Convert between video bitrate, file size and duration for H.264, H.265, AV1 and ProRes at any resolution and FPS. Recommended-bitrate matrix for upload and archive.
Built and maintained by Paul Clark, Redmoon Software · Checked against what this tool computes on
| Codec | Bitrate (Mbps) | File size | Fits on |
|---|
File size = (video bitrate + audio bitrate) × duration / 8, in bytes. Recommended bitrates follow YouTube and broadcast guidelines for H.264/H.265/AV1; ProRes uses Apple's published data-rate table. 60 fps gets a ~1.5× multiplier, 120 fps ~2×.
ProRes is an intra-frame intermediate codec — much larger than delivery codecs but ideal for editing.
File size = (video bitrate + audio bitrate) x duration / 8. The recommended bitrate itself is a lookup rather than a formula: each codec carries a table of Mbps per resolution. H.264 is 8 Mbps at 1080p and 45 at 4K UHD, H.265 is 5 and 25, AV1 is 4 and 20, ProRes 422 is 147 and 492. Frame rate then applies a multiplier, 1.0 up to 30 fps, 1.5 at 60 fps and 2.0 at 120 fps.
Resolution and codec move the number furthest. Duration accepts mm:ss, hh:mm:ss or plain seconds and starts at 10:00; Resolution spans 480p to 8K UHD with 1080p selected; Codec defaults to H.264 (AVC). Audio bitrate defaults to 192 kbps and is added to the video rate before the size is worked out, which is why the headline Mbps and the total underneath differ. All five codecs appear in the table simultaneously for comparison.
These are published-guideline starting points, not encoder output. Real file size depends on how much motion and fine detail a shot contains, whether you encode at constant or variable bitrate, and which preset and quality target you choose, so a static talking head at 1080p H.265 will land well under 5 Mbps. The ProRes rows are fixed data rates and therefore dependable; the H.264, H.265 and AV1 rows are estimates that any two-pass encode will beat or miss.
The tool applies a 1.5x frame-rate multiplier above 30 fps, so H.264 rises from 8 to 12 Mbps at 1080p60, H.265 from 5 to 7.5 Mbps and AV1 from 4 to 6 Mbps. At 120 fps the multiplier becomes 2.0 instead.
In the built-in table H.265 sits at roughly 60% of the H.264 rate and AV1 at about half. At 4K UHD that reads 45 Mbps for H.264, 25 Mbps for H.265 and 20 Mbps for AV1, for a comparable picture.
ProRes is an intra-frame editing codec: every frame is compressed independently, with no reference to neighbouring frames. At 1080p the tool lists ProRes 422 at 147 Mbps and ProRes 4444 at 220 Mbps, against 8 Mbps for H.264 delivery.
Yes. The audio figure in kbps is divided by 1,000 and added to the video bitrate before duration is applied. The big number shows video only, while the line beneath it reports the combined video-plus-audio rate actually used for the size.
Type 2:00:00, or 120:00 for minutes and seconds, or 7200 for raw seconds. The duration parser handles all three: two colons are read as hours, minutes and seconds, one colon as minutes and seconds, and a bare number as seconds.
Required bitrate rises with pixel count and with frame rate, so 4K60 needs far more than 1080p24 for comparable quality. Codec generation matters as much: HEVC and AV1 achieve similar quality to H.264 at roughly half to two-thirds the bitrate, at the cost of much heavier encoding and narrower playback support.
The 24 fps default reflects cinematic delivery; broadcast and web content commonly run 30 or 60.
Bitrate requirements depend on how much changes between frames. A static interview shot compresses to a fraction of what a handheld shot of moving foliage needs, and film grain or heavy noise is expensive to encode because it looks like detail that changes every frame.
That is the argument for variable bitrate, which spends bits where the content needs them and saves them elsewhere. Constant bitrate exists for streaming, where a predictable data rate matters more than optimal allocation.
For archival masters the calculation is different again: use a high bitrate or a lossless codec, because every subsequent re-encode compounds the loss from the last one.
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