Technology

Video File Size Calculator: How Big Is Your Video?

Calculate exactly how many GB a video takes from its bitrate and length. Free, instant, no sign-up — plus a quick-reference table for 1080p, 4K, ProRes and CCTV.

Data verified · June 2026
Edited by Martín Rodríguez
Formula verified by automated tests
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Edited by: Martín Rodríguez (editorial policy )

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How to use this calculator

Follow this tool’s steps, then review its formula, assumptions, and limits below.

Step by step

01

Enter your data

02

Tap the Calculate button

03

Check the result

This calculator tells you exactly how big a video file will be from its bitrate (Mbps) and duration (minutes). The shortcut formula is File Size (GB) = [Bitrate (Mbps) × Duration (seconds)] ÷ 8,192, because a byte is 8 bits and 1 GB = 1,024 MB. So a clip recorded at 10 Mbps for 60 minutes weighs 4.39 GB. Useful for videographers sizing SD cards before a shoot, YouTubers estimating upload time, broadcasters pre-allocating server space, and anyone planning storage for CCTV or screen recordings. Knowing the size upfront avoids running out of card mid-ceremony or under-provisioning a NAS.

When to use this calculator

A wedding videographer shooting 8 hours of 4K H.264 at 100 Mbps needs ~351 GB of SD card storage — calculating this beforehand avoids running out of cards mid-ceremony.
A live sports broadcaster encoding at 15 Mbps for a 3-hour game must pre-allocate ~19.8 GB of server space for the recorded stream before the event begins.
A YouTube creator uploading 4K footage at 35 Mbps for a 20-minute video knows the file will be ~5.13 GB, so they can estimate the transfer time on a 100 Mbps connection.
A surveillance admin running a 4 Mbps camera 24/7 must budget ~42.2 GB per camera per day to size the NAS for a 30-day retention policy.
A podcast editor receiving ProRes 422 HQ files at 220 Mbps for a 2-hour recording expects a ~193 GB file and confirms drive space before accepting the project.

Video File Size by Format and Duration (Binary GB ÷ 8,192)

Format / Codec	Typical Bitrate	30 min	1 hour	8 hours
480p H.264 (streaming)	1 Mbps	0.22 GB	0.44 GB	3.5 GB
720p H.264 (YouTube)	5 Mbps	1.10 GB	2.20 GB	17.6 GB
1080p H.264 (standard)	10 Mbps	2.20 GB	4.39 GB	35.2 GB
1080p H.264 (high quality)	25 Mbps	5.49 GB	10.99 GB	87.9 GB
4K H.264 (consumer camera)	60 Mbps	13.18 GB	26.37 GB	211 GB
4K H.265/HEVC (efficient)	35 Mbps	7.69 GB	15.38 GB	123 GB
4K ProRes 422	706 Mbps	155 GB	310 GB	2,483 GB
1080p ProRes 422 HQ	220 Mbps	48.3 GB	96.7 GB	774 GB
CCTV / Surveillance (720p)	1–4 Mbps	0.22–0.88 GB	0.44–1.76 GB	3.5–14.1 GB
Zoom / Video Call (720p)	1.5 Mbps	0.33 GB	0.66 GB	5.3 GB
Netflix 4K HDR (streaming)	15–25 Mbps	3.3–5.5 GB	6.6–11.0 GB	53–88 GB

Fuente: Apple ProRes White Paper (2022), YouTube Upload Encoding Guidelines, Netflix Tech Blog. Fórmula: File Size (GB) = [Bitrate (Mbps) × Duración (s)] ÷ 8,192 (convención binaria).

How it works

How It's Calculated

The relationship between bitrate, duration, and file size comes straight from the definition of a bit rate — the number of bits processed per second.

