What Is Green Speed in Golf?

You’ve probably heard announcers on television mention stimpy greens or talk about how fast the putting surfaces are, but what exactly does green speed mean for your game? It’s one of those terms that gets thrown around a lot, yet many golfers aren’t entirely sure what it represents. This article will break down exactly what green speed is, how it’s measured, and most importantly, how a solid understanding of it can help you stop three-putting and start draining more putts.

Understanding Green Speed: More Than Just "Fast" or "Slow"

At its core, green speed is a uniform measurement of how far a golf ball will roll on a putting surface due to its own momentum. It’s not a measure of how good or bad the greens are, nor does it have anything to do with how fast the grass is growing. Instead, it’s a direct reflection of the friction of the putting surface. A low-friction, smooth green is “fast,” and a higher-friction surface is “slow.”

Several factors combine to determine the speed of a green on any given day:

• Mowing Height: This is the most significant factor. The shorter the blades of grass are cut, the less resistance they provide, and the faster the ball will roll. A head greenkeeper at a major championship might double-cut the greens in the morning, taking an almost unnoticeable amount of grass off to make them exceptionally quick.
• Rolling: Greens are often rolled with heavy, specialized machines that smooth out imperfections and compact the surface. Rolling reduces the space between soil particles and grass blades, making the surface firmer and faster.
• Moisture: Water adds friction. Greens that are wet from rain or morning dew will be significantly slower than greens that are dry and firm. This is why greens often speed up throughout a sunny day as they dry out.
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Different grass strains have different characteristics. Bentgrass, common in cooler climates, can be mowed very tightly and provides a smooth, fast surface. Bermuda grass, found in warmer regions, has a thicker blade and a pronounced grain, which can influence speed and direction.
• Grain: This refers to the direction the grass blades are growing. Putting "downgrain" (with the direction of growth) can make a putt noticeably faster, while putting "into the grain" will slow it down.

How They Measure It: The Stimpmeter Explained

So if a club tells you its greens are running at an "11," what does that actually mean? That number comes from a simple but ingenious tool called a Stimpmeter. It was invented by an amateur golfer named Edward Stimpson in the 1930s, who wanted a standardized way to measure the consistency of greens across a course.

A Stimpmeter is a 36-inch aluminum bar with a v-shaped groove running down the middle and a small notch about 30 inches up from the bottom end. The process of getting a "Stimp" reading is surprisingly straightforward:

1. A course superintendent finds a flat, level section of a representative putting green.
2. A golf ball is placed in the notch on the Stimpmeter.
3. The end of the bar is slowly lifted. When the ramp reaches an angle of about 20 degrees, gravity takes over and the ball is released from the notch, rolling down the groove and onto the green. It’s designed this way to ensure the ball is always released at the same starting speed.
4. They measure the distance the ball rolls (in feet) from the end of the Stimpmeter to where it comes to rest. They'll do this three times in one direction and take an average distance.
5. They then repeat the entire process in the exact opposite direction. This is done to negate the effects of any subtle, unnoticeable slope in the ground.
6. The average distance of all six rolls (three in each direction) is the official Stimp reading for that green. For instance, if the average roll is 11.5 feet, the greens are "stimping at 11.5."

To give you some context, here’s a general guide to what those numbers mean:

• Under 7: Very slow (might find this at a less-maintained local course)
• 7-9: Pretty slow to medium (typical for many daily-fee public courses)
• 9-11: Medium-fast (a common speed for private clubs and well-maintained courses)
• 11-13: Fast (the standard for tournament play and elite clubs)
• 13+: Extremely fast (reserved for major professional tournaments like The Masters and the U.S. Open, where even a tiny tap sends the ball skidding across the green)

Okay, So Why Should You Care? Adapting Your Game

Knowing the Stimpmeter's history is interesting, but what you really need to know is how to deal with different speeds on the course. You don't need a Stimpmeter in your bag, you just need a reliable process for calibrating your feel before and during your round.

