By Geoff Mangum
Quick and easy math for determining the break and target (spot above center of cup X inches or centimeters straight up the fall line) get golfers nicely ball-parked for putts inside 10′ or 3 meters, where there is typically one flat, same slope from ball to hole.
In ENGLISH units, a 1% Slope breaks 1/24th the distance (0.5″ per 12-inch foot). So any Slope divided by 2 gives the basic unit of break per foot of putt distance.
A. Simple formula (assumes flat slope at “usual” green speed Stimp 10′ and “smart” ball speed):
Slope / 2 = inches of break per foot of distance.
Distance (feet) x Slope / 2 = inches of break for any distance.
Example: 5 foot putt on 3% slope, 3% / 2 = 1.5″ per foot, so 5′ x 1.5″ = 7.5″ of break measured from center of hole up fall line.
B. More exact formula that does not assume green speed is “usual”:
Slope x (Stimp / 20) = inches of…
Read the rest of what Geoff has to say about Putting Zone Basic Math in the November 2015 Monthly Handicap Improver here: