How to calculate video bitrate and file size
- On the Recommended bitrate tab, choose the resolution, the frame rate and the codec. The suggested range appears in Mbps and kbps, with a bar showing where it sits on a 0–70 Mbps scale.
- To estimate a file size, open File size ↔ bitrate, type the duration as hh:mm:ss and check the audio bitrate (128 kbps by default).
- Type a video bitrate in kbps to get the file size in MB, or type a file size to get the highest video bitrate that fits it.
- Enter the bitrate in your editor or encoder’s export settings, usually as a target or average bitrate.
Why use this tool
Export settings for uploads
Premiere Pro and DaVinci Resolve can export at a bitrate you set, and HandBrake does too when you choose average bitrate instead of its default constant quality mode. Pick your resolution, frame rate and codec to get a range that keeps uploads sharp without wasting bandwidth.
Fitting a video under a size limit
Email services, chat apps and course platforms cap file sizes. Enter the limit and the duration, and the calculator gives the highest video bitrate that fits once the audio is counted.
Planning storage for recordings
Work out how much disk a recording session needs before you start. One hour at 10,000 kbps with 128 kbps audio is 4557.60 MB, so a full day of footage at that rate needs a large drive.
Comparing codecs
Switch between H.264, H.265 and AV1 to see how much lower a bitrate the newer codecs suggest for the same resolution, then weigh that against how widely each one plays.
Private by design
Every calculation runs in this browser tab, so results update the moment you change a value. There is nothing to upload, no account to create and nothing to install.
Good to know
Two calculators in one. The Recommended bitrate tab suggests a range for a resolution, a frame rate and a codec. The File size ↔ bitrate tab takes a duration and an audio bitrate, then turns a video bitrate into a file size, or a file size into the video bitrate that fits it.
Where the ranges come from. The base figures are for H.264 video in SDR (standard dynamic range). 24, 25 and 30 fps share one range; 48, 50 and 60 fps use a higher one. The low end of each range is in line with the upload bitrates YouTube recommends for SDR video, such as 8 Mbps for 1080p at 30 fps. The full table is below.
Newer codecs. H.265 (HEVC) and AV1 compress more efficiently than H.264. The calculator scales the H.264 range by 0.6 for H.265 and 0.5 for AV1, rounded to the nearest 100 kbps. These factors are a rule of thumb: real savings depend on the encoder, its settings and the footage.
A starting point, not a rule. Fast motion, grain and noise need the top of the range or more. Screen recordings, talking heads and static shots often look fine below it. HDR video usually needs more than the SDR figures here.
The file size formula. File size = (video bitrate + audio bitrate) × duration ÷ 8. Sizes are decimal: 1 kbps is 1000 bits per second and 1 MB is 1,000,000 bytes. Results are rounded to two decimals, and the bitrate for a size is rounded down to a whole kbps so the file stays under the size. Container overhead is not included, so leave a small margin.
Duration format. Type hh:mm:ss (00:10:00), mm:ss (10:00) or plain seconds (600). The first number has no upper limit, so 75:00 is 75 minutes and 4500 is 4500 seconds. The numbers after it must be below 60: minutes in hh:mm:ss, and seconds.
In — Target file size, duration, audio bitrate
500 MB · 00:10:00 · 128 kbps audioOut — Status line
500 MB in 00:10:00 with 128 kbps audio = 6538 kbps video (6.5 Mbps)| Resolution | Frame rate | H.264 | H.265 (HEVC) | AV1 |
|---|---|---|---|---|
| 720p | 24–30 fps | 5–6.5 Mbps | 3–3.9 Mbps | 2.5–3.3 Mbps |
| 720p | 48–60 fps | 7.5–9.5 Mbps | 4.5–5.7 Mbps | 3.8–4.8 Mbps |
| 1080p | 24–30 fps | 8–10 Mbps | 4.8–6 Mbps | 4–5 Mbps |
| 1080p | 48–60 fps | 12–15 Mbps | 7.2–9 Mbps | 6–7.5 Mbps |
| 1440p | 24–30 fps | 16–20 Mbps | 9.6–12 Mbps | 8–10 Mbps |
| 1440p | 48–60 fps | 24–30 Mbps | 14.4–18 Mbps | 12–15 Mbps |
| 2160p | 24–30 fps | 35–45 Mbps | 21–27 Mbps | 17.5–22.5 Mbps |
| 2160p | 48–60 fps | 53–68 Mbps | 31.8–40.8 Mbps | 26.5–34 Mbps |
Frequently asked questions
What bitrate should I use for 1080p video?
For H.264, the calculator suggests 8–10 Mbps at 24–30 fps and 12–15 Mbps at 48–60 fps. Only the low ends come from YouTube: 8 Mbps and 12 Mbps are its recommended upload bitrates for SDR 1080p video. The upper ends leave headroom for detailed footage. H.265 and AV1 can go lower; the table lists their ranges.
What is the difference between CBR and VBR?
Constant bitrate (CBR) keeps the same bitrate all the way through. Variable bitrate (VBR) spends more bits on complex scenes and fewer on simple ones while aiming for an average. For a file you upload or keep, VBR, ideally two-pass, gives better quality for the same size. CBR is mostly used for live streaming, where the connection needs a steady rate. The file size here assumes the bitrate you enter is the average.
Why do H.265 and AV1 need a lower bitrate?
They compress more efficiently than H.264, so they reach similar quality with fewer bits. The calculator assumes about 60% of the H.264 bitrate for H.265 and 50% for AV1, a common rule of thumb. The trade-offs are compatibility and speed: H.264 plays almost everywhere, H.265 and AV1 need newer hardware or software to play smoothly, and both are slower to encode in software. Hardware encoders on recent graphics cards narrow that gap.
How is the file size calculated?
Add the video and audio bitrates, multiply by the duration in seconds and divide by 8. 8000 kbps video plus 128 kbps audio for 60 seconds is 8128 × 60 ÷ 8 = 60,960 kilobytes, or 60.96 MB. Windows counts a megabyte as 1,048,576 bytes, so it shows the same file as about 58.14 MB.
How do I fit a video under a file size limit?
Open File size ↔ bitrate and enter the duration, the audio bitrate and the limit in MB. The calculator returns the highest whole video bitrate that fits: a 10-minute video with 128 kbps audio fits in 500 MB at 6538 kbps. Encoders do not hit a target exactly, so aim a few percent under the limit.
Does the frame rate change the bitrate?
Yes. More frames per second means more pictures to encode. The calculator uses one range for 24, 25 and 30 fps and a higher one, roughly 1.5 times as much, for 48, 50 and 60 fps.