GB to GiB Converter
A gigabyte (GB) is 1,000,000,000 bytes (decimal SI). A gibibyte (GiB) is 1,073,741,824 bytes (binary IEC). One GB ≈ 0.9313 GiB. This is why a 1 TB drive shows up as roughly 931 GiB in some operating systems.
Formula
GiB = GB × 0.9313225746154785
Reverse:
GB = GiB × 1.073741824
Formula variables
- GB — size in decimal SI gigabytes. 1 GB = 10⁹ bytes = 1,000,000,000 bytes.
- GiB — size in binary IEC gibibytes. 1 GiB = 2³⁰ bytes = 1,073,741,824 bytes.
- 0.9313225746154785 — the ratio 10⁹ / 2³⁰, exact.
Worked Examples
Example 1: 1 GB to GiB
- 1 GB = 1,000,000,000 bytes.
- 1 GiB = 1,073,741,824 bytes.
- 1,000,000,000 ÷ 1,073,741,824 = 0.9313225746154785.
- Result: 1 GB ≈ 0.9313 GiB.
Example 2: 500 GB SSD to GiB
- 500 GB = 500,000,000,000 bytes.
- 500,000,000,000 ÷ 1,073,741,824 = 465.66128730773926.
- Result: 500 GB ≈ 465.66 GiB. Windows will typically show this drive as "465 GB".
Example 3: 1 TB drive to GiB
- 1 TB = 1,000,000,000,000 bytes.
- 1,000,000,000,000 ÷ 1,073,741,824 = 931.3225746154785.
- Result: 1 TB ≈ 931.32 GiB. This is the familiar "931 GB" seen in some operating systems.
Common Conversion Table
| GB (SI) | GiB (IEC) | Typical device |
|---|---|---|
| 1 | 0.931323 | Small file |
| 8 | 7.450581 | Single-layer DVD |
| 16 | 14.901161 | USB flash drive |
| 32 | 29.802322 | Small SSD |
| 64 | 59.604645 | Large USB |
| 128 | 119.209290 | Small SSD |
| 256 | 238.418579 | SSD |
| 500 | 465.661287 | SSD |
| 1000 | 931.322575 | 1 TB drive |
Why a 1 TB Drive Shows as 931 GB
This is the single most common source of consumer confusion about digital storage. The explanation:
- Drive manufacturers use decimal SI: a "1 TB" drive holds 1,000,000,000,000 bytes (10¹²).
- Many operating systems display capacity using binary IEC units (2⁴⁰ for TiB, 2³⁰ for GiB) but label them with SI prefixes ("GB").
- Converting: 10¹² bytes ÷ 2⁴⁰ = 0.9095 TiB, or in GiB: 10¹² ÷ 2³⁰ = 931.32 GiB.
- So the drive shows as "931 GB" while actually holding 1 TB (SI) or 0.9095 TiB (IEC).
Modern macOS (since 10.6) uses decimal SI and shows 1 TB drives as "1 TB". Windows and most Linux distributions use binary values with SI labels, showing "931 GB".
Real-World Uses
- Storage shopping: Understanding why a "500 GB" SSD shows up as 465 GiB in Windows.
- Cloud storage billing: Some providers bill by GB (decimal) while others bill by GiB (binary) — the difference is about 7%.
- Software development: Correctly using GB vs GiB in documentation and code prevents subtle bugs.
- RAM: RAM sizes are almost always quoted in binary GiB but often labeled "GB". A "16 GB" RAM stick is really 16 GiB = 17,179,869,184 bytes.
Unit Definitions
Gigabyte (GB)
A decimal SI unit of digital information equal to exactly 1,000,000,000 bytes (10⁹). Standard in storage marketing and international commerce.
Gibibyte (GiB)
A binary IEC unit of digital information equal to exactly 1,073,741,824 bytes (2³⁰). Standardized in IEEE 1541-2002 and used internally by many operating systems.
Related Converters
Frequently Asked Questions
What is the difference between GB and GiB?
GB is a decimal SI unit equal to 1,000,000,000 bytes. GiB is a binary IEC unit equal to 1,073,741,824 bytes. One GB ≈ 0.9313 GiB.
Why does a 1 TB drive show as 931 GB?
Manufacturers use decimal SI (1 TB = 10¹² bytes). Many operating systems display binary IEC values but with SI labels. 10¹² ÷ 2⁴⁰ ≈ 0.9095 TiB ≈ 931 GiB, shown as "931 GB".
How do you convert GB to GiB?
Multiply the GB value by 0.9313225746154785. For example, 100 GB × 0.9313225746154785 ≈ 93.13 GiB.
Which is bigger, GB or GiB?
GiB is bigger. One GiB = 1,073,741,824 bytes, while one GB = 1,000,000,000 bytes. So one GiB is about 7.37% larger than one GB.
Should I use GB or GiB?
Use GB when referring to decimal SI values (typical of marketing), and GiB when referring to binary IEC values (typical of operating system internals). The IEEE 1541-2002 standard recommends GiB for the binary value, but adoption has been partial.