Golf GPS devices have become something many of us rely on for almost every shot on the golf course. But just how accurate are they?
I decided to find out for myself.
The idea came after a conversation with the PGA Professional at my home golf course. I had asked him to read my review of the Garmin Approach S40 golf watch, and he asked me a very simple question:
“Have you actually checked how accurate it is against other devices?”
I hadn’t.
That got me thinking. Rather than simply accepting the distances displayed on a GPS watch, I decided to test them properly.
For the test, I used three GPS devices, two laser rangefinders and a 50-metre surveyor’s tape. I then headed out onto my home golf course in Sheffield to see how the different devices compared.
How Does SkyCaddie Work?
SkyCaddie is produced by SkyGolf, and its approach to mapping golf courses is particularly interesting.
Rather than relying entirely on aerial imagery, SkyCaddie says its professional course mappers physically walk golf courses using survey-grade GPS equipment. The collected information is then checked before being added to its course database.
That sounds impressive, but I wanted to see how the distances compared with the other devices in a real-world test.
Who Is Garmin?
Garmin is one of the best-known manufacturers of GPS and navigation products and has produced golf GPS watches and handheld devices for many years.
For this test, I was particularly interested in comparing readings from the Garmin Approach S10 and Garmin Approach S40.
How I Tested the Golf GPS Devices
It was a Saturday in December and torrential rain had closed the golf course.
So what did I decide to do?
Spend my Saturday walking around the golf course carrying a surveyor’s tape, three GPS devices and two laser rangefinders.
My wife gave me a very bemused look as I left the house. But if you love golf, sometimes you do these things!
I decided to measure 10 holes at my home course in Sheffield. They were the holes closest to the clubhouse, and with more heavy rain approaching, I wasn’t going to risk attempting all 18.
The plan was to establish an accurate position using the 50-metre tape — equivalent to approximately 54.7 yards — and then compare the readings produced by the GPS devices and laser rangefinders.
Are Golf Laser Rangefinders Accurate?
Before judging the GPS devices, I needed to know that my reference measurements were accurate.
I tested two laser rangefinders — a Bushnell Tour V5 and a Nikon 350 — from a measured distance of 50 metres (54.7 yards).
The results were impressive.
Across all 10 holes, the laser rangefinders were consistently accurate to around one yard. The Nikon and Bushnell were also within approximately half a yard of each other on every hole.
That gave me confidence that the lasers provided a reliable benchmark against which I could compare the GPS devices.
Are Golf GPS Devices Accurate?
The short answer is yes — but with some important limitations.
Overall, I was impressed with the accuracy of the GPS devices. The SkyCaddie generally performed slightly better than the Garmin watches during my testing.
However, I did find some surprising differences.
On several occasions, the Garmin S10 and S40 displayed different distances despite being used from exactly the same location.
On one hole, the difference was more than 12 yards.
That’s significant. Depending on the golfer and the shot, 12 yards could easily mean selecting a completely different club.
Before we’d even started the measured tests, I noticed another interesting example. Standing towards the back of the first tee, there was a difference of around 30 yards between some of the Garmin and SkyCaddie readings.
The 50-Metre Distance Test
On each of the 10 holes, I positioned my Eat Sleep Golf Repeat marker at the front of the green.
From that point, I pegged a surveyor’s tape into the ground and measured exactly 50 metres — approximately 54.7 yards.
I placed a tee peg or golf ball at the measured position and then used the laser rangefinders to confirm the distance.
The lasers were excellent.
The GPS watches were reasonably accurate and certainly capable of providing useful distances for most golfers, but they weren’t perfect.
During the test, the Garmin S40 generally performed better than the S10.
What surprised me most was that two GPS watches from the same manufacturer could sometimes give noticeably different readings from exactly the same position.
On one par-three hole, there appeared to be an issue with the location Garmin was using for the front of the green. The resulting distance was approximately 10 yards out.
The centre-of-green reading was more accurate, but if you were attacking a front pin, a 10-yard discrepancy could leave you well short.
The 150-Yard Marker Test
Next, I compared the GPS devices from the 150-yard markers positioned around the golf course.
There is an obvious limitation with this test: we first have to assume that the golf club’s 150-yard markers have been positioned accurately.
Nevertheless, the comparison produced some interesting results.
There were differences of around five or six yards between some of the Garmin and SkyCaddie readings.
For a higher-handicap golfer, that level of variation probably isn’t going to make a significant difference. For a lower-handicap golfer trying to control approach shots more precisely, five or six yards starts to become much more important.
What surprised me again was the variation between the Garmin S10 and S40 themselves.
On some holes there was around a three-yard difference between the two Garmin watches, despite both devices being made by the same manufacturer.
On one hole, the S40 differed from the SkyCaddie by around nine yards, while there was an even larger difference compared with the S10.
Centre-of-Green Test
I also compared the devices using measurements taken 50 metres (54.7 yards) from the centre of the green.
Again, the results followed a similar pattern.
There were occasions when the difference was around seven yards.
From a distance of less than 80 yards, I think that’s too large a variation for a better golfer to completely trust when trying to hit a precise yardage.
There were also noticeable differences between Garmin’s own devices, including one test where the two Garmin watches differed by around seven yards.
Verdict: Can You Trust a Golf GPS?
The Garmin Approach S40 used during this test was my own golf watch, and I’ve been very happy with it.
The test didn’t make me want to stop using it.
What it did do was reinforce why I also carry a laser rangefinder.
If I’m playing a Saturday medal or another important competition, I’ll generally use my laser alongside my GPS watch when I need an exact distance.
For a casual round or friendly game, I think a GPS watch is perfectly adequate for most golfers.
GPS devices are particularly useful when you can’t see the green — perhaps on a dog-leg or when playing to a hidden green. In those situations, having the distance available immediately on your wrist is extremely useful.
Of the GPS devices I tested, I found the SkyCaddie SX500 generally more accurate than the Garmin watches. However, I personally found the handheld unit quite large.
SkyCaddie also offers wearable devices for golfers who prefer a watch.
The biggest takeaway from my testing is that golf GPS devices are useful and generally accurate, but they shouldn’t necessarily be treated as perfect measurements.
For most golfers, the small variations I found won’t dramatically affect their game.
But if you want the most precise distance possible — particularly when attacking a pin — my preference is still a laser rangefinder.
I’ll continue using my Garmin S40 because I enjoy the convenience and the other features it provides. But when the exact yardage really matters, I’ll reach for the laser.
Hopefully this test gives you a better idea of what you can realistically expect from a golf GPS device.
