Turn long videos into TikTok clips
A long recording usually holds a handful of moments that work on TikTok: a quick story, a strong opinion, a clear answer. Reeltopus finds them in the transcript, cuts each one so it finishes its thought, reframes it to vertical with the speaker in frame, and adds captions that stay above TikTok's caption and button area. Reeltopus is in early access, so join the waitlist to try it.
TikTok at a glance
- Maximum length
- UnclearTikTok's help page for TikTok Studio lists uploads up to 30 minutes, as MP4 or WebM, 720 × 1280 or larger and under 10 GB. TikTok's other pages give different limits by account and by app, web or API, so check your own upload screen.Checked 17 October 2026 · Source
- Posting from other apps
- Through TikTok's posting API, every creator can post 3-minute videos and some can post 5 or 10 minutes. Apps can send up to 10 minutes, and you can trim in TikTok to fit your account's limit.Checked 17 October 2026 · Source
- File formats (API)
- MP4 (recommended), WebM or MOV. H.264 is recommended. At least 23 fps, 360 to 4,096 pixels on each side, and up to 4 GB.Checked 17 October 2026 · Source
- Aspect ratio
- UnclearNone of the TikTok pages we could check state a required aspect ratio for regular posts. Vertical 9:16 at 1080 × 1920 fills the screen. TikTok publishes no pixel safe zones, so our margins are measured from the app.Checked 17 October 2026
- Auto captions
- Creators select auto captions on the editing page after uploading or recording, and can edit the text once it's generated. Viewers can turn captions off from the share panel. This comes from TikTok's 2021 announcement.Checked 17 October 2026 · Source
- Caption length
- UnclearPosts made through TikTok's API can have captions up to 2,200 characters. The TikTok pages we could check don't state the limit in the app.Checked 17 October 2026 · Source
- Drafts from other apps
- Apps can send a video to TikTok as a draft. You get an inbox notification, finish editing in TikTok and post it yourself.Checked 17 October 2026 · Source
- Scheduling
- UnclearTikTok's Video Scheduler announcement described scheduling from the web uploader up to 10 days ahead. Newer TikTok pages mention longer windows, so check the schedule option in your account.Checked 17 October 2026 · Source
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What works on TikTok
Say the hook in the first line
Open on the sentence that makes someone stop: the claim, the question or the surprising part of the story. Cut the warm-up that worked in the long version.
Leave room on the right and at the bottom
TikTok's button column on the right is wide, and the username, caption and sound sit at the bottom. Keep faces and captions in the upper middle of the frame.
Finish the thought
A clip that stops before the punchline feels like a trailer. Include the payoff, even if the clip runs a little longer.
Write the caption in plain words
Describe what the clip is about in the words someone would type into TikTok search, then add 3 to 5 specific hashtags rather than a long generic list.
Use one set of captions
If your clip has burned-in captions, skip TikTok's auto captions or turn them off, so two lines of text don't stack on top of each other.
How Reeltopus prepares clips for TikTok
Vertical with the speaker in frame
Active-speaker tracking reframes 16:9 footage to 9:16 with a smooth camera path. Podcasts and interviews with two people get an automatic split screen.
Captions above TikTok's overlays
Burned-in animated captions sit above the caption and username area and away from the right-hand buttons. Because TikTok publishes no safe zones, we use conservative margins measured from the app.
Complete moments, at the length you want
The clip brain checks each pick has a setup and a payoff, so it doesn't end before the punchline. Trim by deleting words in the transcript, or ask in plain words: "make it 40 seconds".
Captions that match what was said
Transcription covers 100+ languages, including mixed speech like Hinglish. Unsure words are flagged, and fixing a word once updates every clip. Filler words and silences can be cut per clip.
Posting: Posting to TikTok, Instagram, YouTube, LinkedIn, X, Threads and Facebook is rolling out platform by platform, switching on as each platform's app approval completes. For TikTok it will start as "send to TikTok drafts": the clip lands in your TikTok inbox, and you add a sound, check it and post from the app. Until then, download the MP4 and upload it to TikTok yourself, which works from day one.
Free tools
Aspect ratio and safe-zone calculator
Exact pixel sizes and UI safe zones for YouTube Shorts, Instagram Reels, TikTok, LinkedIn and X, plus a crop calculator and ffmpeg command for turning 16:9 video into 9:16.
Hook line generator
Paste a paragraph from your video or script and get 5 opening hook lines for TikTok, Reels and Shorts, written by AI. Free, no sign-in.
Hashtag suggester
Describe your video and get relevant hashtags grouped for TikTok, Instagram Reels, YouTube Shorts or LinkedIn, with no spam tags. Free AI tool, no sign-in.
Video length and reading-speed calculator
Find out how long your script runs at your speaking pace, how many words fit a 15, 30 or 60-second clip, and whether your captions are too fast to read.
Questions
How long can a TikTok video be?
It depends on your account and how you post. TikTok's Studio help lists uploads up to 30 minutes, while its posting API allows 3 minutes for everyone and 5 or 10 minutes for some creators. Your upload screen shows your limit. Most clips cut from long videos are far shorter anyway.
Can I turn a YouTube video into TikToks?
Yes, if it's your video or you have the rights. Upload the original file to Reeltopus and it picks the moments, reframes them to 9:16 and adds captions, ready to download for TikTok.
What size should a TikTok be?
1080 × 1920 (9:16) fills the screen. TikTok doesn't publish safe zones, so keep faces and text away from the right-hand buttons and the bottom caption area. The free aspect ratio calculator shows our measured margins.
Will Reeltopus post straight to TikTok?
Posting is rolling out platform by platform. For TikTok it will start by sending clips to your TikTok drafts, so you can add a sound and post from the app. Until then, download and upload the clip yourself.
Should I use TikTok's auto captions or burned-in captions?
Either works, but not both at once. TikTok's auto captions are generated in the app and you can edit them there. Burned-in captions let you choose the style and keep keyword highlights, and they look the same everywhere you post the clip.
Make TikTok clips from every long video.
Join the waitlist for early access. The free plan includes 2 upload hours a month.