GPS Devices, GPS Lasers, Surveyor Tape

GPS Golf Devices – How Accurate Are They?

GPS Devices, GPS Lasers, Surveyor Tape

GPS Golf Devices - How Accurate are They?

In this article, we are going to test and check how accurate the Golf GPS devices are?
Which we all now depend on, for all of our shots on the golf course.

We decided to investigate how accurate my Garmin S40 Golf GPS device is. Recently I was having a chat with my PGA Professional, at my home golf course.

When I asked him to read one of my other reviews, the Garmin S40 Approach Golf Watch (In-Depth Review) he asked me, have I checked how accurate the Garmin device is, compared to other devices on the market? I had not at the time checked how accurate they are, and really did not think about it, but this got me thinking as to find out if these GPS Devices are accurate.

In this article we are going to test three GPS Devices; Garmin S40, Garmin S10, SkyCaddie SX500.  We will check these against a surveyors tape and two laser rangefinders, Bushnell V5 and Nikon 350.

The results are quite unbelievable, with some significant incorrect readings, that will surprise you.

Who is Sky Caddie?

Well, Sky Caddie is a product of SkyHawke Technologies, who operate under the SkyGolf Brand. SkyGolf is based in Mississippi.
Going forward in this article I will refer to SkyGolf as SkyCaddie because that is what us golfers know them as, and what the units are called.
So, SkyCaddie state their system is more accurate than the other GPS systems on the market, because;

How does SkyCaddie differ?

SkyCaddie visit every golf course they feature, they have a series of Mappers who turn up at each golf course and walk the golf course.

They state “All of our professional mappers use survey-grade GPS equipment, and the data they collect is triple checked for accuracy before it is added to our map library”.

Well SkyCaddie and GPS device makers, your statements are going to be checked again!

Granted at my home course, me testing several devices with lasers and a 50-metre surveyors’ tape, and we will see how we get on.

SkyCaddie also states that other GPS devices use second and third-generation maps which have been developed from aerial imagery.

They are stating that the system they use is accurate to 1 yard, so we will see how this unfolds.

Who is Garmin?

Garmin is a leading manufacturer and designer of navigation products, and they produce these navigation devices for many different market segments and golf being one.

GPS Device Testing

A Saturday in December, just found out I am not playing golf today, due to torrential rain and the golf course has been closed.

So, what did I decide to do?

Well, I thought today is the day to spend my Saturday walking the golf course with a surveyor’s tape, three GPS devices and two lasers.

When I left the house, my wife had a very bemused look on her face.

But if you love the game of golf then we do these stupid things!

I decided to measure 10 holes at my home golf course in Sheffield, these ten holes are the closest to the clubhouse, and it looked like heavy rain was on the way, I didn’t take the chance on the full 18.

The plan was to stake the front of the green so I could use the 50m tape (54.7 yards), this would then help me check the accuracy of the laser range finders so we could check the front of green markers on the

Garmin devices and against the SkyCaddie.

Are Golf Laser Rangefinders Accurate?

When I tested the two laser range finders, the Bushnell Tour V5 and the Nikon 350, I was so impressed how accurate they are, so are laser range finders accurate? 

The answer is yes they are very accurate.

After using them on ten holes at 50m or 54.7 yards, they were consistently accurate to 1 yard.

Both the Nikon and the Bushnell were accurate to half a yard against each other on every hole.

It was very impressive to test these.

Are Golf GPS Devices Accurate?

This is going to be a much longer explanation.
In the main, Golf GPS devices are quite accurate, and I was impressed in general with the accuracy of the Garmin devices, the SkyCaddie did perform marginally better.

However, I would have concerns with the SkyCaddie, if your golf course undertakes modifications like changing tee boxes or moving bunkers, I would wonder how long it would take for them to come back and walk the golf course again to produce the accurate data.

From my measurements, I did find several occasions when the Garmin golf GPS watches were presenting incorrect readings.

It was very strange that both Garmin devices, the S10 and S40 displayed different distances on many occasions.

