Google Sheets does not natively support a way to convert numbers into their written form. However, by using the BAHTTEXT function in conjunction with GOOGLETRANSLATE we can approximate a written form.

Syntax

SUBSTITUTE(GOOGLETRANSLATE(BAHTTEXT([number])), " baht", )

Notes

• The efficacy of this technique is dependent on the accuracy of Google Translate. As Google Translate is error-prone, so too is this technique.
• It typically fails with larger numbers.