Video File Size Calculator
Estimate video file size from bitrate and length, find the bitrate that fits a size limit, or see how many minutes of footage fit on a memory card or drive.
The interactive tool loads here when JavaScript runs.
About this toolWhat is the Video File Size Calculator?
Video file size is simple maths once you know the bitrate, and this calculator does it in three directions. Enter a video and audio bitrate and a duration to get the file size in MB and GB. Enter a size limit and a duration to get the video bitrate that fits. Or enter a card or drive capacity to see how many minutes of recording it holds.
Presets cover YouTube's recommended upload bitrates and Apple ProRes data rates, so you can plan storage for a shoot, check whether an export will go under an upload limit, or set the right number in an encoder. A container overhead setting and a multi-camera multiplier make the estimate match real files more closely.
- File size from video and audio bitrate and duration
- Video bitrate needed for a target size
- Recording time for a card or drive
- YouTube and Apple ProRes bitrate presets
- Decimal and binary units, overhead and multi-stream options
- Size table from one minute to two hours
How to use the Video File Size Calculator
- Choose what you want to know: file size, bitrate for a size limit, or recording time on a card.
- Pick a preset bitrate or type the video bitrate from your camera spec or encoder settings, in Mbps or kbps.
- Enter the audio bitrate (0 for none) and the duration as seconds, m:ss, h:mm:ss or 1h30m.
- For a size limit, enter the target in MB or GB; for recording time, enter the card capacity as printed on it.
- Adjust overhead and the number of cameras or streams if needed, and read the result and the per-minute table.
Worked examples
1080p upload at YouTube's recommended rate
Input
8 Mbps video, 192 kbps audio, 10 minutes, 0% overhead
Output
614.4 MB, 3.69 GB per hour
(8 + 0.192) Mbps × 600 s ÷ 8 = 614.4 MB.
Fitting a clip into 25 MB
Input
25 MB target, 60 s, 128 kbps audio, 0% overhead
Output
3.205 Mbps video (3,205 kbps)
25 MB is 200 megabits; over 60 s that is 3.33 Mbps in total, minus 0.128 for audio. Aim a few percent lower in practice.
Card space for a shoot
Input
128 GB card, 100 Mbps, no audio, 0% overhead
Output
2 h 50 min (10,240 s)
128 × 10⁹ × 8 ÷ 10⁸ bits per second. The formatted card holds slightly less.
Background and insight
Bitrate is the amount of data per second of video. Size is bitrate times time, divided by eight to turn bits into bytes: 8 Mbps for 10 minutes is 8,000,000 × 600 ÷ 8 = 600 MB, and with 192 kbps audio added it is 614.4 MB. Camera makers, card makers and video software count in decimal units, where 1 Mbps is 10⁶ bits per second and 1 GB is 10⁹ bytes. Windows reports sizes in binary units (GiB, 1,073,741,824 bytes) but labels them GB, which is why a 128 GB card shows about 119 GB.
The presets use published figures. YouTube Help recommends, for SDR uploads, 8 Mbps for 1080p at 24 to 30 fps and 12 Mbps at 48 to 60 fps, 16 and 24 Mbps for 1440p, and 35 to 45 Mbps and 53 to 68 Mbps for 4K. Apple's ProRes white paper gives target data rates at 1920 × 1080 and 29.97 fps of about 45 Mbps for ProRes 422 Proxy, 102 Mbps for LT, 147 Mbps for 422, 220 Mbps for 422 HQ and 330 Mbps for 4444. ProRes rates scale roughly with pixel count and frame rate.
Most delivery codecs use variable bitrate, so a file's size reflects its average rate. Containers such as MP4 and MOV add indexes and headers, typically well under one percent, and the tool lets you add a percentage for that. The reverse calculation subtracts audio and overhead from the total budget, which is how two-pass encoders hit a target size.
Common use cases
Planning storage for a shoot
Work out how many cards or how much SSD space a day of recording needs.
Hitting an upload or attachment limit
Find the bitrate to set in an encoder so a clip lands under the cap.
Choosing a codec for editing
Compare the hourly size of ProRes, high-bitrate H.264 and delivery files.
Streaming and podcast archives
Estimate monthly storage for recorded streams, meetings or multi-camera shows.
Tips and limitations
- Camera bitrates are maximums or averages; real files at the same setting vary with scene detail and motion.
- For a hard size limit use two-pass encoding and aim 3 to 5% under the cap.
- Uncompressed 48 kHz 16-bit stereo audio is 1,536 kbps, far more than AAC at 128 to 320 kbps.
- Megabits (Mb) and megabytes (MB) differ by a factor of eight; bitrates are always bits.
- High frame rates and 10-bit codecs need more bitrate for the same quality, so scale presets up rather than reusing a 1080p30 figure.
Frequently asked questions
How do I calculate video file size from bitrate?
Multiply the total bitrate in bits per second by the duration in seconds and divide by 8 for bytes. 10 Mbps for 60 s is 75 MB.
How many GB is an hour of 4K video?
It depends on the bitrate: at 45 Mbps about 20 GB, at 100 Mbps 45 GB, and at 400 Mbps 180 GB.
What bitrate should I use to fit a video under a size limit?
Divide the limit in bits by the duration, subtract the audio bitrate, and leave a few percent for overhead. The bitrate mode does this and shows the kbps value to type into an encoder.
Why does my 128 GB card show less space?
Card makers use decimal gigabytes (10⁹ bytes) while Windows and some cameras show binary gibibytes (2³⁰ bytes), and the file system takes a little space.
How big is ProRes 422 HQ per hour?
At Apple's target of 220 Mbps for 1080p at 29.97 fps, about 99 GB per hour of video. 4K and higher frame rates need proportionally more.
Does resolution change file size if the bitrate is fixed?
No. At a fixed bitrate the file size depends only on time; a higher resolution at the same bitrate simply gets fewer bits per pixel and lower quality.
Is there an in-depth guide to the Video File Size Calculator?
Yes. “Video Bitrate and File Size: The Simple Maths Behind Storage” covers the background, how it works, common pitfalls and worked examples. Read the full guide.
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