Formats · 2026-07-28 · 5 min read
MP4 vs MP3: which format should you download?
Video or audio only? A practical comparison of size, quality and device support.
Updated
What each format actually stores
MP4 is a container: it carries a video stream and an audio stream together, which is why it plays everywhere from a phone gallery to a smart TV. MP3 stores audio only, so the file is a fraction of the size.
If you plan to watch the media, download MP4. If you only need the sound — a podcast, a lecture, a track — MP3 saves both storage and bandwidth.
Size at a glance
| Content | MP4 1080p | MP3 192 kbps |
|---|---|---|
| 5-minute clip | ~100–200 MB | ~7 MB |
| 45-minute talk | ~900 MB–1.8 GB | ~62 MB |
| 3-hour recording | ~3.5–7 GB | ~250 MB |
Quality in practice
For video, quality is set by resolution and bitrate: 1080p is the sweet spot for most screens, 4K only helps on large displays and multiplies the file size.
For audio, 320 kbps MP3 is transparent for almost every listener. 192 kbps halves the size with very little audible difference on phone speakers or earbuds.
Real use cases
- A recorded webinar you presented: MP4, so slides remain visible.
- A three-hour interview you conducted: MP3, because only the voices matter.
- Footage you plan to edit: the highest MP4 available, since re-encoding compounds losses.
Choosing quickly
Watching later, offline, on a big screen: MP4 1080p. Listening on the move: MP3 192 or 320 kbps. Archiving something irreplaceable: the highest MP4 the source offers.
DOWNBOX shows every available option with its estimated size before you commit, so the trade-off is visible up front.
Frequently asked questions
- Does converting to MP3 lose quality?
- Yes, slightly: MP3 is lossy and the audio is re-encoded. At 256 or 320 kbps the loss is inaudible to most listeners.
- Can I turn an MP3 back into a video?
- No. The video stream is discarded when you extract audio, so keep the MP4 if you may need the picture later.
- Which format do older devices handle best?
- Both are extremely well supported. MP3 has the widest compatibility of any audio format, including car stereos and older players.