Long-term Review: Suunto M-3G Global Compass || Fast, adjustable & ultralight

In a trail-less wilderness like Grand Staircase-Escalante, I use my magnetic compass extensively.

In a trail-less wilderness like Grand Staircase-Escalante, I use my magnetic compass extensively.

If I only occasionally needed to “find north” to roughly orient a map or to follow a short bearing, a basic magnetic compass like the Silva Starter would be sufficient.

But I rely more heavily on my compass than that, since I often backpack in low-use areas where signage is unreliable and trails can be intermittent, as well as off-trail. The compass is a core component of my navigation toolkit, best used in partnership with my topographic maps and GPS sport watch (a combined timepiece, altimeter, and auto dead-reckoner).

For several years I have preferred the Suunto M-3G Global Compass, which is a premium model that I would recommend to other heavy compass users, current or aspiring.

Long-term Review: Suunto M-3G Global Compass

For my purposes the M-3G Global hits the sweetspot. Key specs:

  • Adjustable declination
  • No sighting mirror
  • Global needle
  • 1.6 ounces (45 grams), with stock lanyard

The M-3G’s price is high but attainable, and I’d encourage readers to think about it like a premium sleeping bag: buy it now, take care of it, and replace it in 10 or 20 years.


Feature set

A skilled photographer with a crappy camera will take better photos than an ametueur with a pro-level model. The same is true about navigators and compasses. A premium compass is not necessary to navigate expertly, but it is more convenient, efficient, and pleasant to use.

Adjustable declination

Without this feature, it is necessary to manually adjust for declination, or the angular difference between true north and magnetic north. The adjustable declination feature minimizes errors, especially when fatigued.

No sighting mirror

A sighting mirror is primarily designed to improve accuracy when finding or transferring a bearing in the field, because you don’t have to shift your eyes as much. Incidentally, it also protects the top of the compass.

Personally, I’m unsold by these supposed advantages, and do not believe that a sighting mirror is worth the added weight or expense. Without one, I can be equally accurate with negligible inconvenience, and I can protect the compass simply in how I store it. The M-3G remains ultralight, at 1.6 ounces with the stock lanyard.

Global Needle

The standout feature of the M-3G is its global needle. Even if you are not planning to backpack in Antarctica or Ellesmere Island, where most magnetic compasses go haywire, you will still benefit.

The compass need not be perfectly level for the global needle to rotate. In fact, it can be pitched at a 20-degree angle, and the global needle will still work flawlessly. This makes the M-3G very responsive. Finding and transferring bearings in the field is slower and more tedious with compasses that do not have a global needle.

Watch this video to see the difference:

Clinometer

One important variable in avalanche risk is slope angle. The M-3G has a built-in clinometer so that it can be accurately estimated.

Durability

In 2013 Suunto sent me ten M-3G compasses for loaning out on my guided trips. They were used on about 40 trips, and normally each one of them was checked out.

My remaining seven show signs of wear, but they have fared well overall. At some point most of them were dropped in fine Utah sand, subjected to a night-long downpour outside a tent, stepped or slept on, or jammed into a pocket with hard and sharp objects. They are all still operable: no bubbles in bezels, fairly smooth operation (with some help from a dab of olive oil after desert trips), and legible imprinting.

My demo compasses have fared well over the course of about 40 guided trips.

My demo compasses have fared well over the course of about 40 guided trips.

Alternative recommendations

For occasional and basic use, an inexpensive baseplate compass is sufficient. It will not feature adjustable declination or a global needle. Consider the:

For more extensive use but without the price tag of the M-3G, select a compass with adjustable declination but without a global needle. Consider the:

Good, better, best. The Silva Starter (left) is sufficient for occasional and basic use. The Suunto M3-G (right) is best for extensive navigation. And the Suunto M3-D Leader (center, old version) is a more budget-friendly alternative than the M3-G but more advanced than the Starter.

Good, better, best. The Silva Starter (left, old version) is sufficient for occasional and basic use. The Suunto M-3G (right) is best for extensive navigation. And the Suunto M-2 (center, similar to the M-3D Leader) is a more budget-friendly alternative than the M-3G but more advanced than the Starter.

How to use your compass

If you are not yet proficient in operating a compass, check out these posts and watch these videos:

What compass do you own and what are your thoughts? If you are in the market, what questions do you have about them?


