Windshield wiper blades that fit hook arms often list various sizes for the hook: 1/2" & 3/4", 9x3 & 9x4, and 9mm. Are these all different sizes, or are any equivalent and, if so, which ones? More fundamentally, what do the sizes measure?

1 Answer 1


According to the Windshield Wiper Guide (which may not be the most credible), 9x4 is the same as 3/4", and 9x3 as 1/2". I was also able to put a blade that was supposed to fit both 3/4" and 1/2" hooks on a car that is listed as taking 9x3 blades.

From measuring a wiper blade, 9mm is the width of the hook, while 3/4" and 1/2" refer to the height of the hook.

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