In the image above you can see that on one occasion that variance was over 12 yards, which could be a club more or less in distance.

Before we even set off to start the measurements, we turned all the devices on and from the back of the first tee box you can see the difference of around 30 yards between the Garmin and Sky Caddie devices which is crazy.

See below image, SkyCaddie returned a 366 yard middle reading and the Garmin devices had 395 and 390 distances.

The 50m (54.7yards) Distance Check

On each of the 10 holes, I pushed my eat sleep golf repeat board into the front of the green.
From the board, I pegged the surveyor’s tape into the ground and walked the 50m away from the green.

When I hit the 50m mark I placed a tee peg or a golf ball next to the 50m (54.7 yards) mark and then used the lasers to check their accuracy, which as I mentioned earlier were fantastic.

Board in green indicating front of the green

You can see from the results that the GPS Watch devices were ok, they were not totally accurate but would provide the golfers with decent yardages.

Garmin claims that their devices are accurate to 3 yards, I found from this test the Garmin S40 was more accurate than the Garmin S10, with 4 failures (3 yards) over the 2 (yards) on the Garmin S40.

I was really surprised at the differences between their own devices.

From the data, you can see that there was a clear issue on the second hole, which is a par 3.

I would assume that Garmin has targeted the incorrect front of the green, which means the distance is 10 yards out.

GPS Watch Results

I must stress that the centre green-reading is more accurate, but If you are playing for a front pin, you could end up very short.

(if you are looking for hole 7 yardage, it is near the top of the article)

Hole 18 Yardage Check

150 Course (Yard) Marker Check

So, I decided to check the distances from the 150-yard marker, which the golf club has situated on each hole.

The first point I need to address is how accurate the club has placed these 150 discs.

The distances are quite close when we compare the three devices, there can be a 5-6 yard variance, between the Garmin and the SkyCaddie devices.

This will be quite acceptable to the higher handicap golfers because most would struggle to be that accurate, for the lower handicap golfers a 5-6 yard variance is just not close enough in my opinion.

150 Yard distances

It was also surprising having around a 3-yard variance between the S10 & S40 devices. From the same manufacturer, and the one hole where the S40 had a 9-yard variance to the SkyCaddie, and a further 12 yards to the Garmin S10.

150 yard distance

50 Metre (54.7 Yard) Centre of the Green Check

From the results which have been detailed, you can see the same sequence happening again.

From the 50M (54.7 yards) markers, and the 150-yard disc check, the variances are just too large for the better golfer to fully trust.

50 yard distances

There are often variances of 7 yards, which from less than 80 yards total is not close enough.
Some of the largest variances are between the Garmin own wearables, like the 18th hole displaying a 7-yard difference.


The Garmin S40 on test today is my golf watch, I have been happy with the performance and the features, but this test has highlighted to me why I also carry a laser rangefinder.

When I am playing a Saturday medal or other important competition, I will always use my laser in conjunction with my watch.

If you are a golfer who just plays for fun or having a friendly game of golf then I see no reason why just using a GPS device.

Using a GPS watch is fine, and they are useful when you cannot see the green like on a dog-leg or hidden green. Having your watch in these situations is great.

When using the SkyCaddie SX500 in this test and other times I have used one, I think the device is more accurate than the Garmin watch, but I didn’t like the size of the unit.

If like me you find the unit too large then SkyCaddie do a range of wearable watches which could suit you better.

You must be aware that SkyCaddie charges a yearly subscription for their service, which if they have to hire a team of people to physically walk each golf course, then I can understand why this charge is necessary.

Would I trust a SkyCaddie over a laser, probably not, but they do seem to be the more accurate alternative.

My final thought is, we are lucky to be able to have these devices support us while playing golf, and I for one will keep using my Garmin S40, it has a lot of other functions that I like which are not golf-related.

These devices are really helpful but if you want an accurate distance then, in my opinion, you got to use a laser rangefinder.

Hope you found this article helpful.