Send a file that is too big, in parts

When you need this

A 90MB video needs to go to somebody and email stops at 25MB. WhatsApp refuses a large document. The internet is slow enough that one big upload fails halfway and starts again. Splitting the file into pieces means each piece goes on its own, and a failed piece costs you one piece rather than the whole evening.

How to use it

1. Drop the file in and choose a piece size that fits what you are sending through. Around 20MB suits most email.
2. Save the pieces and send them — all at once or over a few messages.
3. Tell the person receiving them to come to this same page and use the joining side. They add all the pieces and get the original file back.

What it does and does not do

• The joined file is identical to the original. Nothing is re-encoded or compressed, so a video loses no quality.
• Every piece is needed. Miss one and the file cannot be rebuilt. There is no repair.
• The person at the other end needs this page, not a special program. It costs them nothing and installs nothing.
• It works on any file type — video, archives, disk images, anything.

Before you split

Ask whether the file needs to be that big. A video is usually the culprit, and if only the sound matters, get the audio out of a video turns 300MB into 30MB and removes the problem entirely. A heavy PDF usually shrinks with make my PDF smaller.

If something goes wrong

• Joining fails. A piece is missing or one did not download fully. Check every piece arrived and that the sizes match what was sent.
• The pieces will not send. Some services block unfamiliar file types. Put each piece in a ZIP, or use a smaller piece size.
• It is taking a long time. Large files are slow on a phone. Leave the page open and the screen on; switching away can stop the work.