A 50MB cap shows up on email, application forms, course sites, and file-transfer pages. There is no field on the converter where you type "50MB". File size follows bitrate and length:
megabytes ≈ (video bitrate in kbps + audio bitrate in kbps) × seconds ÷ 8000
That number is an estimate. The encoder can finish a little over or under the bitrate you set, so aim near 40MB and check the real file. If it is over 50MB, choose the next lower video bitrate and convert again from the original.
The free web converter accepts source files up to 200MB. A file larger than that has to be reduced somewhere else before these steps will run.
Bitrate to try
Use MP4, codec H.264(AVC), and set both bitrates. "k" on the menu is kbps. 5000k means about 5 Mbps.
- 30 seconds: video 10000k, audio 128k → about 38MB
- 1 minute: video 5000k, audio 128k → about 38MB. 6000k is about 46MB if you want to sit closer to the cap.
- 90 seconds: video 4000k, audio 128k → about 46MB. If the file lands over 50MB, use 2000k (about 24MB).
- 2 minutes: video 2000k, audio 128k → about 32MB. 4000k for two minutes is about 62MB, which misses a 50MB cap.
- 3 minutes: video 1024k, audio 128k → about 26MB. 2000k with 96k audio is about 47MB, so convert once and look at the size before you rely on it.
- 5 minutes: video 1024k, audio 96k → about 42MB
- 10 minutes: video 512k, audio 64k → about 43MB
- 15 minutes: video 256k, audio 64k → about 36MB, and the picture will be soft
- 30 minutes: video 128k, audio 64k → about 43MB, which is too little data for a normal picture
There is no 3000k step. When the table jumps from 4000k to 2000k, 2000k is the one that stays under 50MB.
Match the resolution to the bitrate
A high resolution at a very low bitrate looks worse than a smaller frame at the same bitrate.
- 2000k and above: 1920x1080 or 1280x720
- 1024k: 1280x720
- 768k and below: 640x480
Set Scale mode to Fit (keep aspect) when you change resolution. A vertical clip should use a vertical size, such as 1080x1920 or 720x1280, instead of a widescreen frame.
For clips of 15 minutes or more, 50MB is a hard budget. Shorten the video in the app that created it, then compress the shorter file. This site does not trim video.
Compress toward 50MB on Ahelpers
- Check the length of the video and pick a row from the list above.
- Open ahelpers.com or the MP4 converter.
- Select the file. It needs to be 200MB or smaller.
- Set Target format to MP4.
- Set Video options to Customize parameters.
- Set Video codec to H.264(AVC).
- Set Resolution and Fit (keep aspect) if the row calls for a smaller frame.
- Set Video bitrate and Audio bitrate to the row you picked.
- Choose Start conversion and read the output size before you upload it anywhere.
If the result is under 50MB and looks too soft, move up one video bitrate step and export from the original again, as long as the new estimate still fits. If it is over 50MB, move down one step.
Background on bitrate and resolution is in How to compress a video online for free. If the file is an MP4 and you only need it smaller, with no fixed cap, use Compress an MP4 video to a smaller size.
FAQ
Can the converter target 50MB exactly?
No. You set a bitrate, and the size comes out of bitrate times length. Check the file after conversion.
Why did I get 60MB when the table said 46MB?
The clip may be longer than the row you used, or the encoder ran a bit hot. Note the real length, pick that row, or take one bitrate step down and convert from the original.
What about a 25MB email limit?
Use about half the video bitrate in the matching row, then check the file. One minute at 2000k plus 128k audio is about 16MB. Five minutes at 512k plus 64k audio is about 22MB.