File Size (bits)  = Bitrate (bits/second) × Duration (seconds)
File Size (bytes) = File Size (bits) ÷ 8
File Size (KB)    = File Size (bytes) ÷ 1,024
File Size (MB)    = File Size (KB)    ÷ 1,024
File Size (GB)    = File Size (MB)    ÷ 1,024

Combined shortcut (Mbps in, GB out):
  File Size (GB) = [Bitrate (Mbps) × Duration (s)] ÷ 8,192

Worked example — 10 Mbps for 60 minutes:

Duration in seconds: 60 × 60 = 3,600 s

Megabits: 10 × 3,600 = 36,000 Mb

Megabytes: 36,000 ÷ 8 = 4,500 MB

GB: 4,500 ÷ 1,024 = 4.39 GB

Handy rule of thumb: every 1 Mbps of bitrate uses ≈ 0.44 GB per hour of recording. Multiply by your bitrate and hours to estimate any clip in your head.

> Note on GB vs GiB: Consumer storage (hard drives, SD cards) is often marketed in decimal GB (1 GB = 1,000,000,000 bytes), while operating systems report in binary GiB (1 GiB = 1,073,741,824 bytes). This calculator uses the ÷ 8,192 (binary) convention, so its GB figure matches what your OS and most camera displays show.

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Quick-Reference Table: File Size by Format

Common video formats, their typical bitrates, and resulting file sizes (binary GB, ÷ 8,192):

> Bitrate values sourced from codec documentation, the Apple ProRes White Paper (2022), YouTube upload-encoding guidelines, and Netflix Tech Blog encoder specifications.

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Worked Scenarios

Case 1: Indie Documentary — 4K H.265 @ 50 Mbps, 4 hours of raw footage

Duration: 4 × 3,600 = 14,400 seconds

File Size = (50 × 14,400) ÷ 8,192 = 87.9 GB

A 128 GB SD card is plenty; a 64 GB card would not be.

Case 2: Corporate Livestream Archive — 1080p H.264 @ 8 Mbps, 90 minutes

Duration: 90 × 60 = 5,400 seconds

File Size = (8 × 5,400) ÷ 8,192 = 5.27 GB

Fits easily on a 16 GB USB drive with room to spare.

Case 3: Security Camera System — 16 cameras @ 4 Mbps, 30-day retention, 24/7

Per camera per day: (4 × 86,400) ÷ 8,192 = 42.2 GB/day

16 cameras × 42.2 GB × 30 days = 20,250 GB ≈ 20.3 TB

A NAS with 24 TB usable (e.g., 4 × 8 TB drives in RAID 5) would be appropriate.

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Common Mistakes

1. Confusing Mbps (megabits) with MBps (megabytes): Bitrate is almost always in bits per second. Forgetting the ÷ 8 inflates your estimate 8×. Check whether your spec sheet says "Mb/s" or "MB/s."

2. Ignoring container and audio overhead: MP4, MOV and MKV add metadata, index tables and audio. AAC stereo at 320 kbps adds ~0.14 GB/hour. On short clips, overhead can be 1–5% of the total.

3. Treating VBR as if it were the peak bitrate: Most modern codecs (H.264, H.265, VP9) use Variable Bitrate. A camera rated "up to 100 Mbps" may average only 40–60 Mbps. This calculator assumes constant bitrate (CBR) — for VBR, enter the average, not the peak.

4. Forgetting GB vs GiB when comparing to the OS: A file is 4.39 GiB by the ÷ 8,192 binary convention but 4.72 decimal GB by the ÷ 8,000 marketing convention. Mixing the two causes confusion when a card says one number and Windows shows another.

5. Not multiplying for multi-camera shoots: Recording 3 angles at once triples storage. Editors often forget this when estimating raw ingest before an edit session.

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Related Calculators

Plan the rest of your storage and bandwidth with the Technology category on Hacé Cuentas, which covers byte conversions, streaming bitrate, and storage planning.

Worked Example

Bitrate 10 Mbps, duration 60 min → 3,600 seconds

(10 × 3,600) ÷ 8,192

= 4.39 GB

4.39 GB

Frequently asked questions

How do I calculate a video file size from bitrate and duration?

Use File Size (GB) = [Bitrate (Mbps) × Duration (seconds)] ÷ 8,192. First multiply bitrate by seconds to get megabits, divide by 8 for megabytes, then by 1,024 for GB. Example: a 10 Mbps clip for 60 minutes = (10 × 3,600) ÷ 8,192 = 4.39 GB. A quick mental shortcut is that 1 Mbps uses about 0.44 GB per hour.

