Rules Guy: Is it legal to use a Stimpmeter to gauge the speed of the greens before playing?

A man using a Stimpmeter on a green

What do the rules say about using a Stimpmeter to measure the green speed before playing?

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The Rules of Golf are tricky! Thankfully, we’ve got the guru. Our Rules Guy knows the book front to back. Got a question? He’s got all the answers.

I’m the type of guy who likes to know what I’m getting into before I play. Can I use a Stimpmeter to check the speed of the greens on the day of a competition? —Douglas Wilson, Blairgowrie, Scotland

Nae, Douglas, at least in stroke play — Rule 5.2 prohibits rolling a ball on the surface of any putting green on the course before a round in stroke play.

If you were to do this on more than one putting green, you would be disqualified.

In match play, however, practicing beforehand on the course is allowed. All that said, if we’re talking Scotland, green speeds will be in the single digits, promise. Give those putts a good rap!

For more green-reading guidance from our guru, read on …

Green reading book
Rules Guy: Is it against the rules to use glasses to access the info in a green-reading book?
By: Rules Guy

Our club has green-reading contour books, but the print is so small that I can’t make out the details. I took a picture of each page with my cell phone to be able to enlarge the image enough to see the slopes.  A competitor called me out, citing a prohibition against electronics in tournament play. I said it was previously compiled material. Who was right in this blowup? —Scott Kulla, via e-mail

In all-caps, bold-faced, oversized type: YOU! A player can access or review any material that was preprinted or created prior to the round. There is no issue with accessing that info on your iPhone — with one caveat: If you’re using this material to help read a line of play on a putting green, your “blown up” version must still meet the size and scale requirements in Clarification 4.3a/1.

Still, it’s not always smart to reach for that smartphone. Calling a friend for advice or studying an analysis of strokes made during the round, as examples, would be operator errors and land you in hot water, Rules-wise … and placing the phone on a bed of dry rice wouldn’t fix it.

Need help unriddling the greens at your home course? Pick up a custom Green Book from Golf Logix.

Got a question about the Rules? Ask the Rules Guy! Send your queries, confusions and comments to We promise he won’t throw the book at you.

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