Byte Counter — String Size Calculator
Count bytes, characters, and code points in any text. Shows UTF-8, UTF-16, and ASCII sizes. Free online tool.
15
Characters
18
UTF-8 Bytes
32
UTF-16 Bytes
144
Bits
Character count15
UTF-8 size18 bytes (0.018 KB)
UTF-16 size32 bytes
ASCII characters14 of 15
Code points15
Max code pointU+1F30D
Minimum encodingUTF-8 (4-byte)
UTF-8 Byte Breakdown
14
1-byte (ASCII)
0
2-byte
0
3-byte
1
4-byte (emoji)
Why Count Bytes?
String length in characters is not the same as byte size. A single emoji like 🌍 is 1 character but 4 bytes in UTF-8. Knowing byte size is essential for database column limits, API payload sizes, HTTP headers, and file storage.
UTF-8 vs UTF-16
UTF-8 uses 1-4 bytes per character and is the web standard. UTF-16 (used by JavaScript and Windows) uses 2 or 4 bytes per character. ASCII characters always take 1 byte in UTF-8 and 2 bytes in UTF-16.