How many GB is one hour of video?

It depends entirely on bitrate. One hour at 1 Mbps is ~0.44 GB; at 10 Mbps (typical 1080p) it is 4.39 GB; at 35 Mbps (4K H.265) it is 15.4 GB; at 60 Mbps (4K consumer camera) it is 26.4 GB. The rule of thumb: GB per hour ≈ bitrate in Mbps × 0.44.

What is bitrate and how does it affect file size and quality?

Bitrate is the amount of data encoded per second, in Mbps or Kbps. Higher bitrate keeps more visual detail but makes bigger files, and the relationship is direct: doubling the bitrate doubles the file size for the same length. For reference, Netflix streams 4K HDR at 15–25 Mbps, while cinema cameras can record 2,000+ Mbps in RAW.

Why does my actual file differ from the calculated estimate?

Three reasons: (1) most encoders use Variable Bitrate, so the real average can be lower than the rated peak; (2) audio, metadata and container overhead add bytes the video bitrate alone doesn't capture; (3) the binary-vs-decimal GB gap (1 GiB = 1.074 decimal GB) can shift the number a few percent versus what storage packaging advertises.

What bitrate should I use to upload 4K to YouTube?

YouTube's upload guidelines recommend roughly 35–68 Mbps for 4K (2160p) SDR at 24–30 fps and 53–68 Mbps for 4K HDR; for 1080p they suggest 8–12 Mbps. At 35 Mbps, a 10-minute 4K clip is about 2.56 GB before upload. YouTube re-encodes your file afterward, so the viewer's quality is independent of your upload size.

How much storage do I need for a full day of 4K wedding video?

An 8-hour shoot at 4K H.264 on a consumer camera (~60 Mbps average) is about 211 GB of raw footage; a dual-camera setup roughly doubles that to ~422 GB. Most pros carry 2–3 × 128 GB cards per camera plus an SSD backup, and provision at least 25% over the estimate as a safety buffer.

Does the formula change for H.265 (HEVC) vs H.264?

No — the file-size math depends only on bitrate and duration, not the codec. What changes is efficiency: H.265/HEVC delivers roughly the same visual quality as H.264 at about half the bitrate, so a 4K H.265 file at 35 Mbps looks comparable to 4K H.264 at 60–70 Mbps while using nearly half the storage.

How do I size storage for a 24/7 security camera system?

Use Total (GB) = Bitrate (Mbps) × 86,400 ÷ 8,192 × Cameras × Retention Days. Eight cameras at 4 Mbps with 14-day retention need: 4 × 86,400 ÷ 8,192 × 8 × 14 ≈ 4,725 GB ≈ 4.7 TB. Add ~20% for the file system and any RAID parity.

What's the difference between video bitrate and internet speed?

Bitrate (e.g. 25 Mbps) measures how dense the data is inside the video stream. Transfer speed (e.g. a 100 Mbps connection) measures how fast data moves between devices. If your upload is 100 Mbps and the file is 4.39 GB (~37.7 Gbit), the theoretical upload time is about 6 minutes, before protocol overhead.

Should I enter the bitrate in Mbps or Kbps?

This calculator expects Mbps. If your device reports Kbps, divide by 1,000 first: 1,500 Kbps = 1.5 Mbps. Consumer gear (GoPro, iPhone, DSLR) usually shows Mbps, while webcams, Zoom and older CCTV often use Kbps. Mixing the two without converting throws the result off by a factor of 1,000.

Sources & references

Methodology & trust

Editorial

Technology calculator with its formula verified automatically against NIST — Special Publication 811: Definitions of Bits, Bytes, and Prefixes, per our editorial policy and methodology.

Updates

Updated: June 2026. Parameters are verified periodically against the cited sources.

Privacy

Calculations run 100% in your browser. We do not store or transmit your data.

Limitations

Indicative results. For critical decisions, consult a professional.

📌 How to cite this calculator

Rodríguez, M. (2026). Video File Size Calculator: How Big Is Your Video?. Hacé Cuentas. https://hacecuentas.com/en/video-storage-bitrate-duration

Content licensed under CC-BY 4.0 — reuse it citing the source with a link to Hacé Cuentas.

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