UtilityKit

500+ fast, free tools. Most run in your browser only; Image & PDF tools upload files to the backend when you run them.

Video Trimmer

Cut and trim MP4, WebM, MOV videos to exact start and end times, right in your browser.

About Video Trimmer

Video Trimmer lets you cut any MP4, WebM or MOV video to an exact start and end time directly in your browser. Powered by ffmpeg.wasm, all processing happens locally — your video file never leaves your device or reaches any server. Just upload your clip, enter the start and end timestamps in HH:MM:SS format, and hit Trim. The tool uses stream-copy mode so trimming is extremely fast and lossless — no re-encoding means no quality loss and near-instant results for most clips. The trimmed video is shown inline for preview before you download it.

Why use Video Trimmer

  • 100% private — your video never leaves your device
  • Lossless stream-copy trim — no re-encoding and no quality loss
  • No file size limits imposed by server quotas
  • Works offline after the initial ffmpeg.wasm load
  • No watermarks, no signup, completely free
  • No file size limits imposed by server quotas or upload caps

How to use Video Trimmer

  1. Click or drag your MP4, WebM or MOV file onto the upload area.
  2. Preview the video in the built-in player to identify the exact segment you need.
  3. Enter the start time and end time in HH:MM:SS format.
  4. The selected duration in seconds is shown automatically.
  5. Click 'Trim Video' and wait for ffmpeg.wasm to process locally.
  6. Preview the trimmed output and click Download.
  7. Enter the start time and end time in HH:MM:SS format (e.g. 00:01:23).

When to use Video Trimmer

  • Cutting a highlight clip from a longer recording
  • Removing silence or unwanted sections from the start or end of a video
  • Preparing a short clip for social media from a longer source
  • Quickly splitting a lecture or webinar recording into segments
  • Cropping a long screen recording down to the relevant demo portion
  • Trimming dashcam or security footage to the moment of interest

Examples

Trim a 5-minute clip out of a 1-hour webinar

Input: 60-min MP4 source, start 00:12:30, end 00:17:30

Output: 5-minute MP4, lossless stream-copy, completes in under 10 seconds

Cut a 15-second highlight from gameplay

Input: 10-min WebM screen capture, start 00:04:22, end 00:04:37

Output: 15-second WebM clip ready to share on Discord or Twitter

Remove a long intro from a tutorial

Input: 20-min MOV recording, start 00:01:45, end 00:20:00

Output: 18-min 15-sec MOV with the intro removed, original quality preserved

Tips

  • Use the inline preview player to scrub to the exact frame before typing your timestamps — it removes the guesswork.
  • If your trim falls between keyframes and you need frame-exact cuts, re-encode in the Video Resize & Converter tool first to insert more keyframes.
  • For very long source files (1 hour+), trim in two passes: a rough cut first, then a tight cut on the smaller intermediate file.
  • Keep your browser tab focused while ffmpeg.wasm is processing — background tabs are throttled and finish slower.
  • After the first run, ffmpeg.wasm is cached in IndexedDB, so subsequent trims start instantly even offline.
  • Use HH:MM:SS for clarity even on short clips — '00:00:42' is less error-prone than '42'.

Frequently Asked Questions

Does my video leave my device?▾
No, processing is 100% local in your browser using ffmpeg.wasm. Your file is never uploaded to any server.
Will trimming reduce video quality?▾
No. The tool uses stream-copy mode which copies the video and audio streams without re-encoding, preserving the original quality exactly.
What video formats are supported?▾
MP4, WebM, and MOV are supported as inputs. The output will be in the same container format as your input.
Why does it say '~30MB on first use'?▾
ffmpeg.wasm downloads the WebAssembly binary (~30MB) on first use. This is cached by your browser so subsequent uses are instant.
Why does it need Chrome or Edge?▾
SharedArrayBuffer — required by ffmpeg.wasm for multi-threading — is only available in browsers that send COOP/COEP headers, which the site configures for Chrome and Edge.
Can I trim to sub-second precision?▾
Yes, just type seconds as decimals in the time field, e.g. 00:01:23 represents 1 minute 23 seconds exactly.

Explore the category

Video Compressor Reduce MP4, WebM and MOV file size with adjustable H.264 CRF compression — runs entirely in your browser. Video Rotator Rotate MP4, WebM and MOV videos 90, 180 or 270 degrees, or flip horizontally / vertically. Video Looper Loop an MP4, WebM or MOV clip a chosen number of times into one continuous output file. Video Merger Concatenate multiple MP4, WebM or MOV clips into one continuous video file — no upload required. Video Cropper Crop a rectangular region out of any MP4, WebM or MOV using a draggable selection rectangle. Video Mute / Audio Remover Strip the audio track from any MP4, WebM or MOV video, lossless and instant.
MP4 and H.264 Explained: How Modern Video Compression Works An MP4 is just a wrapper. The real magic is the codec inside. We unpack containers, codecs, B-frames, and why H.264 is still everywhere desp May 2026 · 9 min GIF vs WebP vs MP4: Which Animation Format Wins on the Web? Animated GIFs are nostalgic but heavy. WebP and MP4 deliver the same motion at a fraction of the size. We compare file size, browser support May 2026 · 9 min

Glossary

ffmpeg.wasm
A WebAssembly port of FFmpeg that runs the full video toolkit inside the browser tab without any server-side processing.
SharedArrayBuffer
A JavaScript memory primitive required for multi-threaded WebAssembly. Browsers gate it behind cross-origin isolation (COOP/COEP) headers.
Stream copy
An FFmpeg mode (-c copy) that muxes existing audio/video streams into a new container without decoding or re-encoding, making it lossless and fast.
Container format
The wrapper file (MP4, WebM, MOV) that packages video, audio and metadata streams together.
Codec
The algorithm that encodes/decodes video (H.264, VP9, AV1) or audio (AAC, Opus). The container holds the codec output.
Keyframe
A self-contained video frame from which playback can start. Stream-copy trims snap to the nearest keyframe at the cut point.
COOP/COEP
Cross-Origin-Opener-Policy and Cross-Origin-Embedder-Policy headers that enable SharedArrayBuffer by isolating the page from cross-origin scripts.
Timestamp
A position in the video expressed as HH:MM:SS or seconds. Used by FFmpeg's -ss (start) and -to (end) flags.