Video file size calculator
Estimate video export size from average bitrate and duration, or find a video bitrate budget for a file-size limit. Include audio and an optional overhead allowance. Free, browser-based and no file upload required.
Export size settings
Estimate onlyHow to estimate video file size
- Choose “Estimate file size” and enter the full duration, including any intro or outro.
- Enter the average video bitrate from your encoder settings. Choose Mbps or kbps carefully.
- Add the combined bitrate of every audio track, or use 0 for a video without audio.
- Set an optional overhead allowance, then read the estimate in decimal and binary units.
The calculator updates as you type. For example, 10 minutes at 8 Mbps video plus 192 kbps audio contains approximately 614.4 MB of payload. Adding the default 2% allowance gives 626.688 MB. This is a planning estimate rather than an inspection of an encoded file.
Video file size formula: bitrate × duration
Payload bytes = (video bits/s + audio bits/s) × duration seconds ÷ 8Estimated bytes = payload bytes × (1 + allowance percent ÷ 100)One byte contains eight bits. In this tool, 1 Mbps means 1,000,000 bits per second and 1 kbps means 1,000 bits per second. When using Mbps and seconds, a convenient shortcut is payload MB = combined Mbps × seconds ÷ 8.
For the default example: (8 + 0.192) × 600 ÷ 8 = 614.4 MB. Of that, video accounts for 600 MB and audio for 14.4 MB. The 2% allowance adds 12.288 MB. If an overall bitrate reported by a media inspector already includes audio and container data, do not add those components again.
Calculate video bitrate for a target file size
Choose “Bitrate for a size limit,” enter the target in MB, GB, MiB or GiB, and keep duration, audio bitrate and allowance set to the planned export. The calculator works backward to find the available average video bitrate.
Video bits/s = target bytes × 8 ÷ seconds ÷ (1 + allowance / 100) − audio bits/sFor a 100 MB limit and 10-minute duration, with 192 kbps audio and a 2% allowance, the mathematical video budget is about 1115.190 kbps. The tool suggests 1115 kbps, rounded down to whole kbps. The estimated total at that setting is 99.9855 MB. The unused space after rounding is not a guarantee against encoder overshoot.
If audio and allowance leave less than 1 kbps for video, the tool reports that the settings cannot fit instead of showing a negative bitrate. Increase the limit, shorten the clip or reduce the audio bitrate. For a strict cap, leave additional room and verify the exported file. A bitrate-targeted or two-pass workflow can help with size planning, but encoder behavior still matters; a CRF or constant-quality number alone is not a predictable bitrate.
MB vs MiB, GB vs GiB, and Mbps vs MB/s
| Unit | Meaning | Value |
|---|---|---|
| MB | Megabyte | 1,000,000 bytes |
| MiB | Mebibyte | 1,048,576 bytes |
| GB | Gigabyte | 1,000,000,000 bytes |
| GiB | Gibibyte | 1,073,741,824 bytes |
| Mbps | Megabits per second | 1,000,000 bits/s |
| MB/s | Megabytes per second | 8 Mbps |
A 100 MiB allowance is 104.8576 MB, so the two labels are not interchangeable. The same file may appear to have different numeric sizes across applications using different units. This tool shows both systems rather than silently treating MB as a binary unit. See the NIST reference for binary prefixes.
Example video sizes at different bitrates
| Video bitrate | 1 minute | 10 minutes | 1 hour |
|---|---|---|---|
| 2 Mbps | 15 MB | 150 MB | 900 MB |
| 5 Mbps | 37.5 MB | 375 MB | 2.25 GB |
| 8 Mbps | 60 MB | 600 MB | 3.6 GB |
| 20 Mbps | 150 MB | 1.5 GB | 9 GB |
| 50 Mbps | 375 MB | 3.75 GB | 22.5 GB |
At a fixed average bitrate, doubling duration doubles payload size. Doubling bitrate at the same duration does the same. Add audio and allowance for a more complete estimate, especially when the video bitrate is low or multiple audio tracks are included.
Why resolution and codec do not predict file size alone
A 1080p or 4K label describes frame dimensions, not how much compressed data is stored per second. A detailed moving scene, an interview and a static slide can need different bitrates to reach similar visual quality. Frame rate, noise, bit depth, codec, encoder settings and the content all influence that choice.
H.264, HEVC and AV1 can produce different quality at the same bitrate, but at the same actual average video bitrate and duration their video payload sizes follow the same formula. MP4 and MOV are containers, not fixed compression ratios. This calculator therefore asks for bitrate rather than guessing a universal size from resolution or codec.
CBR, VBR and constant quality
For constant bitrate, use the planned video rate. For variable bitrate, use the expected or measured average, not the maximum rate. A quality-targeted export may vary substantially with scene complexity, so a short test encode is often more useful than a size prediction from a quality slider. Adobe's export settings reference explains bitrate settings in an editing workflow.
Plan an export without sacrificing the wrong thing
Start with the required delivery dimensions and frame shape, then choose a bitrate budget. Lower bitrate may reduce file size, but it can also introduce artifacts. If the budget is too small for the image complexity, consider a shorter duration, a lower delivery resolution or a more efficient codec supported by the destination.
Use the video aspect ratio calculator to choose proportional dimensions. If a new shape requires reframing, compare crop loss with a letterbox fit. Confirm non-square-pixel interpretation using the pixel aspect ratio calculator before choosing a final raster. None of these geometric changes alone guarantees a particular compressed size.
Video file size FAQ
How large is a 10-minute video at 8 Mbps?
Video alone is 600 MB in decimal units. With 192 kbps audio, the payload is 614.4 MB. With the calculator's default 2% allowance, the estimate is 626.688 MB.
How much space does one hour of 1080p or 4K video use?
There is no single answer from resolution alone. One hour at 8 Mbps is 3.6 GB of video payload; at 50 Mbps it is 22.5 GB. Add audio and overhead. Use the actual recording or export bitrate for your format.
Does this tool compress a video to 100 MB?
No. It calculates an average bitrate budget for a chosen limit without accessing a file. Apply the settings in an encoder and check the result; actual size and visual quality are not guaranteed.
Does 192 kbps stereo audio count twice?
Usually no: an encoded stereo track labeled 192 kbps is normally 192 kbps total. Add separate tracks if you are exporting more than one. For example, two separate 192 kbps tracks require 384 kbps here.
Why is my exported file larger or smaller than the estimate?
The actual average bitrate may differ from the target. Container structure, metadata, subtitles, extra streams and duration differences can also change size. The allowance is a user-selected estimate, not a measurement of those items.
Can I use this for uncompressed video?
Only if you already know the full video data rate. This calculator does not derive an uncompressed rate from resolution, frame rate, bit depth and chroma sampling. It is primarily intended for bitrate-based recording and export planning.