# Kanji mode

> Kanji mode packs Shift-JIS double-byte characters into 13 bits each instead of the 16 bits they would take in byte mode. It exists because QR codes were invented in Japan for Japanese text.

Source: https://useqr.app/glossary/kanji-mode · Last reviewed 2026-08-21 · UseQR is free forever, MIT licensed, no signup.

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## The saving

Shift-JIS encodes a kanji character in two bytes — 16 bits. Kanji mode compresses the
valid Shift-JIS range into 13 bits, an 18% saving. Over a few hundred characters that is
a whole version.

## When it applies

Only to characters in the Shift-JIS double-byte ranges. Japanese text encoded as UTF-8 uses
three bytes per character in byte mode — 24 bits — so kanji mode is nearly twice as
efficient for Japanese content.

Chinese and Korean have no equivalent mode in the base standard; they go through byte mode
as UTF-8.

## Compatibility

Support is universal in Japan and good on modern phone cameras elsewhere. Because it
requires the reader to interpret Shift-JIS, mixed-script content is usually safer in
UTF-8 byte mode.