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Video File Size Calculator

Estimate how large a video export will be from its duration, resolution, frame rate, bitrate and codec — with the calculation explained.

Picking a resolution fills in a typical bitrate.

108.7 MB

Estimated size for 90s at 10 Mbps (H.264)

How this is calculated

File size = (video bitrate × duration + audio bitrate × duration) ÷ 8. Your bitrate of 10 Mbps is adjusted to about 10.00 Mbps to reflect H.264 efficiency and 30 fps, then multiplied by 90 seconds and converted from bits to bytes.

Real exports vary by a few percent because most encoders use variable bitrate: quiet, static shots compress further than fast motion.

How it works

  1. 1Enter the clip duration.
  2. 2Choose a resolution — a typical bitrate is filled in for you.
  3. 3Set the frame rate, codec and audio bitrate.
  4. 4Read the estimate in KB, MB or GB with the maths shown.

Features

  • Codec efficiency for H.264, H.265, VP9, AV1 and ProRes 422.
  • Separate audio bitrate for voiceover and music.
  • Results in KB, MB or GB.
  • Bitrate suggestions per resolution, including 1080 × 1920 vertical.
  • A written explanation, not just a number.

Examples

  • 30-second Reel, 1080 × 1920, 10 Mbps H.264 → about 38 MB
  • 60-second TikTok, 1080p, 8 Mbps H.265 → about 36 MB
  • 10-minute video, 1080p, 12 Mbps → about 910 MB
  • 5-minute 4K clip, 45 Mbps → about 1.7 GB

Why bitrate matters more than resolution

Resolution sets how many pixels exist; bitrate sets how much data describes them each second. A 4K export at 5 Mbps looks worse than 1080p at 10 Mbps. When a file is too large, lower the bitrate before lowering resolution.

Practical upload limits

  • Instagram Reels: 4 GB maximum.
  • TikTok: around 287 MB on iOS, 72 MB on Android for in-app uploads.
  • YouTube: 256 GB — your connection is the limit.
  • Email and chat: usually 25 MB.

Tips

  • Estimate before you render — it is faster than exporting twice.
  • For mobile uploads target under 50 MB per minute of 1080p.
  • Confirm the frame with the Video Aspect Ratio Calculator.

Frequently Asked Questions

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