Why 720p is the most-downloaded resolution
Three reasons 720p is what most people actually save:
- File size. A 10-minute 720p MP4 is ~80–150 MB. A 10-minute 1080p MP4 is ~300 MB. 4K is over 1 GB. For phone storage, USB stick transfers, email attachments and chat shares, 720p is the practical sweet spot.
- Bandwidth. Slow Wi-Fi, mobile data, hotel internet — 720p downloads in a fraction of the time of higher resolutions and looks identical on a phone or tablet screen.
- Single-file format. 720p is the highest resolution YouTube serves as a pre-merged stream. That means a 720p download is a single byte-for-byte copy from YouTube, no client-side muxing, no risk of AV-sync issues. The cleanest possible save.
When you should pick something else
Pick a different resolution if:
- Editing footage → pick 1080p or 4K. Editing a re-encoded 720p source costs a generation of quality.
- Watching on a 27"+ monitor → 1080p is visibly sharper. 720p was designed for laptops and small TVs, not desktop monitors.
- Archiving the master → take the highest resolution YouTube has. Storage is cheap, you can always downscale later, you can never upscale.
- Saving audio only → switch to the audio-only tab. 720p video that you never watch is wasted bytes; m4a or MP3 is what you want.
File size estimates at 720p
Rough rule of thumb at 720p H.264 / AAC:
- 3-minute music video — 25–45 MB
- 10-minute tutorial — 80–150 MB
- 30-minute talk — 200–350 MB
- 60-minute podcast — 400–700 MB
- 2-hour livestream replay — 800 MB – 1.4 GB
Compared to 1080p the file is ~3× smaller for near-identical perceived quality on phone-sized screens. Comparing to 4K it is roughly 8× smaller.
Why 720p downloads do not need a muxer
Above 720p YouTube serves video and audio as separate streams that have to be combined client-side. At 720p and below YouTube still publishes a progressive MP4 with both tracks already merged. So 720p is the highest quality you can download with a one-shot fetch — no in-browser mux step, no chance of AV sync drift, smaller memory footprint, faster total time-to-disk.
Most simple YouTube downloaders (the ones that just hand you a single URL) cap at 720p for exactly this reason: higher resolutions need a real pipeline. VidPickr does both — one-shot for 720p / 480p / 360p, real client-side mux for 1080p+.