JIS

What it does

JIS(text)

JIS(text) is the language-dependent width-conversion name documented for changing half-width English letters or katakana to full-width forms. The function name and supported character transformations depend on Excel’s language settings.

Try it

This spelling is not registered in the OneCalc preview engine, so calculation returns #NAME? here. See the function guide for Excel availability.

Under the documented Japanese mapping, =JIS("abc") produces full-width ａｂｃ. A string containing only characters outside the half-width conversion set is retained. The preview returns #NAME? because its engine does not resolve this spelling; that support limit is not a reading from Excel.

Quirks

“Single-byte” and “double-byte” describe legacy character-width conventions here, not UTF-8 byte lengths. This is not a generic Unicode normalization operation. The current Windows-oriented catalogue exposes DBCS for the width conversion and does not supply an executable JIS entry; locale/name resolution is part of the missing context.

How to implement

Choose the language-specific mapping first, then scan text with a table of supported half-width letters and kana. Handle voiced kana sequences as the mapping requires and leave unrelated characters intact. Preserve UTF-16 text and invalid-text policy rather than counting encoded bytes. A whole-string NFKC call is not a substitute: it changes a broader class of characters and converts compatibility forms in another direction. The exact mapping outside the documented Japanese examples needs locale-specific evidence.

Rust code

This entry has no Rust implementation yet.

No implementation has been published with a Handbook test suite for this function.

Version differences

No same-input comparison between named Excel builds is recorded for this function here. The documented behaviour below is not a measurement of every Excel release.

Alternatives

DBCS is the other documented name for conversion to full-width forms; ASC performs the opposite width direction.

Named variants

No named variants are recorded yet.