Q:

Calibrate + able = Calibratible? Calibratable?

What is the consensus on the correct form of calibrate + able suffix? Wiktionary lists only one proper entry for "calibratable". Automotive industries prefer to use "calibratible" because it matches the pronunciation (disclaimer: I work in one). Neither are accepted by spell-checkers.
Any thoughts or opinions?

A:

The only ngram that yields any results from calibrable, calibratable, calibriable and calibrateable is calibratable. It also has a Wiktionary entry. However, the paraphrasation is a lot more common. So unless you absolutely need a single word, just write can be calibrated.
If you do need a single word, everything points to calibratable. The University of Michigan considers it a word.

