What is the difference between KB and KiB?

KB (kilobyte) in SI/decimal notation = 1,000 bytes. KiB (kibibyte) in IEC/binary notation = 1,024 bytes. Hard drive manufacturers use decimal; operating systems typically use binary.

How is text byte size calculated?

The tool calculates byte size using TextEncoder (UTF-8) where ASCII characters are 1 byte and most Unicode characters are 2–4 bytes.

Byte Size Calculator

Converts file sizes between bytes, KB, MB, GB, and TB using both decimal (SI: 1 KB = 1000 bytes) and binary (IEC: 1 KiB = 1024 bytes) prefixes. Also calculates the byte size of any text string in UTF-8, UTF-16, or ASCII encoding. Useful for storage planning, API payload sizing, and bandwidth calculations.

Convert file size

Bytes

1,000,000,000 bytes

Decimal (SI)

1 GB

Binary (IEC)

953.674 MiB

Bits

8,000,000,000 bits

Calculate string byte size (UTF-8)

Enter a size in any unit or paste text to see its byte count — in both decimal and binary prefixes.

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