Convert bytes to KB, MB, GB and TB without guessing the factor
Byte-size conversion looks simple until you hit the question that quietly breaks spreadsheets, capacity plans and log dashboards: is a kilobyte 1000 bytes or 1024? Both answers are correct depending on context, and mixing them is how a storage estimate ends up off by several percent. This converter shows your value in every unit at once and lets you switch between the decimal SI standard (1 KB = 1000 B) and the binary IEC standard (1 KiB = 1024 B), so you can read the right number for the job instead of doing error-prone mental math. Enter a figure in any unit — bytes, kilobytes, gigabytes — and the whole ladder updates instantly.
How to use it
- Pick decimal or binary depending on your context.
- Type a value and choose its unit.
- Read the converted value on every other row.
- Copy the exact figure you need into your doc or ticket.
Decimal versus binary, and why both exist
The decimal units — kilobyte, megabyte, gigabyte — are powers of 1000 and follow the same SI prefixes used everywhere else in science and engineering. Drive manufacturers, internet service providers and cloud bandwidth bills all use them, which is why a "1 TB" disk holds a trillion bytes. The binary units — kibibyte, mebibyte, gibibyte — are powers of 1024 and exist because memory addressing is binary, so RAM, buffers and most file sizes line up naturally on powers of two. The confusion is almost entirely a labelling problem: operating systems frequently compute in binary but print the decimal-looking abbreviations GB and MB, so the same file appears to have two different sizes on two different screens.
Where the mismatch bites in practice
Capacity planning is the classic trap. Provisioning "500 GB" of storage means something different to a vendor selling decimal gigabytes than to a filesystem reporting binary gibibytes, and the few-percent gap compounds at the terabyte and petabyte scale. The same issue shows up in monitoring: a metrics pipeline that ingests raw byte counts but renders them with a binary divisor will disagree with a billing system that uses a decimal one. Pick a standard per context, label it explicitly, and convert at the boundary rather than letting two conventions meet silently inside the same chart.
Pair it with the other reference tools
When you are sizing payloads rather than disks, the Base64 Encoder & Decoder is a reminder that Base64 inflates data by roughly a third, which matters when you budget request sizes. For bit-level work, the Number Base Converter moves between binary, octal, decimal and hex, and the Hash Generator helps when you need a fixed-length digest of a file regardless of its byte size. Keeping these in one tab means you can move from a raw byte count to a human-readable size and back without leaving the page.
Quick reference
One kilobyte is 1000 bytes; one kibibyte is 1024 bytes. One megabyte is one million bytes; one mebibyte is 1,048,576 bytes. One gigabyte is one billion bytes; one gibibyte is 1,073,741,824 bytes. The relative difference is about 2.4% at the kilo scale, 4.9% at mega, 7.4% at giga and roughly ten percent by tera — small enough to ignore in casual conversation, large enough to matter in a contract, an SLA or a capacity forecast.
Further reading
Two companion articles go deeper: KB vs KiB, MB vs MiB explains the decimal and binary unit systems, while why your hard drive shows less space than advertised applies them to a real disk.