Which system should I use, decimal (KB, MB) or binary (KiB, MiB)?

Use decimal units (KB, MB, GB) for network speeds and advertised storage capacity. Use binary units (KiB, MiB, GiB) when referring to file sizes and memory as reported by your operating system.

File Size Converter - Bytes, KB, MB, GB, TB, PB

Q: What is the difference between a Megabyte (MB) and a Mebibyte (MiB)?

A Megabyte (MB) is a decimal unit (1,000,000 bytes) used by storage manufacturers. A Mebibyte (MiB) is a binary unit (1,048,576 bytes) used by operating systems like Windows to report file sizes and memory.

Q: Why does my 1 TB hard drive only show 931 GB in Windows?

This is due to the difference between decimal and binary measurements. The manufacturer sells 1 Terabyte (1 trillion bytes). Windows measures this in Gibibytes (powers of 1024), which comes out to approximately 931 GiB (often displayed as 'GB' by Windows).

Q: What is the difference between a bit and a byte?

A 'bit' is the smallest unit of data (a 0 or 1). A 'byte' is a group of 8 bits. File sizes are measured in bytes, while internet speeds are usually measured in bits per second.

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File Size Converter

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Decimal (Powers of 1000)

Used for network speeds and by storage manufacturers.

Bits (b)

Bytes (B)

Kilobytes (KB)

Megabytes (MB)

Gigabytes (GB)

Terabytes (TB)

Petabytes (PB)

Binary (Powers of 1024)

Used by operating systems like Windows to measure file size and memory.

Bits (b)

Bytes (B)

Kibibytes (KiB)

Mebibytes (MiB)

Gibibytes (GiB)

Tebibytes (TiB)

Pebibytes (PiB)

About the File Size Converter

We built this tool to make converting digital storage units simple and clear. One of the biggest points of confusion in computing is the difference between how storage is marketed and how it's actually measured by an operating system. Our converter solves this by showing you both systems—Decimal (powers of 1000) and Binary (powers of 1024)—side-by-side.

The best feature of our tool is its live, bi-directional calculation. You can type a number into any of the input boxes, and all other units will update instantly. This makes it incredibly easy to see how a value translates across different scales, from the smallest bits to massive petabytes. It's a fast, client-side tool designed for developers, students, and anyone who needs accurate data storage conversions.

How to Use the Tool

Simply enter a number into any of the input fields.
All other fields in both the Decimal and Binary columns will update in real-time to show the converted values.
You can type in any box—for example, start with gigabytes or mebibytes, and all other units will adjust.
Click the copy icon next to any value to instantly copy it to your clipboard.

Frequently Asked Questions

What is the difference between a Megabyte (MB) and a Mebibyte (MiB)?

This is the most common question about file sizes. A Megabyte (MB) is a decimal unit, meaning 1 MB = 1,000 Kilobytes = 1,000,000 bytes. This is how hard drive manufacturers and network providers measure speed. A Mebibyte (MiB) is a binary unit, meaning 1 MiB = 1,024 Kibibytes = 1,048,576 bytes. This is how most operating systems, like Windows, measure file size and RAM.

Why does my 1 TB hard drive only show 931 GB in Windows?

This is because of the difference between the decimal and binary systems. The hard drive manufacturer sells you 1 Terabyte (1 trillion bytes). However, Windows measures storage in Tebibytes (TiB), Gibibytes (GiB), etc. So, 1 trillion bytes is equal to about 0.909 Tebibytes or 931 Gibibytes, which is what Windows displays.

Which system should I use?

It depends on the context. If you are talking about networking, data transfer speeds, or storage capacity as advertised by manufacturers, you should use the decimal units (KB, MB, GB). If you are referring to file sizes, memory, or capacity as reported by your operating system, you should use the binary units (KiB, MiB, GiB).

What is the difference between a bit and a byte?

A "bit" is the smallest unit of data in computing, representing a single 0 or 1. A "byte" is a group of 8 bits. File sizes are almost always measured in bytes and its multiples (kilobytes, megabytes), while internet speeds are usually measured in bits per second (e.g., Mbps - megabits per second).

Is this tool's calculation accurate?

Yes. The tool uses the official definitions for both decimal (base 1000) and binary (base 1024) prefixes to perform its calculations, providing precise conversions across all units.