Disclosure. I strive to offer field-tested and trustworthy information, insights, and advice. I have no financial affiliations with or interests in any brands or products, and I do not publish sponsored content

This website is supported by affiliate marketing, whereby for referral traffic I receive a small commission from select vendors like Amazon or REI, at no cost to the reader.

Posted in , on November 28, 2016
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33 Comments

  1. Bob S. on November 28, 2016 at 5:42 pm

    I’ve been using a Silva Ranger Ultra for 10+ years. It’s fine for on-trail use but over the years the dial developed some slop so it’s probably 1 to 2 degrees off.

    I prefer to leave the adjustable declination set to zero and do the math rather than adjust the declination on the compass. I guess whatever technique works best for you is the one to use.

    Although map and compass skills are essential for anyone venturing into the great outdoors, I’m pretty sure the Donner Party would have preferred to use a GPS…

  2. Walter Underwood on November 28, 2016 at 7:10 pm

    Back in the 1970’s, my dad had a Silva Ranger with a mirror. We didn’t need the extra precision, but it sure was handy for figuring out how much his beard had grown out or for getting a look at the hot spot on the bottom of the big toe. Of course, it was a few days into each of three trips before we remembered we had a mirror. Sigh.

    So I still carry a compass with a mirror, because it is kinda useful on the compass and very useful for other things.

    Try carrying a compass with a mirror, then remembering that you have a mirror in your pack. You might like it.

    But the Suunto M-3D is a great compass.

    • Andrew Skurka on November 28, 2016 at 8:04 pm

      Love comments that start with, “Back in the 1970’s…”

      I’m surprised at how often I have felt like I needed a compass. And when you really need one, you really do. You can take a selfie of yourself, but the on-camera resolution is usually not good enough to see what is going on.

  3. spelt on November 29, 2016 at 7:02 am

    I use an M-2. It has a bubble after only a few years, but it still works.

    • Alex on November 29, 2016 at 12:15 pm

      After 7 years of use my M-2 developed a bubble tooand has now grown to the point where it impedes the rotation of the needle. I still have it to for my 6 year old son to learn on.

      This summer I picked up a M-3 D on sale and agree that it’s a good compass. I appreciate the longer baseplate over the M-2 and the bezel rotates smoothly with no wobble. The adjustable declination mechanism works fine, but can be a bit hard to set accurately due to the tiny 2 degrees tick marks-same on the M-2.

      • Andrew Skurka on November 29, 2016 at 1:22 pm

        Want to clarify: Do you have the M-3D or the M-3G? They are on the same chassis, but the needle action is so different that they shoukd not be confused.

        • Richard George on September 29, 2020 at 7:52 am

          Andrew:

          I purchased and enjoyed your book.

          On the REI site, there are several negative comments about the Global version getting bubbles. Has the quality changed on the M-3G? I don’t mind spending $80 for a good compass that has declination adjustment and can be used slightly tilted, but I don’t want to get a bubble right away

  4. Alex on November 29, 2016 at 5:44 pm

    I have the M-3 D. I checked out the G (Global) and was impressed with how quickly the needle righted itself, but just couldn’t justify the price.

  5. Ryan on June 23, 2017 at 6:58 am

    What is your opinion of the Brunton TruArc 5 Compass? https://www.rei.com/product/877063/brunton-truarc-5-compass
    It has adjustable declination and a global needle, but is a quarter of the price of the Suunto M-3G.

    Also, I’m not sure the Silva Explorer 203 has adjustable declination. From the looks of things, you can’t put “red in the shed” you have to put “red on the appropriate point of the declination scale”; I think you have to get the Silva Explorer Pro for a few dollars more to get the “gear driven” declination adjustment.

    Thanks!

    • Andrew Skurka on June 23, 2017 at 10:08 am

      I’ve looked at the TruArc 5 before but I’ve never seen it in-person. So no comment. If the declination adjustment and global needle are as functional and reliable as the Suunto, then it would seem like a good deal.

    • Christoph on August 18, 2019 at 1:25 pm

      I have a Brunton Adventure Racing Compass that I only used for one 7 day trip a few years ago. Just pulled it out of storage and the needle is barely moving, that is I can move it at least 90 degrees without the needle reacting. If I bump it, it still points north, but I definitely need a new compass, which is why I’m here. I would never buy Brunton again.

