What this tool does
Converts between all data storage units in both SI (powers of 1000) and IEC (powers of 1024) standards.
Converter and calculator
Data Storage Converter
Convert between bits, bytes, kilobytes, megabytes, gigabytes, terabytes, and more. Handles both decimal (SI) and binary (IEC) definitions.
Complete guide
How to use Data Storage Converter
Unit converters guide for data storage converter users.
Data storage units have a confusing dual system. In decimal (SI), 1 KB = 1,000 bytes. In binary (IEC), 1 KiB = 1,024 bytes. Hard drive manufacturers use decimal; operating systems typically report in binary. This is why a '1 TB' hard drive shows as ~931 GB in Windows.
This converter handles both systems. Toggle between SI (KB, MB, GB) and IEC (KiB, MiB, GiB) to see both interpretations.
SI vs IEC
SI: 1 KB = 1,000 B, 1 MB = 1,000,000 B. IEC: 1 KiB = 1,024 B, 1 MiB = 1,048,576 B. Hard drives use SI; OSes report in IEC.
How to use it
Enter a value and select the unit. All other units update instantly. Toggle SI/IEC to switch between the two standards.
Quick checklist
- Hard drive capacity is advertised in SI (decimal) units.
- Windows reports storage in IEC (binary) units — hence the 'missing space'.
- 1 TB hard drive = ~931 GiB as shown by Windows.
- For RAM, IEC units (MiB, GiB) are the norm since memory uses binary addressing.
Answers
Data Storage Converter FAQs
Why does my 1 TB drive show less in Windows?
Drive manufacturers use SI (1 TB = 1,000,000,000,000 bytes). Windows reports in IEC (1 TiB = 1,099,511,627,776 bytes). A 1 TB drive is ~909 GiB.
What is the difference between GB and GiB?
1 GB = 1,000,000,000 bytes (SI). 1 GiB = 1,073,741,824 bytes (IEC). They differ by about 7%.
Which standard should I use?
Use SI when specifying storage capacity (matches manufacturer labels). Use IEC when measuring memory or interpreting OS file-size reports.
How many bytes in a gigabyte?
1 GB (SI) = 1,000,000,000 bytes. 1 GiB (IEC) = 1,073,741,824 bytes.