from those edges. TikTok provides safe zone templates inside Ads Manager. Download and use them.
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Common Resizing Mistakes and How to Avoid Them
Scaling Without Proper Aspect Ratios
Stretching a landscape clip to portrait distorts everything. Always crop and reframe. Your subject should still read clearly after the crop.
Ignoring Safe Zones for Text and Branding
A price callout or logo sitting at the bottom of the frame gets buried under TikTok's caption UI. Keep critical elements in the center of the screen, away from all four edges.
Exceeding File Size or Bitrate Limits
A file over 500 MB fails to upload. A file below 516 kbps looks blurry on playback. Compress early. Verify specs before your final render, not after.
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Faster Way: Automated Resizing with Coinis Revise
Manual resizing means one export per format. Every platform has different rules. It adds up fast.
Coinis Revise handles it with Smart Resize. Upload an ad image, pick your target dimensions, and Revise adjusts the canvas and crops it intelligently. No manual dragging. No export loop.
Use Smart Resize to prep a TikTok-ready vertical creative. Then repurpose the same asset for Facebook Feed, Instagram Stories, or Google Display in the same workflow. One image, every format, a few clicks.
Coinis does not publish directly to TikTok today. Direct TikTok campaign launch is on the roadmap. Smart Resize gets your creative pixel-perfect so you can upload to TikTok Ads Manager confident it will pass review.
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Or skip the steps.
Coinis Revise edits any ad image with AI. Move text. Change text. Swap colors. Erase objects. Translate to any language. One click each.
No design skills. No Photoshop. One click.
15 AI tokens a month. No credit card.
Frequently Asked Questions
What is the best aspect ratio for TikTok Reels ads?
9:16 vertical is the recommended format. It fills the full phone screen and matches how users naturally scroll TikTok. The minimum resolution for 9:16 is 540×960 px.
What video file formats does TikTok accept for ads?
TikTok accepts MP4, MOV, MPEG, 3GP, and AVI. MP4 is the most reliable choice for upload compatibility and file size.
What happens if I upload a video with the wrong aspect ratio?
TikTok may crop or letterbox your video, cutting off text, logos, or key visuals. Always resize to the correct ratio before uploading to TikTok Ads Manager.
Can I use one resized video for both TikTok and Instagram?
Not from the same file. TikTok and Instagram Stories both use 9:16, so the ratio matches. But you should verify each platform's specific minimum resolution and file size before uploading.