Data Storage Converter

1. 01Enter a value and its unitType the number and pick which unit it is currently in — bit, byte, or any decimal or binary storage unit.
2. 02Read the base, decimal, and binary resultsThe result is grouped into three panels: base units (bit/byte), decimal SI units (kB–TB), and binary IEC units (KiB–TiB), so the two systems are never mixed together.
3. 03Compare the decimal and binary value for the same amountFor any size larger than a few bytes, the decimal and binary panels will show different numbers for the "same" storage — that difference is expected, not an error.

• Understanding why a drive shows less space than advertisedManufacturers label drive capacity in decimal GB/TB (base 1000), but operating systems often display it in binary GiB/TiB (base 1024) while still calling it "GB" — converting between the two explains the gap.
• Converting a file size for a size-limit ruleCheck whether a file measured in one unit fits under a limit stated in another (for example, converting MiB to MB for an upload cap stated in decimal terms).
• Working out a bandwidth or transfer estimateConvert between bits (commonly used for network speeds, like Mbps) and bytes (commonly used for file sizes) without mixing up the factor of 8 between them.

• 1 kB vs 1 KiB1 kB (decimal) = 1,000 bytes. 1 KiB (binary) = 1,024 bytes. They are close but not the same — 1,024 bytes is exactly 1 KiB, but only 1.024 kB.
• 1 GB vs 1 GiB1 GB (decimal) = 1,000,000,000 bytes. 1 GiB (binary) = 1,073,741,824 bytes — about 7.4% more. This is the main reason a "1 TB" drive (decimal) shows roughly 931 GiB in a binary-reporting operating system.
• Bits and bytes1 byte = 8 bits. A 100 Mbps (megabit-per-second) connection transfers at most 12.5 MB (megabytes) per second, not 100 — a common source of confusion between network-speed units and file-size units.

Decimal SI prefixes (kB, MB, GB, TB) are powers of 1000, following the same convention as kilometers or kilograms, and are the convention used by storage-device manufacturers and most macOS/Linux "used space" displays. Binary IEC prefixes (KiB, MiB, GiB, TiB) are powers of 1024, matching how computer memory actually addresses data in binary, and are what Windows has historically displayed while still labeling the result "KB", "MB", or "GB". Neither is more "correct" than the other for describing a raw byte count — they are different, equally valid units that happen to look similar at small scales and diverge more as the numbers grow.

That statement is only true for the binary unit KiB, not for the decimal unit kB. Because operating systems and software have historically used the ambiguous label "KB" to mean either 1000 or 1024 bytes depending on context, the IEC binary prefixes (KiB, MiB, GiB, TiB) were introduced specifically to remove that ambiguity. This tool always uses kB/MB/GB/TB for exact base-1000 values and KiB/MiB/GiB/TiB for exact base-1024 values, so a result is never left ambiguous.

A bit is a single binary digit; a byte is 8 bits. Network and connection speeds are conventionally measured in bits per second (e.g., Mbps, Gbps), while file and storage sizes are conventionally measured in bytes (e.g., MB, GB) — mixing the two up by a factor of 8 is one of the most common storage-unit mistakes.

Why does my hard drive show less space than the number on the box?

Drive manufacturers label capacity using decimal GB/TB (base 1000), while most operating systems report free/used space using binary GiB/TiB (base 1024) but still display the label "GB"/"TB". A drive sold as "1 TB" (1,000,000,000,000 bytes) shows as roughly 931 GiB in that binary display — no space is actually missing, it is the same byte count in two different unit systems.

Is 1 KB equal to 1000 or 1024 bytes?

It depends on which system is being used, which is exactly the ambiguity this tool avoids. 1 kB (decimal, lowercase k) is defined as exactly 1,000 bytes. 1 KiB (binary) is defined as exactly 1,024 bytes. Historically, software has used "KB" to mean either one depending on context.

How many bits are in a byte?

Exactly 8 bits make 1 byte — this factor of 8 never changes, in either the decimal or binary system.

Which system should I use?

Use decimal (kB/MB/GB/TB) when matching a manufacturer-stated drive/media capacity, and binary (KiB/MiB/GiB/TiB) when matching how an operating system, memory, or many file managers report actual used/free space. When in doubt, this tool shows both at once so you can compare directly.

Is my data saved?

No. Everything is calculated in your browser; nothing is sent to a server.