  6. Jeff on April 21, 2018 at 10:42 am

    I’ve been looking at the M3 Global and it looks like the current model is primarily metric. The scale on the front edge is a 1:24,000 for km; with only one “miles” scale inside the body of the baseplate. Is the metric thing a big deal? I found an ebay seller that has a few of the imperial versions of the global, where the scales look exactly like the photos in this article. I was wondering if I should snap up one of the imperial models while their still available, or if the current metric version is workable.

    Thanks.

    • Andrew Skurka on April 21, 2018 at 11:51 am

      Suunto makes an imperial and metric version. If you’re mostly or entirely in the US and have imperial maps, it would be useful to have the imperial version, although it’s not a deal-breaker to quickly convert the distance.

      I think the linked Amazon product is imperial, and right now $52.

  7. Jeremy on May 18, 2018 at 12:29 pm

    I love the great outdoors and there is nothing I love more than being out in the wilderness were it ha been untouched by man in decades. With that said I have had to teach myself alot of the skills necesary to survive on my own. But, I know I am lacking in the very valuable skill of using a compass properly, and truly orienting myself. Since my resources are limited, do you have any suggestions, or websited that could help me develop this skill?

  8. Greg Kinman on October 10, 2018 at 9:13 pm

    Hey Andrew – what’s the additional smaller black needle for? I’ve noticed it seems to follow gravity more than magnetism…

  9. peter vacco on December 1, 2019 at 9:26 pm

    the Suunto M3-G is an amazing piece of gear, with a more complex failure mode than might be apparent. all four of mine have developed the dreaded bubble after approx two years of ownership. the capsules do not seem to leak, and i suspect the fluid migrates thru the plastic. the newest one now shows a bubble above 5k feet. the older units have bubbles at sea level. arctic weather (mostly sea ice, so at sea level) is cold enough to cause the bubbles to disappear/contract, which would be great, if not for the reality that as the bubbles go back to a fluid state, it reduces the volume in the capsule, causing the top and bottom to come closer together and lock the needle in place. thusly, one needs to keep the compass next-to-skin-warm to maintain functionality. loss of fluid volume due to low temperature is also probably a contributing factor, but .. no warm bubble = works in the cold. bottom line, the device works so much better than anything else, that i buy a new unit every couple of years.

  10. Grant on March 25, 2020 at 8:21 am

    A comment about the book in your video — a week ago today I was at a small mountain in New Mexico. Who do I meet at the trail-head? Gerry and Jennifer Roach. They are still out there — climbing everything.

    It’s quite a gift to meet heroes. Giving thanks for that. Whats next? I’ll look for you today.

  11. Patrick Ploenzke on May 18, 2020 at 8:39 pm

    I found one on Amazon for less… famous last words.

    I just got my new Suunto and took it out for a test. I noticed immediately that the needle was getting hung up and was sluggish. I further examined the needle movement with a magnet and discovered the needle is getting caught on the clinometer. I went to the REI site to look for some reviews and see if anyone else has had a similar problem. No luck. But, I noticed the picture in the REI listing was different than my compass. The Suunto M-3g compass on their site has what appears to be a stamped metal needle. Mine appears to be a very thin plastic with stickers on it. Also, I noticed that the center of the needle is reddish on the REI one an mine is not.

    I knew you recommended these compasses and thought I better look at the ones you have. Yours are the same as pictured on the REI site. I then went to the Suunto site and found that it is the same as mine having the plastic needle. This was somewhat comforting. I was beginning to think I got a knock off.

    Did Suunto change the needle and I just got a defective one?

  12. Noah Bradley on June 11, 2020 at 2:05 pm

    Suunto seems to have since changed their M-3 G compass to an inferior version (the logo is in the middle of the capsule). Any thoughts on the new design?

