How to Compress a Video for WhatsApp, Email or an Upload Limit

To compress a video for WhatsApp, email or an upload form, open Compress Video, choose Target size, type the limit in MB (16 for a chat, 25 for Gmail) and click Compress Video. If the clip is long, cut it down first with Trim Video, because every second you remove leaves more of the size budget for the rest. Both tools run in your browser, so the video is never uploaded.

Why is my video file so big?

A video's size is almost exactly its bitrate multiplied by its length. Phones record at high bitrates so the footage holds up when edited, which is why a two-minute clip can be well over a hundred megabytes.

Three things decide the final size:

• Duration: twice as long means roughly twice as big, at the same quality.
• Bitrate: how many bits are spent on each second of picture and sound.
• Resolution: fewer pixels per frame need fewer bits to look sharp, so 720p can use a much lower bitrate than 1080p before it looks blocky.

Compression works on all three. You trim to cut duration, then lower the bitrate and, if needed, the resolution.

What size should a video be for WhatsApp, email or a form?

Aim a little under the limit of wherever the file is going:

• Chat apps: about 16 MB is a safe size for sending a video in a chat on a slow connection. WhatsApp also lets you send larger files as documents.
• Email: Gmail accepts attachments up to 25 MB. Other mail services can be lower, so check yours.
• Job portals, college and government forms: often 5 MB or 10 MB.

There are ready-made pages with the target already filled in: Compress Video for WhatsApp (16 MB), Compress Video for Email (25 MB), plus 10 MB and 5 MB versions.

How does Target size work? A worked example

The tool shares your target out over the length of the video. It keeps 5% back for the container, reserves 96 kbps for the sound (when Keep audio is ticked), and gives everything else to the picture. One MB here means 1,048,576 bytes.

Take a 2-minute clip with a 16 MB target:

• Total budget: 16 MB × 8 × 0.95 ≈ 127.5 megabits
• Audio: 96 kbps × 120 s ≈ 11.5 megabits
• Video: about 116 megabits ÷ 120 s ≈ 967 kbps

967 kbps is thin for 1080p but comfortable for 720p. Trim the same clip to 1 minute and the video budget jumps to about 2,029 kbps, more than double, because the audio share shrinks too. That's why trimming first matters.

If you'd rather not think in megabytes, the Light, Balanced and Strong presets set the bitrate from the frame size and frame rate. For a 720p video at 30 fps, Balanced works out to about 1.66 Mbps (roughly 13 MB per minute including sound) and Strong to about 0.97 Mbps (roughly 8 MB per minute).

How do I compress a video to a target size?

1. Open Compress Video and drop your file onto the upload area. Its current size and average bitrate in kbps appear under the options.
2. Under Compression, choose Target size and type your limit in Target file size (MB).
3. Set Max resolution. 720p suits most phone screens; choose 480p for long clips or very small targets. The setting applies to the shorter side and never enlarges, so a vertical 1080×1920 clip becomes 720×1280 at 720p.
4. Untick Keep audio if the clip doesn't need sound, such as a silent screen recording. That gives the picture the 96 kbps the audio would have used.
5. Click Compress Video. A progress bar shows how far along it is, with a Cancel button. The file downloads automatically, and you see the before and after sizes with a preview.

The result is an MP4 with H.264 video and AAC audio, which plays on practically every phone and computer. If your browser can't encode H.264 (some Firefox versions can't), the tool saves a WebM with VP9 video instead.

Should I trim the video before compressing?

Yes, whenever there's footage you don't need. Open Trim Video, drag the two handles under the preview, or play to the right moment and click Set start to playhead and Set end to playhead. You can also type times such as 1:15 into Start and End.

By default the video stream is copied without re-encoding, so trimming is quick and loses nothing. Only the first moments near the start point are re-encoded when that's needed. Tick Frame-accurate cut if the cut must land on an exact frame; that re-encodes the whole clip and takes longer. Click Trim Video, then compress the trimmed file.

My video won't play or upload: convert MOV or MKV to MP4

Some portals and older devices reject iPhone MOV files or MKV downloads. MOV to MP4 and MKV to MP4 fix that. With Video codec on Automatic, Quality on High and Resolution on Original, a file that already uses H.264 or HEVC is repackaged without re-encoding: usually a matter of seconds, with no quality loss. Other codecs are re-encoded to H.264.

One catch: iPhones set to High Efficiency record HEVC, and Automatic keeps HEVC inside the new MP4. If an older PC, TV or upload form still refuses the file, pick H.264 under Video codec to force a fully compatible copy.

If you need the file smaller as well as compatible, skip the converter and go straight to Compress Video. Its output is always MP4.

What about vertical or square video?

Resize Video reshapes a clip for a platform. Under Shape, the 9:16, 1:1, 4:5 and 16:9 presets make frames 1080 pixels on the shorter side (1080×1920 for 9:16), and Fit lets you choose Fit (add bars), Fill (crop edges) or Stretch. To make a file smaller, though, the Max resolution setting in Compress Video does the job in one step.

Troubleshooting

• "This file can't be read in the browser": AVI, WMV and FLV aren't supported. MP4, MOV, M4V, WebM, MKV and MPEG-TS are. Export the video as MP4 from the app that made it.
• A message about WebCodecs: the video tools need a recent Chrome or Edge, or Safari 17 or newer. Firefox reads most files but lacks some encoders.
• The result is still over the target: the tool says so after compressing. The target is too small for that length of video, so lower the resolution, turn off audio or trim more.
• "Already very efficiently compressed": the original was lean to begin with. The tool never raises the bitrate above 90% of the original's, so try Strong or a lower resolution.
• A phone stalls on a long 4K clip: phones can run out of memory on big jobs. Use a laptop, or trim first.

Quick answers

How do I compress a video to under 16 MB?

Open Compress Video, choose Target size, enter 16 and click Compress Video. For clips longer than a minute or two, also set Max resolution to 720p or 480p so the picture stays clean at the lower bitrate.

Does compressing a video reduce its quality?

Yes, some. Compression lowers the bitrate, so fine detail softens. Lowering the resolution at the same time usually looks better than squeezing a full-resolution picture into too few bits.

Is my video uploaded when I compress it on EasyConvert?

No. Compress Video decodes and re-encodes the file inside your browser using its built-in WebCodecs encoders, so the video stays on your device.

Can I compress an AVI or WMV file?

Not in the browser. The video tools read MP4, MOV, M4V, WebM, MKV and MPEG-TS, so export the video as MP4 from the app that made it, then compress that.