sourcemirrors.org
Units

File Size Converter

Convert between bytes, KB, MB, GB, TB and their binary counterparts (KiB, MiB, GiB) — with both the decimal (1000) and binary (1024) definitions side by side.

UnitDecimal (1000)Binary (1024)
Bytes——
KB / KiB——
MB / MiB——
GB / GiB——
TB / TiB——

Decimal vs. binary units

There are two conventions for file-size units, and mixing them up is the classic source of confusion. The decimal (SI) system uses powers of 1000: 1 MB = 1,000,000 bytes. The binary (IEC) system uses powers of 1024 and has its own names: 1 MiB = 1,048,576 bytes. Storage manufacturers advertise in decimal, while many operating systems report in binary — which is why a drive sold as “1 TB” shows up as roughly 931 GiB once it’s formatted.

Common conversions

Frequently asked questions

What is the difference between MB and MiB?

A megabyte (MB) is 1,000,000 bytes under the decimal SI definition. A mebibyte (MiB) is 1,048,576 bytes (1024 x 1024). Storage vendors advertise in decimal MB/GB; operating systems often report binary MiB/GiB, which is why a "1 TB" drive shows as roughly 931 GiB.

Should I use 1000 or 1024?

Use 1000-based units (KB, MB, GB) for marketing and network figures, and 1024-based units (KiB, MiB, GiB) when you mean the values an operating system reports. This converter shows both at once.

More tools

Verification

Checksum & Hash Calculator

MD5, SHA-1, SHA-256 & SHA-512 of any file or text. Verify a download against its published checksum.

Bandwidth

Download Time Calculator

Estimate transfer time from a file size and your connection speed.

Encoding

Base64 Encoder / Decoder

Encode text to Base64 or decode it back, with full UTF-8 support.

Encoding

URL Encoder / Decoder

Percent-encode text for URLs, or decode an encoded URL back to text.

Format

JSON Formatter / Validator

Pretty-print, validate, or minify JSON. Clear error messages.

Generate

QR Code Generator

Make a QR code from any text or link; download as PNG or SVG.