File Size Converter
Convert between bytes, KB, MB, GB, TB, and PB — both decimal (SI) and binary (IEC) units — instantly in your browser.
Equivalent values
Bytes
1,000,000,000 B
Kilobytes
1,000,000 KB
Megabytes
1,000 MB
Gigabytes
1 GB
Terabytes
0.001 TB
Petabytes
0.000001 PB
How to convert file sizes
- Choose Decimal or Binary mode.
- Enter the file size value and select its unit.
- All equivalent values appear instantly in the table below.
- Hover any row to reveal its copy button.
Decimal (SI) vs Binary (IEC) units
There are two standards for measuring file sizes, which is why you'll see different numbers depending on your OS or application.
Decimal (SI)
1 KB = 1,000 B • 1 MB = 1,000,000 B
Used by hard drive manufacturers, storage media specs, and network speeds.
Binary (IEC)
1 KiB = 1,024 B • 1 MiB = 1,048,576 B
Used by most operating systems (Windows, macOS, Linux) when displaying file sizes.
This is why a "500 GB" hard drive shows as ~466 GB on Windows — the drive maker uses decimal (500 × 10⁹ bytes), but Windows displays in binary (divide by 1024³ = 1.07 × 10⁹).
Privacy — runs in your browser
All calculations run locally using JavaScript arithmetic. No data is uploaded to any server. No signup required.
Frequently Asked Questions
Is a kilobyte 1,000 or 1,024 bytes?
It depends on context. In the SI (decimal) system, 1 KB = 1,000 bytes. In the IEC (binary) system, 1 KiB = 1,024 bytes. The IEC introduced "kibibyte (KiB)" in 1998 to eliminate the ambiguity, but operating systems still often say "KB" when they mean KiB.
Why does my OS show less space than the drive is advertised for?
Drive manufacturers use decimal units (1 GB = 10⁹ bytes), while most operating systems display binary units (1 GiB = 2³⁰ bytes = 1,073,741,824 bytes). A 1 TB drive is really 10¹² bytes, which is only ~931 GiB.
What is a petabyte?
A petabyte (PB) is 10¹⁵ bytes in decimal (1,000 TB) or 1,125,899,906,842,624 bytes in binary (1,024 TiB). At 2025 storage scales, major cloud providers operate at petabyte to exabyte scale.