Bitrate Calculator
Calculate the video bitrate needed to hit a target file size, or the file size a given bitrate will produce - built for sizing video exports to a duration and a size limit.
Recommended Settings
Pro Tips
- •Video bitrate and file size trade off directly against duration - doubling the length of a video halves the bitrate you can use for the same file size
- •A 128 kbps audio track is a common default, but reserve more (192-320 kbps) for music-heavy content where audio quality matters more
- •Video hosting sites and messaging apps often cap upload size (Discord's 25 MB non-Nitro limit is a common target) - use Find Bitrate to hit that exact ceiling
- •These are average bitrate figures - most video encoders vary the actual bitrate moment to moment (variable bitrate), so real output size can differ slightly from the estimate
Most Popular
Most people use Find Bitrate to fit a video under a platform's upload size limit
When to Use This Tool
Find the bitrate needed to keep a video export under a specific size, like an upload or attachment limit.
Decide what bitrate to set in your video editor or encoder before exporting.
Predict how much disk space a screen recording or camera capture will use at a given bitrate and length.
See how much file size a bitrate change actually costs before committing to an export.
How It Works
Choose whether you're solving for bitrate or file size
Enter the known values - target size or bitrate, plus the video's duration in hours, minutes, and seconds
Optionally reserve a separate audio bitrate, which is subtracted from (or added to) the video bitrate
The result is calculated using bitrate x duration = file size, converted to a readable unit
100% Private
Files never leave your device. All processing happens locally in your browser.
Lightning Fast
Powered by Client-side JavaScript arithmetic for optimal performance on modern browsers.
Open Source
Built with verified, open-source libraries. Fully transparent.
Frequently Asked Questions
How do I calculate the bitrate needed for a target file size?
Divide the target file size (in bits) by the video's duration in seconds. This tool does that conversion automatically, and can subtract a reserved audio bitrate from the total.
What bitrate should I use for a 10-minute video under 100 MB?
Enter 100 MB and 10:00 into the Find Bitrate tab - with a default 128 kbps audio reservation, that works out to roughly 1.2 Mbps of video bitrate.
Why is my exported file bigger or smaller than this tool predicted?
Most encoders use variable bitrate by default, which adjusts the bitrate moment to moment based on scene complexity - the average usually lands close to the target, but individual exports can vary slightly.
Should I include audio bitrate separately?
Yes, if you want an accurate total - audio typically adds 128-320 kbps on top of the video bitrate, which matters more for shorter clips where audio is a larger share of the total file size.
Is my data sent to a server?
No. All calculations happen locally in your browser using JavaScript - nothing is transmitted anywhere.