Rangefinders and 'Plays Like' Distances: What They Measure and What They Miss

A rangefinder is one of the most useful things a golfer can carry. It replaces guesswork and yardage markers with a precise number for every shot. But that number is the distance to the target, not how far the shot will actually play, and on a hot afternoon in the desert or on a mountain course, the two can differ by more than a club. This guide explains what rangefinders measure, what their "slope" and "plays like" modes add, what the rules allow, and what almost every device still leaves out.

Two Kinds of Rangefinder

Laser rangefinders are small monocular devices. You look through the eyepiece, aim at the flag or any other target, and press a button: the device fires an invisible laser pulse and times its reflection to measure the straight-line distance, usually to within about a yard. Most have 6x or 7x magnification, and many vibrate or show a symbol when they lock onto the flagstick rather than the trees behind it.

GPS devices, including handheld units, golf watches and phone apps, work differently. They know your position from satellites and compare it with a map of the course, so they can show the distance to the front, middle and back of the green, and to hazards you can't see, without aiming at anything. Their accuracy depends on your position fix and on how well the course is mapped, and they measure to fixed points on the green rather than to where the flag is today.

Many golfers use both: GPS for the overall picture of a hole, and a laser for the exact number to the flag.

What 'Slope' Adds

Distance is measured in a straight line, but a shot that climbs 30 feet to an elevated green plays longer than the same distance on the flat, and a downhill shot plays shorter. A rangefinder's slope mode measures the angle to the target and shows an adjusted "plays like" distance that accounts for that elevation change.

A few premium lasers go further. Bushnell, for example, describes its "Slope with Elements" feature on the Pro X3+ as adding temperature and altitude to its slope calculation.

What Most Devices Still Leave Out

The biggest effect missing from most rangefinders is the air. A golf ball flies farther in thin air, and air gets thinner with altitude, with heat and, slightly, with humidity. Our carry model, calibrated to golf's rules of thumb of about 2% more carry per 1,000 feet of altitude, estimates how far a 7-iron that carries 150 yards at sea level on a 70°F day would carry on an average afternoon in some of the places we cover:

• Yuma, January: about 150 yards.
• Phoenix, January: about 152 yards.
• Phoenix, July: about 157 yards.
• Las Vegas, July: about 160 yards.
• Reno, January: about 158 yards.
• Reno or Sedona, July: about 165 yards.
• Flagstaff, July: about 170 yards.

A standard slope rangefinder shows the same number in all of those places. The difference between a winter round in Yuma and a summer round in Flagstaff is 20 yards on a 7-iron, roughly two clubs.

Other factors that no rangefinder captures:

• Wind, which depends on the direction of each shot and changes by the minute.
• Your lie, from a tight fairway lie to thick rough or a downhill stance.
• Firmness and roll, which matter more for how far the ball ends up than how far it carries.

What the Rules of Golf Allow

Under Rule 4.3a of the Rules of Golf, you may use a device to get information on distance or direction. But during a round, the device must not:

• measure elevation changes, which rules out slope mode, or
• interpret distance information, for example by recommending a club.

A competition committee can also ban distance-measuring devices altogether with a Local Rule. In practice, slope and "plays like" modes are fine for practice and friendly games, but they must be switched off whenever you play under the Rules of Golf, as in any competition. Many slope rangefinders have a physical switch or indicator for this; Bushnell's Pro X3+, for example, has a locking slope switch designed to prevent it from being turned on by accident during tournament play. A breach of Rule 4.3 costs the general penalty the first time, and disqualification the second time in the same round.

What to Look For

If you are choosing a rangefinder, these are the features worth comparing:

• Laser, GPS or both: a laser gives the exact distance to the flag; GPS gives the whole hole at a glance. Some golfers pair a laser with a golf watch or app.
• Slope with a clear off switch: useful for casual rounds, but make sure it is easy to turn off, and easy to check that it is off, if you play in competitions.
• Flag lock: a vibration or on-screen confirmation that you have hit the flag rather than the background.
• Display and optics: magnification and how readable the display is in bright light, which matters in the desert sun.
• Size, battery and mounting: a magnetic mount for the cart and a battery that lasts a season are small conveniences that add up.

How TeeGauge Fits In

A rangefinder tells you the distance; the air tells you how far your clubs will fly. Each of our course pages estimates carry for every tee time, from the course's elevation and the forecast temperature and humidity, so you can check before your round how much farther, or shorter, your clubs are likely to fly that day. Combined with your rangefinder's distance, it gives you a better starting point for choosing a club.

Find your course on our Arizona and Nevada golf weather pages. For more on how altitude changes the game, see our guides to golf in Reno and golf in Sedona, or Course Rating and Slope Rating Explained, which is about a different kind of slope.

Sources: R&A, Distance-measuring devices (Rule 4.3a); Bushnell Golf, Pro X3+ Link; carry estimates from TeeGauge's carry model, using NOAA 1991–2020 climate normals.

Photo: a smartwatch showing golf GPS distances, by Pebble Technology, licensed under CC BY-SA 1.0, via Wikimedia Commons. Resized from the original.