    • Manolo "Manny" Mauriz on June 12, 2020 at 12:55 pm

      Noah, I recently purchased a new M-3G with the red/black plastic version of the global needle, and compared to several MC-2 globals I have with the original orange/white metal needle, this newer one does seem to be inferior. I haven’t had the needle get stuck yet, but it does seem to not sit level, as the red end appears to dip down a bit. My orange/white needled MC-2’s have the needle sitting level when resting the compass on a desk. I thought the main point of Suunto’s global needle was that it stayed level. Also, the degree numbers on the bezel are really small and about half the size of the numbers on my older Swedish made Silva Ranger 15T compasses. It’s funny, but I spend money to try out new compasses and end up going back to my trusty Silva Rangers…(the older ones, not the new ones made in Asia).

      • Walter Underwood on June 12, 2020 at 1:08 pm

        I would not expect the global needle to be level. The needle is attracted to the actual location of the north pole, which is through the earth, below the horizon. In the northern hemisphere, a needle must be weighted slightly heavier on the south end in order to sit level. When an compass is used in the southern hemisphere, it will need even more weight in order to sit level. A global compass is probably weighted to be level at the equator.

        Sketching this out really helps, by the way.

  13. Manolo "Manny" Mauriz on June 12, 2020 at 1:02 pm

    Mr. Skurka’s review of the M-3G is the best one I have read so far and if I could find one like the one pictured in this review with the orange/white needle in decent condition, I would buy it in a heart beat. Again, thank you Mr. Skurka for your thorough and informative review.

    • Patrick Ploenzke on June 14, 2020 at 12:25 pm

      I ordered from Amazon first. Suunto was the seller and the M-3G that I got was definitely defective. The needle hung up on the inclinometer and it was not accurate. I ordered from REI hoping to get an older version. Same exact compass thou. However, it works perfectly. Needle movement settles in instantly unlike my previous one. I wonder now if it had any liquid in it. I took mine out on a local orienteering course and with the updates it seems to still be a good product.

  14. Tony S on June 14, 2020 at 10:11 am

    Reading a bunch of reviews, many have remarked that the new version/design of the Suunto M-3G compass is not good. Complaints have been generally about poor quality, lost of certain features, etc. Can you please comment on whether the Suunto M-3G newest version in 2020 is still a good buy or should we look at another compass? Thank you.

  15. Manolo “Manny” Mauriz on June 14, 2020 at 2:22 pm

    Walter, you are correct in your statements regarding the hemisphere balancing of normal, conventional compass needles, however, this does not apply to Suunto’s global needle design. From everything I’ve researched regarding this design, which Suunto borrowed from Recta of Switzerland, the magnetized portion is not the needle, but the central hub it is mounted to. This ingenious design allows the hub to dip according to the earth’s magnetic fields while allowing the hinged needle to remain level with the help from the tiny upturned tabs at the ends of the needle. This is how they achieve the “global” ability since it’s not balanced to any specific hemisphere. IMHO, the original global needle design of the earlier Suuntos works better than this latest one.

  16. Manolo "Manny" Mauriz on June 15, 2020 at 12:09 pm

    Tony S., I would say go ahead and get the Suunto M-3 Global, even if it’s the latest version with the plastic needle. Suunto makes excellent compasses (and dive computers) and are very well-respected world wide. Just be sure to purchase it from a reputable source which will honor a return or exchange in case it is defective. I’m a bit of a compass nerd/collector and am probably nitpicking a bit with my complaint of the needle not resting perfectly level, but in all fairness, my new M-3G works just fine. As far as another option to consider in a quality name-brand baseplate compass, Silva makes several models of baseplate style compasses and some have a Global needle. I don’t like that the new Silva’s are made in China, but Silva is a very well known name, are designed in Sweden and I’m sure they stand behind their products. Just my 2 cents…

  17. Jon Freivald on July 19, 2020 at 6:06 pm

    Silva Ranger Global is the one I carry. It’s not adjustable for declination, but had a declination scale on it, so still no in-field calculation, I just have to remember what it is for where I am. When I’m going in to a new area, I will stick a piece of masking tape on the baseplate with the declination for the area noted on it.

  18. Ronton on February 11, 2021 at 2:51 am

    Agree, most common route-finding cases involving a compass don’t need a mirror. Precision of mirror useful, under certain circumstances, for triangulation of one’s position, or that of a target. GPS, if working, alleviates but does not obviate the first, helps with the second. A mirror use case is boat on large water vs. shore features or other boats. Another occasional use is precise following of bearing in low-feedback environments, white-out on snow, fog on water – if no GPS.

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