Video Compressor
Lower CRF, scale resolution, or cap bitrate to hit your target size. All processing happens locally in your browser; files never leave your device.
$Drag in a video file, or click to select
Video is processed only in your browser memory
Video is read into browser memory — nothing is uploaded
CRF, resolution, encoding preset and bitrate cap
FFmpeg WASM transcodes and exports locally
Compress Video for Discord, Email & Chat
Local · No uploadsShrink MP4, MOV, MKV, AVI, or WebM videos for Discord, email, WhatsApp, and other upload forms. Lower the CRF, reduce resolution, choose a faster preset, or cap the bitrate to trade quality for size. Compression runs locally in your browser — your files never leave your device.
Quick Answers
- Which CRF: 23 is close to the original (x264's default), 18 is visually lossless, 28 shrinks files noticeably. Try 23–28 for everyday use; screen recordings and archives do best at 16–20 (text is the first thing compression blurs).
- x265 uses a different scale: x265 CRF 28 ≈ x264 CRF 23 — values can't be copied across encoders.
- Three size levers: CRF (quality baseline), resolution (halving it leaves 1/4 the pixels), and preset (slower = smaller at the same quality). To hit an exact size, use the max-bitrate cap instead.
- Compression runs in your browser (x264 via FFmpeg WASM — the exact same encoder as the command line). Free, no watermark, no sign-up, files never uploaded.
How to Reduce Video File Size
- 1
Upload your video file
- 2
Set the CRF: higher values mean smaller files and lower quality
- 3
Optionally adjust the output resolution and max bitrate
- 4
Click Compress, then download the smaller video
Common Uses
- Get files under a platform's size limit for upload
- Free up storage space by shrinking large videos
- Make videos small enough to send over email or chat
Things to Keep in Mind
- Compression is lossy — aggressive settings visibly reduce quality
- Different encoders vary in compression efficiency
- Very large files take a long time and are limited by browser memory
How to Choose a Video Compressor
- vs. desktop tools like HandBrake or Format Factory: nothing to install — open your browser and go
- vs. upload-based tools: your files never leave your device
- Adjustable CRF / resolution / bitrate for precise size-versus-quality control
How Video Compression Works
- CRF (Constant Rate Factor) is the rate-control mode in x264/x265: lower values mean better quality and larger files. 23 is the "visually near-lossless" default, 18 reaches visually lossless, and 28 shrinks files noticeably. It keeps quality consistent frame to frame instead of targeting a fixed file size.
- The alternative is target-bitrate mode (ABR/2-pass): fix the bitrate first and get a predictable file size, at the cost of quality dips on complex scenes. That's the idea behind this tool's "max bitrate" cap — for when you must hit a specific size.
- Resolution and encoding preset are the other two levers: halving the resolution leaves only 1/4 the pixels, and slower presets (slow / veryslow) let the encoder search harder for compression, delivering better quality at the same size. Combining all three is how you reach the best size-to-quality ratio.
- This site runs x264 encoding via FFmpeg WASM in your browser — the exact same encoder as command-line FFmpeg, just running locally on your device with zero uploads.
Video Compression FAQ
Which CRF should I use?
CRF 23 is close to the original quality; 28 shrinks files noticeably; 32 is smallest but visibly degraded. Try a few values between 23 and 28 to find your sweet spot.
How do I compress a video for Discord or email?
Start at 720p, set CRF to 26–28, then enable a bitrate cap if you still need to shrink the file. Discord lists a 20MB limit for free uploads, while many email providers cap attachments near 25MB — check the target app before exporting.
How much quality is lost?
It depends on your CRF and resolution settings. A low CRF at the original resolution loses very little; the harder you compress, the more visible it gets. Start with a mild compression and check the result.
Which output format is used?
MP4 (H.264) — the most compatible option, playable on virtually every device and platform.
How do I compress a video to a specific size?
Combine the "max bitrate" cap with trial and error: set a target bitrate and adjust until the output is close to your goal.
My video is too big to send — what should I do?
Raise the CRF or reduce the resolution here to shrink it dramatically, then send it by email or chat.