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TikTok video checker

Free, no account · runs in your browser · last checked

Pick a video and this page reads its container, dimensions, duration and size in your browser, then checks them against what the TikTok Content Posting API documents as acceptable — video/mp4, video/quicktime or video/webm — and against the 4:5 frame a Facebook feed ad uses. The file never leaves your machine.

Aspect ratio = width ÷ height · 9:16 = 0.5625 · Meta feed 4:5 = 0.8

What does this actually check?

Four things, all read from the file itself: the container type, the pixel dimensions, the duration, and the size on disk.

It checks the container against the three content types TikTok's upload endpoint documents — video/mp4, video/quicktime, video/webm — rather than against the "MP4 only" advice most pages repeat. The API is broader than the folklore.

It checks the ratio against 9:16, which is a DISTRIBUTION recommendation and not an upload constraint: TikTok accepts a square or landscape file happily and then plays it letterboxed, which costs watch time rather than returning an error. That is the one spec no API response will ever warn you about.

Why does it not tell me the maximum duration?

Because there is not one. The TikTok API returns max_video_post_duration_sec PER CREATOR, from the Query Creator Info endpoint — the limit belongs to the account you are publishing to, not to the platform.

Any checker that hard-codes a single maximum is describing one account, or guessing. This one asks you for your own limit instead of inventing it, which is less satisfying and more accurate.

Why check the Meta frame at the same time?

Because a TikTok video that performs is worth putting ad spend behind, and the frames do not match: TikTok is 9:16, Meta's feed placement wants 4:5 at 1440 × 1800.

What breaks first when you re-upload the vertical master is not the frame, it is the text — burned-in subtitles positioned for a 9:16 safe area fall outside a 4:5 crop, and you only notice after the ad is live.

Frequently asked

What video formats does TikTok accept?
Through the Content Posting API, three content types are documented: video/mp4, video/quicktime and video/webm. MP4 with H.264 and AAC is the most predictable through TikTok's transcode.
Does my TikTok video have to be 9:16?
No — the API does not enforce a ratio. A non-vertical file uploads fine and then plays letterboxed in a full-screen vertical feed, which usually reduces watch time. It is a performance constraint, not a technical one.
What is the maximum length of a TikTok video?
It depends on the account. The API returns max_video_post_duration_sec for each creator, so there is no single number that is true for everyone.
Is my video uploaded when I check it here?
No. The browser reads the file's metadata locally and nothing is sent anywhere — you can confirm it in your network tab.

Where these numbers come from