Video File Size & Bitrate Calculator

Calculate video file size from bitrate & duration, get the recommended bitrate, with platform presets.

Calculate video file size from bitrate and duration, or solve for bitrate. Get the recommended bitrate for 1080p, 4K and 8K — 100% in your browser.

About Video File Size & Bitrate Calculator

The Video File Size & Bitrate Calculator works out the relationship between video file size, bitrate, and duration: calculate video file size from a bitrate and duration, or solve for the bitrate or the length you need. Enter a duration (h/m/s), a video bitrate (kbps or Mbps) plus optional audio kbps, and a file size (MB or GB) — pick which one to "Solve for" and the rest is computed. You can also pick a resolution, frame rate, codec and quality target to get a recommended bitrate for 720p, 1080p, 1440p, 4K or 8K, or drop in a real video file to read its true duration, resolution, size and average bitrate. It estimates upload time, shows a bits-per-pixel quality read, gives MB-per-minute and GB-per-hour data rates, and checks whether your file fits caps like email, Discord, WhatsApp, TikTok or X — all 100% in your browser, nothing uploaded, no signup.

How to use Video File Size & Bitrate Calculator

  1. Choose what to compute with the 'Solve for' toggle: Size, Bitrate, or Duration — the matching field becomes the read-only result.
  2. Fill in the other two values: duration as hours/minutes/seconds, video bitrate with the kbps or Mbps toggle (plus optional audio kbps), and file size in MB or GB.
  3. To get a recommended bitrate, open the 'Recommended bitrate & quality' panel, set the resolution/fps/codec and a target quality (Low, Good, High or Pristine), then click 'Use this bitrate' to load the suggested Mbps into the calculator.
  4. Optionally load a real video file at the top to auto-fill its actual duration, size, resolution, and measured average bitrate, or click a YouTube preset (e.g. 1080p60 · 12M).
  5. Read the result on the right — file size plus MB-per-minute and GB-per-hour data rates — then set your upload speed (Mbps) to see an estimated upload time.
  6. Check the 'Will it fit?' panel to compare your file against common upload caps, and click a number in the platform table to load a recommended upload bitrate.
  7. Use the Reset button to restore every field to its defaults.

Frequently asked questions

Are my video files uploaded to a server?
No. When you load a video to auto-fill its details, it is read locally in your browser to measure duration, size, resolution, and average bitrate — nothing is ever uploaded, and the calculator itself is pure math that runs on your device.
How do I calculate video file size from bitrate and duration?
Use the core relation size (MB) = total bitrate (Mbps) × duration (seconds) ÷ 8, where total bitrate is your video bitrate plus any audio kbps. For example, 10 Mbps over 60 seconds is 10 × 60 ÷ 8 = 75 MB. Solving for bitrate or duration just rearranges the same formula.
What bitrate should I use for 1080p or 4K?
Set the resolution, frame rate and codec, then pick a quality target and the calculator suggests a bitrate range. As a rough H.264 guide: 1080p30 ≈ 8 Mbps, 1080p60 ≈ 12 Mbps, 1440p30 ≈ 16 Mbps, 4K30 ≈ 35–45 Mbps and 4K60 ≈ 53–68 Mbps. Efficient codecs like HEVC/H.265 and AV1 reach the same quality at roughly half the bitrate. Click 'Use this bitrate' to load the suggestion into the calculator.
How do I make a video fit Discord, email or another size limit?
Enter your video's duration and open the 'Will it fit?' panel — it checks your file size against caps like email/Gmail (25 MB), Discord (25 MB free / 500 MB Nitro), WhatsApp (16 MB), TikTok, X and more, and shows the maximum total bitrate (≤ X Mbps) that keeps it under each cap at your duration. Re-export at that bitrate to fit.
What is the 'bits per pixel' quality read?
It divides your video bitrate by resolution × fps to estimate encoding quality, then labels it relative to the selected codec (H.264, HEVC, VP9, AV1). Newer codecs hit the same quality at a lower bitrate, so the codec factor shifts the bands — it's an estimate only, since real encoder output varies.
Is it free and do I need an account?
Yes, it's completely free with no signup, account, or watermark — every calculation runs in your browser.

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