Undersize
Video compressor for iPhone. Fit WhatsApp, Discord, mail.
Oversize video? Make it Undersize — straight from the share sheet, at exactly the size you need. Fully offline, one payment, no subscription.
Compress without leaving the app you're in
Every other compressor makes you quit WhatsApp, open their app, re-import the video, wait, then go back and start the message again. Undersize adds itself to the iOS share sheet, so you tap Share, tap Undersize, and send. The video never leaves your phone.
Ask for a size and get that size
Tell it 16 MB and you get 16 MB — not 40. Undersize measures the result and encodes a second time if the first pass overshoots, so the file actually fits the limit rather than approximately fitting it.
WhatsApp — 16 MB
Discord — 10 MB
Email — 20 MB, accounting for the ~33% that attachment encoding adds
Custom — any size in MB, or a percentage of the original
Nothing is uploaded, ever
Compression runs on your device using Apple's media frameworks. There is no server, no account, no analytics and no ads. Undersize also strips the GPS coordinates most phones embed in video files, so sharing a clip doesn't disclose where it was filmed.
One payment
Free covers 2 videos a day. Pro is a single purchase — not a subscription — and unlocks unlimited compressions plus batch mode for several videos at once. Buy it once, keep it.