Convert Bytes to Gigabytes Accurately

The two standards exist due to different perspectives:

• Binary (base 2): Used by computers and operating systems because they process data in binary form.
  Uses powers of 1024 (2¹⁰) for conversions.
• Decimal (base 10): Used in marketing and consumer labeling because people are more familiar with decimal systems.
  Uses powers of 1000 (10³) for conversions.

This discrepancy explains why a "100 GB" hard drive shows up as approximately 93 GB in your operating system.

These units were created by the International Electrotechnical Commission (IEC) to eliminate confusion:

• GB (gigabyte): Decimal system unit (1 GB = 1000³ bytes = 1,000,000,000 bytes)
• GiB (gibibyte): Binary system unit (1 GiB = 1024³ bytes = 1,073,741,824 bytes)

Unfortunately, many manufacturers still use "GB" to refer to both standards, creating confusion. When your computer shows a "100 GB" drive as 93 GB, it's actually displaying GiB but labeling it as GB.

This is the most common example of the binary vs decimal discrepancy:

• Manufacturers advertise 1TB as 1,000,000,000,000 bytes (decimal)
• Your operating system measures in binary, where 1 TiB = 1,099,511,627,776 bytes
• When your computer converts 1,000,000,000,000 bytes to binary:
  1,000,000,000,000 ÷ 1,099,511,627,776 ≈ 0.909 TiB
  Which is approximately 931 GB when using the binary standard

Additionally, some space is reserved for file system overhead, which further reduces available space.

Choose the appropriate standard based on your context:

• Use binary (1024-based) when:
  • Checking storage in operating systems (Windows, macOS, Linux)
  • Programming or working with computer systems
  • Calculating memory usage (RAM)
  • Determining actual usable space on storage devices
• Use decimal (1000-based) when:
  • Comparing advertised storage capacities
  • Understanding marketing materials for storage devices
  • Calculating data transfer rates from ISPs
  • General discussions with non-technical users

Required precision depends on your use case:

• Everyday use: Whole numbers or 1 decimal place are sufficient
• Storage planning: 1-2 decimal places for estimating needs
• Technical work: 2-4 decimal places for accuracy
• Programming: Exact integer conversions (no decimals) to avoid errors

Remember that the 7% difference between binary and decimal becomes more significant with larger storage sizes, so choosing the right standard is often more important than decimal precision.