Multiply your total bitrate (video + audio, in Mbps) by the duration in seconds, then divide by 8. For example: 8 Mbps video + 0.128 Mbps audio ร 150 seconds รท 8 = approximately 153 MB. This calculator does that automatically and adds a small overhead correction for real-world containers.
Free Online Tool
Video Bitrate &
File Size Calculator
Instantly estimate how large your video will be, or what bitrate you need to hit a target size. Built for screen recordings, product demos, and short-form uploads.
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Most compatible. Widely supported across all platforms and devices.
h
min
sec
2 min 30 sec total
Mbps
Screen recordings: 6-12 Mbps ยท Twitter/X: 4-5 Mbps
Estimated File Size
43.9
MB
8 Mbps video + 128 kbps audio ยท 2m 30s
Total bitrate
8.13 Mbps
Per minute
61 MB/min
Pixels/frame
2.07M
Practical examples at current settings
What is video bitrate?
Bitrate is how much data flows per second of video, measured in Mbps (megabits per second) or kbps. It directly controls the trade-off between quality and file size.
A higher bitrate preserves more detail, especially important for screen recordings with small UI text. A lower bitrate produces smaller files but introduces compression artifacts.
For most 1080p screen recordings, 6-12 Mbps is the practical sweet spot. Below 4 Mbps and text starts to blur. Above 20 Mbps and you're paying a size cost with diminishing returns.
How file size is calculated
Formula
File size (MB) =
(video_bitrate_mbps + audio_bitrate_mbps)
ร duration_seconds รท 8
Bitrate is in bits per second. Since 1 byte = 8 bits, we divide by 8 to convert to bytes, then by 1,000,000 to get megabytes.
This gives you the raw data size before any container overhead (typically <2%). Real-world files may vary slightly depending on the encoder and codec efficiency.
Bitrate reference guide for screen recordings
Bitrate Resolution Use case Quality
1-3 Mbps Up to 720p Small Slack clips, quick previews โ Low
4-6 Mbps 720p - 1080p Twitter/X, Notion embeds โ Good
6-12 Mbps 1080p Product demos, walkthrough recordings โโ Excellent
12-25 Mbps 1080p - 1440p High-motion screen content, editors โฆ Overkill for web
25+ Mbps 4K+ Archive or post-production masters โ Archival only
Frequently asked questions
For screen recordings with text and UI, 6-10 Mbps at 1080p is the sweet spot. Text stays sharp, file sizes remain manageable. If you are recording fast motion or a game at 60 fps, push to 12-15 Mbps. Going above 20 Mbps rarely improves perceptual quality for screen content.
Not directly. File size is determined by bitrate ร duration, and bitrate is independent of fps. However, to maintain the same visual quality at 60 fps vs 30 fps, you typically need roughly 1.3-1.5ร more bitrate to encode the extra frames cleanly. The calculator assumes a fixed bitrate regardless of fps.
Bitrate is a rate: how fast data flows (bits per second). File size is the total accumulation of that data over time. A 10 Mbps video that runs for 60 seconds produces a 75 MB file. Think of bitrate as the water pressure and file size as how full the bucket gets.
Container overhead, metadata, subtitles, and variable bitrate (VBR) encoding can all push the actual file above the calculated estimate. Screen recorders also often default to CRF (constant quality) mode which increases bitrate during fast motion. The formula gives a reliable baseline for CBR exports.
A few practical options: use H.265/HEVC instead of H.264 for roughly 40% smaller files at the same quality; drop to 30 fps if your content doesn't need 60; crop to the actual area of interest rather than recording a full 4K screen; and run it through a compressor such as our free Video Compressor for Mac before sharing.
How to use the video bitrate calculator
1. Pick a preset or enter your settings
Start with one of the presets at the top: UI Recording, Slack, Twitter/X, Notion, or ProductHunt. Each preset sets the right resolution, fps, and bitrate target for that destination. Or dial in custom values if you're targeting a specific encoder configuration.
2. Choose your calculation direction
Use "File size from bitrate" when you already know your encoder settings and need to know how big the output will be, useful before recording a long session. Use "Bitrate from target size" when you have an upload limit (like Slack's 1 GB cap or Twitter's 512 MB limit) and need to work backwards to find the right bitrate.
3. Check the quality indicator
The quality bar gives you a quick signal on whether your chosen bitrate is appropriate for the resolution. For screen recordings, "Excellent" means text will render crisply. "Low" often indicates you'll see compression artifacts around UI elements, tooltips, and small text.
4. Verify against the platform limits
The platform table shows the upload limits and recommendations for the most common destinations. Cross-check your calculated file size against those limits before exporting. If you're over the limit, lower the bitrate or consider compressing with our MOV Compressor tool.
5. Recording on a Mac? Match these settings at export
If you record with CursorClip, the export window lets you choose the format (MP4 or MOV), the resolution (720p, 1080p, or 4K when the recording is that large), the frame rate (24, 30, or 60 fps), the codec (H.264 or HEVC), and a quality level. You pick a quality level rather than an exact bitrate, so use this calculator to choose the resolution and frame rate that fit your size limit. CursorClip also zooms in on your clicks automatically, so viewers can follow small UI details.
For Mac screen recordings
Record it polished, then export at the size you need
CursorClip zooms in on your clicks automatically and records system audio and your mic together. When you export, pick MP4 up to 4K (or a GIF for clips under 10 minutes) and choose the resolution and frame rate that fit your upload limit. Free to record and edit. A license to export.
Mac only ยท No account required
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