"Will this video blow through my data plan?" "Why is my one-minute clip 400MB?" Video sizes feel arbitrary until you know the three numbers that drive them. Once you do, you can estimate any video's size in your head — and stop being surprised by storage warnings.

The three factors that set file size

Resolution

The pixel grid — 480p, 720p, 1080p, 4K. Each step roughly doubles the pixels, and size climbs with it.

Frame rate

30fps is standard; 60fps doubles the frames per second and can add 30–50% to file size at the same resolution.

Bitrate — the real boss

Bitrate is how much data per second the file uses, and it overrides everything else: a high-bitrate 720p file can outweigh a lean 1080p one. Modern phones shoot at generous bitrates, which is why "just a minute" of footage is often hundreds of MB.

The practical size table

Typical modern-phone recording (H.264, default bitrates), per minute of video:

480p (SD)

About 30–60 MB per minute. Fine for messaging-app legibility, soft on detail.

720p (HD)

About 60–120 MB per minute. The sweet spot for shareable clips — sharp on phones, kind to storage.

1080p (Full HD)

About 100–250 MB per minute. The default quality most people actually need.

4K (UHD)

About 300–600 MB per minute — two hours fills a 256GB phone at this rate. Record it for the future; share it after compressing.

HEVC instead of H.264

Cuts these numbers roughly in half at the same visual quality. Most recent phones offer it in camera settings.

Streaming is sized differently

Streaming replaces "file size" with data usage, and adaptive streaming changes the math:

The platform decides, not the file

Your 4K upload becomes a ladder of renditions. A viewer on mobile data might consume 480p-level data (about 5–10 MB per minute) watching the same video that a fiber user streams at 4K (50–100+ MB per minute).

This is why links beat attachments

Sending the file means sending its full size; sending a link lets each viewer's player spend only what their connection allows. It is the difference between forcing 400MB through a chat app and letting grandma watch the same clip for 8MB of her data.

Quick mental math for common situations

"Can I email this?"

10 minutes of 1080p ≈ 1.5–2.5GB — no. Compress to 720p/CRF 28 (roughly 200–400MB for 10 minutes — still usually no for a 25MB email cap) or send a link.

"Will this upload before my flight?"

At a typical 10 Mbps upload, 1GB takes about 13 minutes. Size ÷ 10 Mbps × 8 ≈ seconds.

"Why did my storage vanish?"

Two hours of holiday 4K at ~450 MB/min ≈ 54GB. It is not a mystery; it is the bitrate.

Shrinking any of these numbers

Drop resolution one step, cap frame rate at 30, switch the codec to HEVC, or trim dead footage — each independently cuts size, and they stack. And when the goal is sharing rather than storing, upload to a streaming host and let viewers' players pick the spend instead of your file dictating it.