Video File Size Calculator
Estimate how big a video will be from its resolution, frame rate, bitrate and length, or work out the bitrate needed to stay under an upload limit. All the math runs instantly in your browser.
Every resolution at recommended bitrates
| Resolution | Video bitrate | File size | Per minute |
|---|
Recommended bitrates are ballpark figures based on YouTube's H.264 upload guidance; H.265 is estimated at about 60% and AV1 at about 50% of H.264. MB = 1,000,000 bytes.
How to use the Video File Size Calculator
- Choose a mode: File size from bitrate, or Bitrate for target size.
- Pick the resolution, frame rate and codec, or choose Custom and type the width and height.
- Enter the duration and audio bitrate, then type a video bitrate or press Use recommended.
- Press Calculate (it also updates live) to see the file size, bitrate and bits per pixel.
- For an upload limit, switch to Bitrate for target size, pick a limit such as 10 MB and read the maximum video bitrate to enter in your encoder.
Video size and bitrate formulas
- File size (bytes) = (video bitrate + audio bitrate, in bits per second) × duration (seconds) ÷ 8
- Maximum total bitrate (bps) = target size (bytes) × 8 ÷ duration (seconds)
- Maximum video bitrate = maximum total bitrate − audio bitrate (minus a few percent of margin for the container)
- Bits per pixel = video bitrate ÷ (width × height × frames per second)
Example 1: 10 minutes of 1080p at 8 Mbps with 128 kbps audio is (8,000,000 + 128,000) × 600 ÷ 8 = 609,600,000 bytes, about 610 MB (581 MiB).
Example 2: to fit a 60-second clip into a 25 MB upload limit with a 3% margin: 25,000,000 × 0.97 × 8 ÷ 60 ≈ 3.23 Mbps in total. Minus 128 kbps audio leaves about 3.1 Mbps for video, above the 480p ballpark in H.264 and enough for 720p with H.265 (about 3 Mbps) or AV1 (about 2.5 Mbps).
Recommended bitrates by resolution (H.264)
These are YouTube's recommended upload bitrates for SDR video in H.264, a good reference for high-quality files. Streaming services deliver much lower bitrates, and screen recordings or talking-head videos often look fine at half these values.
| Resolution | 24–30 fps | 48–60 fps | Size per minute (30 fps) |
|---|---|---|---|
| 360p | 1 Mbps | 1.5 Mbps | 7.5 MB |
| 480p | 2.5 Mbps | 4 Mbps | 18.75 MB |
| 720p | 5 Mbps | 7.5 Mbps | 37.5 MB |
| 1080p | 8 Mbps | 12 Mbps | 60 MB |
| 1440p | 16 Mbps | 24 Mbps | 120 MB |
| 2160p (4K) | 35–45 Mbps | 53–68 Mbps | about 300 MB |
| 4320p (8K) | 80–160 Mbps | 120–240 Mbps | about 900 MB |
Source: YouTube Help, "Recommended upload encoding settings" (SDR, H.264). Per-minute sizes are video only; 4K and 8K use the calculator's midpoints of 40 and 120 Mbps.
Tips for hitting a size limit
- Use two-pass encoding with a target bitrate (not CRF) when the file must stay under a hard limit; a single-pass or constant-quality encode can overshoot.
- Lower the resolution before the bitrate. A clean 720p video looks better than a blocky 1080p one at the same bitrate.
- Drop the frame rate from 60 to 30 fps for talking heads, slides and screen recordings; it saves roughly a third of the bitrate needed.
- Trim first. Cutting dead air at the start and end with the Video Trimmer is the cheapest way to save space, then shrink the rest with the Video Compressor.
- Check the source resolution, frame rate and bitrate of an existing file with the Video Resolution Checker.
Frequently asked questions
How do you calculate video file size?
File size (bytes) = (video bitrate + audio bitrate in bits per second) × duration in seconds ÷ 8. A 10-minute 1080p video at 8 Mbps with 128 kbps audio is (8,000,000 + 128,000) × 600 ÷ 8 = 609,600,000 bytes, about 610 MB. The container (MP4, MKV) usually adds less than 1–2%.
Does resolution change the file size?
Not directly. File size depends only on bitrate and duration. Resolution, frame rate and codec decide how much bitrate you need for good quality: a 4K video needs several times the bitrate of 1080p to look as clean, which is why it ends up larger.
What bitrate do I need to fit a video under 10 MB or 25 MB?
Total bitrate (bps) = size in bytes × 8 ÷ seconds. For a 60-second clip under 10 MB that is 10,000,000 × 8 ÷ 60 ≈ 1.33 Mbps in total. Subtract the audio (for example 96 kbps) and keep a few percent of margin, which leaves about 1.2 Mbps for video, enough for decent 720p or good 480p.
What is a good bitrate for 1080p video?
YouTube recommends about 8 Mbps for 1080p at 24–30 fps and 12 Mbps at 48–60 fps for H.264 uploads. Efficient codecs need less: H.265 (HEVC) typically looks similar at roughly 40% less bitrate, and AV1 at roughly half, although results depend on the content and encoder settings.
What does bits per pixel mean?
Bits per pixel (bpp) = video bitrate ÷ (width × height × fps). It shows how much data each pixel gets per frame. For H.264, around 0.1 bpp usually looks good for typical footage, below about 0.05 gets blocky in motion, and fast action, grain or confetti needs more.
Why is my real file a little different from the estimate?
Most encoders use variable bitrate, so the average can drift from the target, especially for very short clips or with constant-quality modes (CRF). The container adds headers and an index, and audio may be encoded differently. Use the safety margin in reverse mode when you must stay under a hard limit.
Why does Windows show a smaller size?
This tool reports decimal units (1 MB = 1,000,000 bytes), which upload limits and storage makers use. Windows uses binary units (1 MiB = 1,048,576 bytes) but labels them MB, so the same file appears about 4.6% smaller there. Both values are shown in the result.