Calculator tool
How this calculator works
Use the explanation to understand the formula, assumptions, and practical limits behind the calculator result.
Decimal vs Binary Storage Units
Two competing standards for storage measurement cause persistent confusion:
| Unit | Symbol | Definition | Bytes |
|---|---|---|---|
| Kilobyte | KB | bytes | 1,000 |
| Megabyte | MB | bytes | 1,000,000 |
| Gigabyte | GB | bytes | 1,000,000,000 |
| Terabyte | TB | bytes | 1,000,000,000,000 |
| Kibibyte | KiB | bytes | 1,024 |
| Mebibyte | MiB | bytes | 1,048,576 |
| Gibibyte | GiB | bytes | 1,073,741,824 |
| Tebibyte | TiB | bytes | 1,099,511,627,776 |
Storage vendors (hard drives, SSDs, USB drives) use decimal (GB): 1 TB = bytes.
Operating systems (Windows, older macOS) display binary (GiB): 1 TiB = bytes.
Why Your 1 TB Drive Shows as 931 GB
The drive contains exactly 1 trillion bytes. Windows displays it as 931 GiB, calling it 'GB'. No storage is lost — only units differ. A 4 TB drive shows as ~3.64 TiB in Windows.
Storage Planning Reference
| Content Type | Typical File Size | 1 TB Holds Approximately |
|---|---|---|
| JPEG photo (12 MP) | 4–6 MB | 170,000–250,000 photos |
| RAW photo (24 MP) | 25–40 MB | 25,000–40,000 photos |
| HD video (1080p, H.264) | 1–4 GB/hour | 250–1,000 hours |
| 4K video (H.265) | 7–15 GB/hour | 65–140 hours |
| Music (MP3 320kbps) | 8–10 MB | 100,000–125,000 songs |
| Word document | 0.05–0.5 MB | 2M–20M documents |
Frequently asked questions
What is the difference between GB and GiB?
GB (gigabyte) is a decimal unit: 1 GB = 1,000,000,000 bytes (10^9). GiB (gibibyte) is a binary unit: 1 GiB = 1,073,741,824 bytes (2^30). The difference is about 7.4% — small per unit, but significant at scale. A 4 TB NAS drive contains 4 × 10^12 bytes. Windows reports it as 3,637.8 GiB (showing 'GB' but meaning GiB). The IEC introduced the binary prefixes (KiB, MiB, GiB, TiB) in 1998 to resolve the ambiguity, but hardware vendors continue using decimal GB and operating systems often still display binary values mislabelled as 'GB'.
How much storage do I need for video production?
Video storage requirements depend heavily on codec and resolution. 1080p footage shot on a DSLR or mirrorless camera at 100 Mbps (Canon, Sony) uses about 45 GB per hour. 4K ProRes (used in professional post-production) runs 880 GB to 2.1 TB per hour. Consumer 4K H.265 (from a smartphone) compresses to roughly 7–15 GB per hour. A standard budget: capture at 2× your estimated shoot time, then add 3× for editing scratch space and proxies, then factor in archive storage. A typical one-day commercial shoot with 6 hours of 4K footage may require 500 GB capture + 1.5 TB working storage.
How do I calculate how many photos fit on a memory card?
Divide card capacity in bytes by average file size: a 256 GB (decimal) memory card = 256,000,000,000 bytes. A 24 MP RAW file averages 30 MB = 30,000,000 bytes. Photos: 256,000,000,000 ÷ 30,000,000 ≈ 8,533 RAW files. For JPEG at 8 MB average: 32,000 photos. Mixed RAW+JPEG shooting roughly halves the RAW count. Always leave 5–10% unused on memory cards to maintain write speed and card health — performance degrades when cards approach 95–100% capacity.
Should I plan storage in GB or GiB for capacity planning?
Plan in decimal GB if you are specifying or purchasing storage hardware — vendors use decimal and contracts/quotes reference decimal. Plan in GiB if you are working within an OS file system or software that reports in binary. For budgeting purposes, always assume the OS will show about 7% less than the rated capacity. On a 10 TB NAS: budget 9.3 TiB of actual usable space after unit conversion, then subtract another 15–20% for RAID overhead and filesystem metadata if using RAID 5/6. A 10 TB raw NAS in RAID 5 with 4 drives delivers roughly 30 TB raw capacity, ~27.9 TiB, minus overhead ≈ 22–24 TiB usable.
