A data storage converter handles the confusion between decimal (SI) and binary (IEC) units. Hard drive makers use decimal GB (1,000,000,000 bytes) while operating systems traditionally used binary GB (1,073,741,824 bytes) — creating the infamous "missing" storage discrepancy. Enter any value to see all units at once.
Data Storage Converter
Unit Reference
| Unit | Symbol | Decimal (SI) | Binary (IEC) |
|---|---|---|---|
| Kilobyte | KB / KiB | 1,000 bytes | 1,024 bytes |
| Megabyte | MB / MiB | 1,000,000 bytes | 1,048,576 bytes |
| Gigabyte | GB / GiB | 1,000,000,000 bytes | 1,073,741,824 bytes |
| Terabyte | TB / TiB | 1,000,000,000,000 bytes | 1,099,511,627,776 bytes |
| Petabyte | PB / PiB | 1015 bytes | 250 bytes |
How to Convert Data Storage Units
Converting data storage units requires choosing the right standard. The decimal (SI) standard uses powers of 1,000 and is used by storage manufacturers and most internet speed contexts. The binary (IEC) standard uses powers of 1,024 and is used internally by operating systems. Both are correct — they just measure differently.
When to Use SI (Decimal)
Use SI units when working with hard drive capacities, SSD specs, network transfer rates, and cloud storage quotas. A 1TB hard drive, a 512GB SSD, or a 100GB cloud backup plan all use decimal (SI) measurement. This is the standard for hardware specifications and marketing.
When to Use IEC (Binary)
Use IEC binary units when working with operating system file sizes, RAM capacity, or programming contexts. Windows, Linux, and older macOS versions display file sizes using binary units (often mislabeled as GB instead of GiB). When a system reports free space, it is using binary units. This explains why a 1TB drive shows as ~931 GB on Windows.
Quick Mental Math
For rough conversions: 1 GB (decimal) ≈ 0.931 GiB (binary). To convert GB to GiB, multiply by 0.931. To convert GiB to GB, multiply by 1.074. For most everyday use, the difference is small enough that GB and GiB can be treated interchangeably — just remember the discrepancy when comparing manufacturer specs to OS display.
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). Hard drive manufacturers use decimal GB, which is why a 1TB drive shows as ~931 GB in Windows (which uses binary). This tool supports both standards — select SI (decimal) or IEC (binary) above.
How many bytes are in a megabyte?
In decimal (SI): 1 MB = 1,000,000 bytes (1,000 KB). In binary (IEC): 1 MiB = 1,048,576 bytes (1,024 KiB). Most operating systems historically used binary units but labeled them as MB — which is why file sizes on Windows appear smaller than what the drive manufacturer advertises.
How many gigabytes is 1 terabyte?
In decimal (SI): 1 TB = 1,000 GB. In binary (IEC): 1 TiB = 1,024 GiB. Consumer storage (hard drives, SSDs) is marketed in decimal TB, so a 1TB drive contains exactly 1,000,000,000,000 bytes, which equals ~931.32 GiB as shown by most operating systems.
Why does my hard drive show less storage than advertised?
Hard drive manufacturers measure in decimal (1TB = 1,000,000,000,000 bytes). Windows measures in binary (1GB = 1,073,741,824 bytes) but labels it GB. So a 1TB drive shows as ~931GB in Windows. macOS switched to decimal display in OS X Lion, so a 1TB drive shows correctly as ~1TB on modern Macs.
Is this data storage converter free?
Yes, completely free with no signup required. All conversions run instantly in your browser.