Video Bitrate Calculator & File Size Calculator
This video bitrate calculator works both ways: enter a size limit and duration to get the bitrate that fits, or a bitrate and duration to see how big the file will be. Platform limits such as Discord (20 MB), WhatsApp (16 MB) and Gmail (25 MB) are one click away, and the result suggests a resolution and opens the compressor with that target.
- Runs on your device
- Browser APIs
- Works offline
Updated
How to calculate video bitrate for a file size
Step 1: Choose what to calculate: Bitrate, File size or Duration.
Step 2: Pick a platform under Size limit or type a Custom size, and enter the duration in hours, minutes and seconds.
Step 3: Set the audio bitrate (or none), then read the result, the suggested resolution and the “Fits on” list.
Step 4: Click Compress to … to open the video compressor with that exact target, or copy the summary.
Good to know
Formats
Nothing to upload — everything starts from this page and is saved to your device.
How it runs
- Built-in browser features
- Uses standard browser features only — nothing extra to download.
| Platform | Plan / type | Limit |
|---|---|---|
| Discord | Free | 20 MB |
| Discord | Nitro Basic | 50 MB |
| Discord | Nitro | 500 MB |
| Photo / video message | 16 MB | |
| Sent as a document | 2 GB | |
| Gmail | Attachment | 25 MB |
| Yahoo Mail | Attachment | 25 MB |
| Outlook.com | Attachment | 20 MB |
| iCloud Mail | Attachment | 20 MB |
| Telegram | Free | 2 GB |
| Telegram | Premium | 4 GB |
| X / Twitter | Video | 512 MB |
Checked 11 October 2026. Platforms change their limits — check the official help pages if a number looks different.
What bitrate fits common upload limits
Short clips can use a high bitrate; long ones must share the same megabytes across more seconds. These are the video bitrates the calculator returns with 128 kbps audio, already 4% under each limit so the upload never bounces.
| Size limit | 30 s | 1 min | 3 min | 10 min |
|---|---|---|---|---|
| WhatsApp · 16 MB | 4.12 Mbps | 2.00 Mbps | 581 kbps | 85 kbps |
| Discord free · 20 MB | 5.19 Mbps | 2.53 Mbps | 758 kbps | 138 kbps |
| Gmail · 25 MB | 6.52 Mbps | 3.19 Mbps | 979 kbps | 204 kbps |
| Discord Nitro Basic · 50 MB | 13.2 Mbps | 6.52 Mbps | 2.09 Mbps | 536 kbps |
How to calculate video file size
File size = (video bitrate + audio bitrate) × duration. Bitrates are in kilobits per second, so divide by 8 to get bytes: a 5,000 kbps video with 128 kbps audio is 641 kilobytes every second, and a minute is about 38.5 million bytes, which apps show as 36.7 MB. The container adds roughly 1% on top.
To calculate video bitrate for a limit, run it backwards: size × 8 ÷ seconds, minus the audio. That is exactly what the Bitrate mode does, then it takes 4% off as a safety margin.
How big is a video file? 1 minute to 2 hours
Yes, bitrate decides file size: double the bitrate and the file doubles. These are the sizes at the typical H.264 bitrate the calculator suggests for each resolution:
| Video | 1 min | 10 min | 1 hour | 2 hours |
|---|---|---|---|---|
| 720p at 4.00 Mbps | 29.8 MB | 298 MB | 1.75 GB | 3.49 GB |
| 1080p at 8.00 Mbps | 58.7 MB | 587 MB | 3.44 GB | 6.88 GB |
| 4K (2160p) at 40.0 Mbps | 290 MB | 2.83 GB | 16.99 GB | 33.97 GB |
What is a good bitrate for 1080p?
For H.264 at 30 fps, 8 Mbps looks good and about 4.5 Mbps is the lowest that stays comfortable; below that, a smaller resolution looks sharper than a starved 1080p picture. Fast motion and 60 fps need more: YouTube’s upload guidelines recommend 12 Mbps for 1080p at 60 fps.
| Resolution | Lowest comfortable | Typical good |
|---|---|---|
| 4K (2160p) | 20.0 Mbps | 40.0 Mbps |
| 1440p | 10.0 Mbps | 16.0 Mbps |
| 1080p | 4.50 Mbps | 8.00 Mbps |
| 720p | 2.20 Mbps | 4.00 Mbps |
| 480p | 900 kbps | 1.50 Mbps |
| 360p | 450 kbps | 800 kbps |
Tips & troubleshooting
Planning a Discord upload? The compress video for Discord page already knows the limits.
Not sure what bitrate your file has now? Media info online shows the overall and per-track bitrate.
Below about 150 kbps of video the picture falls apart; shorten the clip or allow a bigger file instead.
Turning audio off frees its bitrate for the picture; worth it for screen recordings without narration.
Video File Size & Bitrate Calculator FAQ
How do I calculate video bitrate?
Bitrate (kbps) = file size in kilobits ÷ seconds. For a 20 MB limit and a 60-second clip, that is 2.77 Mbps in total; subtract the audio and keep a small margin. Choose Bitrate here and the calculator does all of it.
How do I convert Mbps to MB?
Divide by 8 for megabytes per second, then multiply by the duration. 8 Mbps is 1 MB per second, so a minute is about 60 MB. Use File size mode to include audio and container overhead.
Why is my exported file a bit different from the estimate?
Encoders vary the bitrate from scene to scene and containers add a little overhead. ProMedia’s video compressor aims about 4% under a target to stay safe, so files usually land slightly below the limit.
Does this calculator also work for streaming?
The maths is the same: the bitrate you stream at must stay below your upload speed, with headroom. It does not test your connection, though; it only converts between bitrate, size and time.