Step 1: The Pre-Round Reconnaissance Mission

If you only do one thing before your round, make it this: spend 10 minutes on the practice green. Its surface condition will almost always match the greens on the course. This is your intel-gathering session. Don't just whack balls at a hole. Use this time with a purpose:

• The Distance Control Test: Grab three balls and find a 30-foot, relatively flat putt. Hit putts without trying to make them, your only goal is to lag the ball to "tap-in" range. Pay close attention to how much effort it takes. Is a small, compact stroke all you need, or do you require a bigger, more authoritative motion?
• Listen and Look: Fast, firm greens have a higher-pitched, "clicky" sound at impact. Slower, softer greens have a duller "thud." Watch how the ball rolls. Does it seem to coast forever? That's a fast green. Does it look like it's rolling through syrup and starts losing steam quickly? You're on slow greens today.

Step 2: Adjust Stroke Length, Not Tempo

This is probably the most valuable putting tip for managing speed. The biggest mistake amteur golfers make is trying to "hit" the ball harder on slow greens or being "delicate" and "deceling" on fast greens. Both actions destroy your tempo and lead to inconsistent distances.

Your goal is to maintain the same smooth rhythm on every putt. The only thing that should change is the length of your putting stroke.

• On FAST greens: Your swing thought should be to make a shorter, more compact stroke. A shorter backswing followed by a shorter follow-through. Trust that this smaller motion will be enough to get the ball rolling the required distance. Think less effort, more confidence.
• On SLOW greens: You need a longer stroke. A longer backswing and a longer follow-through. It is a bigger motion, but the tempo - the "one-two" beat of your stroke - should feel exactly the same as it does on a fast green. You are allowing a bigger motion to generate the speed, not a quicker, "hitty" jab at the ball.

Step 3: How Green Speed Radically Changes the Break

Pace and line are inseparable partners in putting. You cannot read a putt correctly without first knowing the speed. The fundamental rule is this: the faster the green, the more a putt will break. The slower the green, the less it will break.

Imagine rolling a marble down a slanted driveway. If you roll it very fast, it shoots down in a nearly straight line. If you just barely get it moving, it will bend significantly toward the low side. Putting is the same.

• Strategy for Fast Greens: You need to play more break - sometimes far more than you think. Aim higher on the high side and let the ball "die" into the hole on its last rotation. The ball is moving slowly as it approaches the hole, so gravity has maximum effect.
• Strategy for Slow Greens: You can be more aggressive. Since the ball is moving faster and has less time to be affected by the slope, you can take a more direct line. You can aim closer to the hole and hit the putt more firmly to "take the break out of it."

Putting It All Together on the Course

Once you’ve done your pre-round homework, stay mindful as you play. Be aware of how conditions might be changing. Is it a hot, windy day? The greens are likely getting firmer and faster. Did a surprise shower pass through? Expect them to slow down.

Pay special attention to grain and severe slopes:

• Uphill Putts: These will play even slower than a flat putt, especially when putting into the grain. Be aggressive and commit to hitting the ball past the hole. An uphill putt left short is one of the most common mistakes in golf.
• Downhill Putts: These will play much faster, and the break will be exaggerated. On slick, downhill putts, your only goal is to get the ball started on the right line. Think about a huge three-foot circle around the hole and just try to get the ball to finish somewhere in that circle. Prioritize lag-putting over trying to heroically make it.

Becoming a great putter isn’t about having a "perfect" stroke, it's about being a great adapter. By understanding what green speed truly is and having a plan to adjust to it, you can take the guesswork out of putting and approach every green with a renewed sense of confidence.

Final Thoughts

In the end, green speed is a simple measure of putting-surface friction that dictates both a putt's distance and its break. Learning to judge it on the practice green before you play and adjusting the length of your stroke - not the tempo - is the foundation for solid putting on any course, on any day.

Figuring out a day's green speed in just a few minutes on the practice green can still be a challenge. We built Caddie AI to act as that expert voice to help you process it all. You can ask what to focus on during your pre-round warmup to dial in your speed, or get a second opinion on that treacherous downhill putt. Our goal is to give you course management tools and the confidence that come with having a tour-level caddie right in your pocket.