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Enter a value and click Convert// convert bytes · kb · mb · gb · tb instantly
Convert file sizes between bytes, KB, MB, GB, TB and more instantly. Free browser-based tool — no upload, no sign-up required.
Ready to convert
Enter a value and click ConvertType any number in the input field — supports decimals and very large numbers.
Select the source unit and target unit from the dropdowns, or use All Units mode.
Click Convert or press Enter — get instant result with formula and quick reference table.
This tool converts digital storage sizes between all common units — from bits to petabytes. It supports both decimal SI units (KB = 1000 bytes) and binary IEC units (KiB = 1024 bytes), making it accurate for both network calculations and OS-reported file sizes.
KB (Kilobyte) is a decimal unit equal to 1,000 bytes, defined by the SI standard. KiB (Kibibyte) is a binary unit equal to 1,024 bytes, defined by the IEC standard. Operating systems like Windows historically used KB to mean 1,024 bytes, which caused confusion. Modern usage follows the IEC standard: KiB for 1,024-byte binary multiples.
Hard drive manufacturers use decimal units (1 TB = 1,000,000,000,000 bytes), while Windows reports storage in binary units. So 1 TB (decimal) = ~0.909 TiB (binary), which Windows may display as ~931 GB. This is why a "1TB" drive appears smaller than expected.
In decimal (SI): 1 MB = 1,000,000 bytes (1,000 × 1,000). In binary (IEC): 1 MiB = 1,048,576 bytes (1,024 × 1,024). The difference is about 4.9%, which becomes significant for large storage sizes.
Mbps (Megabits per second) and MB/s (Megabytes per second) are both bandwidth units, but bits vs bytes differ by a factor of 8. To convert: 100 Mbps ÷ 8 = 12.5 MB/s. Internet speed is usually quoted in Mbps, while file transfer speeds show in MB/s.
In decimal (SI): 1 TB = 1,000 GB. In binary (IEC): 1 TiB = 1,024 GiB. Most consumer storage products use the decimal definition, so a 1 TB SSD contains 1,000 GB by that standard.
Yes! This tool supports bits (bit), kilobits (Kbit), megabits (Mbit), and gigabits (Gbit) in addition to all standard byte units. This is useful for network bandwidth calculations where speeds are commonly expressed in bits per second.
A Petabyte (PB) is a decimal unit equal to 1,000 Terabytes (or 1,000,000,000,000,000 bytes). It is used to describe very large data centers and cloud storage. The binary equivalent is a Pebibyte (PiB) = 1,024 TiB. As of 2026, the world generates several zettabytes of data per year.
This tool uses JavaScript's 64-bit floating-point numbers, which are accurate up to about 15–16 significant digits. For most practical file size conversions this is more than sufficient. Extremely precise scientific calculations may require specialized tools, but for everyday storage conversions this tool is fully reliable.
Understanding file sizes is essential in modern computing, whether you're a developer planning server storage, a network engineer calculating bandwidth, or simply trying to understand why your 1TB hard drive shows less space than expected. Our free File Size Converter makes it simple to convert between any digital storage units instantly — no installation, no sign-up required.
Digital storage is measured in bits and bytes. A bit is the smallest unit of data — a single binary digit (0 or 1). A byte consists of 8 bits and is the fundamental building block for file sizes. From bytes, larger units are derived in two ways:
The difference between these two standards is a common source of confusion. Hard drive manufacturers use decimal units (1 GB = 1,000,000,000 bytes), while operating systems have historically used binary units (1 GB = 1,073,741,824 bytes). The IEC introduced the kibibyte (KiB), mebibyte (MiB), and gibibyte (GiB) notation precisely to eliminate this ambiguity.
The International System of Units (SI) defines storage using powers of 1,000:
These units are used by hard drive manufacturers, solid-state drive (SSD) makers, cloud storage providers, and network bandwidth specifications. When you see "1TB SSD" in a product listing, that's 1,000,000,000,000 bytes in decimal.
The International Electrotechnical Commission (IEC) defines binary storage units using powers of 1,024:
Linux, macOS, and many programming languages use binary units internally, even if they display them with the "GB" or "MB" label. This is slowly being corrected as the industry adopts the GiB/MiB notation more consistently.
Network speeds are typically measured in bits per second (bps), not bytes. This is why your "100 Mbps" internet connection downloads files at roughly 12.5 MB/s — there are 8 bits in a byte, so you divide by 8 to convert.
Understanding this conversion is critical for developers building applications that transfer data over networks, or for anyone trying to estimate how long a file download will take.
This is one of the most common file size questions. A "1 TB" hard drive contains exactly 1,000,000,000,000 bytes by the manufacturer's (SI) definition. However, Windows traditionally reports storage capacity in binary units while labeling them with SI names. So:
No space is actually lost — it's purely a unit labeling difference. macOS (since 10.6 Snow Leopard) switched to SI units and correctly reports a 1 TB drive as "1 TB". Linux and modern Windows 11 versions are increasingly using proper IEC notation.
Here are some common file sizes to give you an intuitive sense of scale:
This tool offers two modes. In Simple Convert mode, enter a value, choose your source unit and target unit, then click Convert. Use the Swap button to quickly reverse the direction. The result shows the converted value, the formula used, and a quick reference with several common conversions.
In All Units mode, enter a value in any base unit and get a complete conversion table showing the equivalent in every supported unit simultaneously. This is ideal when you need to understand a file size across multiple contexts at once.