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CalcHub Blog
March 26, 20264 min read

Video File Size Calculator — Estimate Storage Before You Shoot

Calculate video file size by resolution, frame rate, bitrate, and duration. Plan storage for shoots, estimate upload times, and compare codec efficiency.

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You're heading out for a full-day shoot. The question is whether a single 256GB card will hold everything — or whether you're carrying three cards and hoping for the best. File size math is easy once you know the variables.

Run the numbers on CalcHub's video file size calculator before you pack your bag.

What Determines Video File Size

File size comes down to three things multiplying together: bitrate (how many megabits per second), duration, and a small efficiency factor from the codec.

File size (GB) ≈ (Bitrate in Mbps × Duration in seconds) ÷ 8 ÷ 1000

That's it. A 100 Mbps codec recording for 60 seconds = 100 × 60 ÷ 8 ÷ 1000 = 0.75 GB.

How to Use the Calculator

  1. Enter video resolution (1080p, 4K, 6K, etc.)
  2. Select frame rate (24, 30, 60, 120 fps)
  3. Enter bitrate (check your camera's spec sheet or settings menu)
  4. Enter recording duration
  5. Get estimated file size in MB and GB
The CalcHub calculator also lets you flip it — enter a target file size and duration to find the maximum bitrate you can use.

File Sizes by Common Recording Profiles

FormatBitrate10 min file1 hour file
1080p H.264 (YouTube)16 Mbps~1.2 GB~7 GB
4K H.264 (consumer)80 Mbps~6 GB~36 GB
4K H.265/HEVC60 Mbps~4.5 GB~27 GB
4K ProRes LT330 Mbps~24.8 GB~148 GB
4K ProRes 422 HQ708 Mbps~53 GB~318 GB
6K RAW (cinema)2000+ Mbps~150 GB~900 GB
The jump from consumer H.264 to professional ProRes is enormous. A one-hour corporate interview in 4K ProRes HQ fills nearly a third of a terabyte.

Codec Efficiency Matters

H.265 (HEVC) typically stores the same quality as H.264 at about half the bitrate. This is why many newer cameras default to H.265 — same image quality, smaller files. The tradeoff is more CPU-intensive to edit. If your editing computer struggles with HEVC, you may need to transcode to a proxy format first.

Planning Storage for a Shoot Day

A typical wedding day: 8 hours, but maybe 4 hours of actual recording. Shooting 4K at 80 Mbps in H.264 — that's roughly 4 × 60 × 0.36 GB/minute = 86 GB. Add a safety margin, and 128GB cards with a 256GB backup drive covers you comfortably.

For cinema work with RAW or ProRes, double or triple your estimates and bring more cards than you think you need.

Why is my actual file size different from the estimate?

Bitrate-based codecs aren't fixed — they're variable bitrate (VBR). Scenes with lots of movement and detail use more bits than static shots. The estimate is an average. Fixed bitrate (CBR) recording gives more predictable file sizes.

How does frame rate affect file size?

Higher frame rates = more frames per second = larger files, roughly proportionally. 60fps at the same bitrate as 24fps will be about 2.5x larger. However, some cameras automatically increase bitrate at high frame rates, making the jump even bigger.

What's the fastest way to reduce file size without switching cameras?

Lower the bitrate in your camera's settings (if adjustable), use H.265 instead of H.264, or shoot at a lower frame rate for non-action content. You can also batch-transcode in post to a more efficient codec if original quality is preserved.

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