Trim a video
Almost every phone recording starts with two seconds of reaching for the button and ends with three of walking back. Cut both.
Everything happens inside your browser, using your own computer’s memory. Your file is never uploaded, never stored, and nothing is sent to us — so there is no limit on how often you use this.
How trimming works
At a glance
- Opens
- MP4, MOV, WebM, MKV — any video your browser can read
- Saves
- Exact cut: MP4. Fast cut: the same type as your file
- Keeps
- One continuous stretch — a start and an end
- Exact cut
- Re-encoded, lands on the frame you chose
- Fast cut
- Copied untouched, seconds even on a large file, may start a moment early
- Shortcuts
- Keep the first 15, 30, 45 or 60 seconds
How it works
Video is not stored as a stack of complete pictures. Every so often there is a keyframe — a full picture — and the frames in between are stored as the changes since the last one. That is how a minute of video fits in a few megabytes, and it decides how a cut can be made.
A fast cut copies the video without decoding it, so it has to begin on a keyframe: the one just before the moment you chose. It takes seconds and keeps the original quality, but the start can land up to a second or two early. An exact cut decodes the video and encodes it again from the frame you chose, so the first frame is exactly yours.
Step by step
- Drop the videoIt opens in this tab. Nothing uploads. The first time, the browser downloads the 32 MB video engine and keeps it.
- Set the start and endType the seconds, or tap “keep the first 15, 30, 45 or 60 seconds”. The line under the fields shows exactly what will be kept.
- Exact or fastLeave “Cut exactly where I asked” on when the first frame matters. Turn it off to shave a long tail off in seconds.
- Trim and downloadKeep the tab open while it works. The finished file stays in this browser until you press Delete.
Which setting for which job
| If you are… | Choose |
|---|---|
| The opening of a short — the first frame matters | Exact cut |
| Shaving minutes off the end of a long recording | Fast cut |
| A very large 4K file that runs out of memory | Fast cut — nothing is decoded, so it copes with far larger files |
| You only need the hook | Keep the first 15 seconds |
| A typical short | Keep the first 30 seconds, then adjust the start |
| Removing a piece from the middle | Not this tool — that is joining two pieces, which is editing |
Under the hood
The technical detail, for anyone who wants to know exactly what happens to their file. Each line first says it plainly.
Keyframes and GOPs
Full pictures, with changes in between.
An encoder stores a complete frame (a keyframe, or I-frame) at intervals and describes the frames between as differences. One keyframe and its dependants form a group of pictures (GOP); phones typically place a keyframe every second or two.
Fast cut (stream copy)
Seconds, and no quality change.
With -c copy the compressed frames are copied as they are. A copy can only begin on a keyframe, because the frames after it make no sense without it — hence the early start.
Exact cut (re-encode)
Frame-accurate.
The seek (-ss) is placed before the input, so ffmpeg jumps to the nearest keyframe and decodes forward to your exact time; from there the video is re-encoded with libx264 (veryfast, CRF 23) and the sound as AAC at 128 kbps.
Container kept on a fast cut
Nothing changes that does not have to.
A fast cut keeps your file's own type — MP4, MOV, WebM or MKV. An exact cut is saved as MP4, since it is being re-encoded anyway and MP4 plays everywhere.
Fast start
Plays before it has finished loading.
MP4 and MOV results get their index (the moov atom) moved to the front, so a preview can start at once.
Platform specs
How long each platform lets a video run. Trim to fit before you upload.
| Platform | Shape | Resolution | File size | Length | Format |
|---|---|---|---|---|---|
| Instagram Reels | 9:16 | 1440 × 2560 recommended | Up to 4 GB | Up to 15 minutes | MP4 or MOV · H.264 · AAC stereo, 128 kbps or more |
| TikTok | 9:16 recommended | 540 × 960 or larger | Up to 500 MB | — | MP4, MOV, MPEG, 3GP or AVI |
| YouTube Shorts | Vertical or square | — | — | Up to 3 minutes | — |
From each platform's own published specifications (Meta Ads Guide, TikTok Ads video specifications, YouTube Help), checked September 2026. “—” means the platform does not state it. Platforms change these; check before a big campaign.
If something goes wrong
| What you see | Why | What to do |
|---|---|---|
| My fast cut starts a second earlier than I asked | A copy has to begin on a keyframe, and the nearest one was before your start. | Tick “Cut exactly where I asked” for a frame-accurate start. |
| “Too large to cut frame-exactly in a browser” | An exact cut re-encodes every frame and ran out of the memory a browser gives one page. | Untick the exact option — the fast cut copes with far larger files — or shrink the file with Compress first. |
| The first frame is black or frozen for a moment | A fast cut began on the keyframe before your start, and some players show that frame until the video settles. | Use the exact cut, which starts cleanly on your frame. |
| I need to cut something out of the middle | This tool keeps one continuous stretch. | Trim each part you want to keep, then put them back together with Join clips. |
Privacy: your file stays on your computer
Trimming reads your whole recording to find the part you keep. It all happens in your browser — the untrimmed original never leaves your device.
- What your browser downloads
- The page — and, the first time you use a video tool, the video engine: about 32 MB, then kept in your browser's cache.
- What it sends to us
- Nothing. There is no upload step, no copy on our servers and no account. The work happens in your computer's memory.
- How we know
- Our automated tests run every tool while recording every network request the page makes. A single upload fails the test.
- Where the result lives
- In this browser only, until you press Delete. A finished file is still here if you close the tab and come back; a job still running stops when the tab closes.
Questions
Can I cut a piece out of the middle?
Not with this tool — it keeps one continuous stretch. Trim the parts you want, then join them with Join clips.
Why did my fast cut start earlier than I asked?
A copy-only cut has to start on a keyframe, and those are usually a second or two apart. Tick the exact option to land on the frame you chose.
Does trimming reduce quality?
The fast cut does not touch the picture at all. The exact cut re-encodes once, which is invisible at these settings.
How long should a short be?
Fifteen seconds for one idea; thirty is where most land; forty-five to sixty only when there is genuinely more to show. Longer gives people more places to leave.
Is my video uploaded?
No. The trim happens in your browser and the file never leaves your device.
A tool makes a file fit. It does not make people watch to the end — that is the hook, the order of the shots, the captions and the music. See how Ruzz does it.
Other free tools
Compress video
Too big to upload, email or text? Make it small enough, without it looking bad. Takes a few minutes.
Convert format
Will not play or upload? Turn an iPhone MOV/HEVC, WebM or MKV into an MP4. Often seconds, with no quality loss.
Crop to 9:16
Turn a landscape or square video into a vertical short for Reels, TikTok and Shorts.
Extract audio
Pull the sound out of a video as MP3, WAV or AAC.
Grab a cover frame
Pick any moment and save it as a vertical cover image.
Join clips
Filmed it in three takes? Put them end to end in one video — different shapes and silent clips are fine.
Video to GIF
Turn a moment into a GIF with real colours, not the grainy web palette.
Compress image
Shrink and resize a photo to JPG, WebP or PNG. Instant.
Change speed
Slow motion or sped up, from 0.5× to 2×, with voices at their own pitch.
Remove sound
Take the audio off a video in seconds, picture untouched — then add a trending sound in the app.
Resize video
Exactly 1080×1920, 1080×1350, 1080×1080 or 1920×1080 — the size each platform asks for.