Synonyms for gauge

a measuring instrument for measuring and indicating a quantity such as the thickness of wire or the amount of rain etc. (noun)

• gage

accepted or approved instance or example of a quantity or quality against which others are judged or measured or compared (noun)

diameter of a tube or gun barrel (noun)

• bore
• caliber
• calibre

judge tentatively or form an estimate of (quantities or time) (verb)

• estimate
• approximate
• guess
• judge