How to Compress Video Online Without (Visible) Quality Loss

A two-minute phone video can easily be several hundred megabytes, and plenty of email services, messaging apps and upload forms cap attachments at a fraction of that. You need the video smaller, but you don't want it to turn into a blocky smear.

Strictly speaking, you can't compress a video much without any quality loss. Truly lossless video stays huge. What you can do is get rid of data your eyes won't notice. Done right, the result looks the same and is often a third or a quarter of the size. This guide shows the settings that matter and the values to use.

Compress a Video Online in Four Steps

1. Open the video converter and choose MP4 as the output, or use MP4 to MP4 if your file is already an MP4.
2. Add your video (up to 1 GB, no sign-up).
3. Open Settings and adjust one or more of the options below.
4. Convert and download. Your upload is deleted automatically afterwards.

The Four Settings That Shrink Video Most

1. Resolution: the biggest win

Halving the width and height cuts the number of pixels to a quarter. On phones and laptops, the difference between 4K and 1080p, or 1080p and 720p, is hard to see.

Use the resize preset (720p, 1080p and so on) rather than typing exact numbers, so the aspect ratio stays correct.

2. Quality (CRF): the smart setting

Constant quality (CRF) tells the encoder to keep a consistent visual quality and spend data only where it's needed. A static talking head gets few bits; a fast-moving football match gets many. Lower CRF means higher quality and bigger files.

For H.264:

• 18–20: visually near-identical to the source. Use it for important footage.
• 23: the standard default, with a good balance.
• 26–28: noticeably smaller, still fine for chat and social.

For H.265/HEVC, use values about 4–6 higher for similar quality (28 is a common default).

If you only change one thing, change CRF. It usually beats picking a fixed bitrate.

3. Codec: H.264, H.265 or AV1

• H.264: plays everywhere. Choose it when compatibility matters most.
• H.265 (HEVC): often 25–50% smaller than H.264 at similar quality. Plays on modern phones and Macs, but some Windows PCs and older TVs need an extra codec.
• AV1: smaller still, and supported by modern browsers and newer devices, but encoding is slower and older hardware may not play it.

For a video you'll email to anyone and everyone, stick with H.264 and lower the resolution. For your own archive or modern devices, H.265 saves real space.

4. Frame rate and audio

• Dropping from 60 fps to 30 fps saves data, especially for screen recordings and talking heads. Keep 60 fps for gaming and sports.
• Set audio to 128 kbps AAC. Speech doesn't need more, and music is fine at that rate for most viewers.
• For silent clips, turn on remove audio.

Recommended Recipes

Email or WhatsApp (tight limits): MP4, H.264, 720p, CRF 26, 30 fps, audio 96–128 kbps.

Uploading to a course platform or form: MP4, H.264, 1080p, CRF 23, audio 128 kbps.

Archiving your own footage: MP4, H.265, original resolution, CRF 24–26, audio 160 kbps.

Screen recordings: MP4, H.264, original resolution, CRF 25, 30 fps. Screen content compresses extremely well.

Trim Before You Compress

The cheapest megabyte is the one you never encode. Use the trim start and trim end options to cut dead air at the beginning and end. A 3-minute clip trimmed to 90 seconds is half the size before you change anything else.

Things That Make Files Bigger

• Raising quality above the source. Re-encoding a heavily compressed video at a low CRF adds data without adding detail.
• Converting to GIF. GIFs are enormous compared with MP4. Use MP4 to GIF only for very short loops.
• Old formats. AVI and WMV with legacy codecs are much less efficient than H.264. Converting AVI to MP4 or WMV to MP4 often shrinks them a lot.

Compressing iPhone and Mac Videos

iPhone videos are usually MOV files with HEVC. To make one smaller and playable everywhere, convert MOV to MP4 with H.264 at 1080p and CRF 23. You'll typically end up with a file that's both more compatible and noticeably smaller. More on that in MOV vs MP4.

Summary

To compress video online without visible quality loss:

1. lower the resolution
2. use a sensible CRF instead of a fixed bitrate
3. pick the codec that fits where the video will be played
4. trim what you don't need

Start with the video converter, and if you only need the soundtrack, MP4 to MP3 gives you a tiny audio file instead.