File Size Converter
Convert between bytes, kilobytes, megabytes, gigabytes, and terabytes — with both decimal (1 KB = 1,000 B) and binary (1 KiB = 1,024 B) standards shown side by side.
| Bytes (B) | 1,000,000,000 |
| Kilobytes (KB) | 1,000,000 |
| Megabytes (MB) | 1,000 |
| Gigabytes (GB) | 1 |
| Terabytes (TB) | 0.001 |
| Bytes (B) | 1,000,000,000 |
| Kibibytes (KiB) | 976,562.5 |
| Mebibytes (MiB) | 953.67 |
| Gibibytes (GiB) | 0.931323 |
| Tebibytes (TiB) | 9.095e-4 |
How to use this tool
- Enter an amount and pick its unit (decimal like MB, or binary like MiB).
- Read the equivalent in bytes.
- Compare the two tables to see your size in both decimal (SI) and binary (IEC) units.
How it works
Decimal units step by 1,000 (1 GB = 10⁹ bytes) and are used by storage manufacturers and networking. Binary units step by 1,024 (1 GiB = 2³⁰ bytes) and are what operating systems like Windows traditionally report.
That mismatch is why a '500 GB' drive shows up as roughly 465 'GB' in Windows — the drive really is 500 × 10⁹ bytes, but Windows is displaying gibibytes (GiB) while labeling them GB.
Frequently asked questions
What's the difference between KB and KiB?
1 KB (kilobyte) = 1,000 bytes; 1 KiB (kibibyte) = 1,024 bytes. The gap grows with each step: 1 TB = 10¹² bytes but 1 TiB ≈ 1.0995 × 10¹² bytes — nearly 10% more.
Why does my hard drive show less space than advertised?
Manufacturers advertise in decimal units (1 TB = 10¹² bytes) while many operating systems display binary units. 1 TB works out to about 931 GiB, which looks like 'missing' space but isn't.
How many MB in a GB?
1,000 MB in a GB using decimal units, or 1,024 MiB in a GiB using binary units.