To ensure your new carabiner is strong enough to use rock climbing, make sure it is CE and/or UIAA certified from a known climbing manufacturer. That’s it!

Keep reading to dive deeper into what these ratings are, where they come from, and how they are related to your everyday climbing, both indoors and out. Understanding how carabiners are certified helps ensure you know how, where, and why you can expect carabiners to work. Knowing how strong carabiners are is a great peace of mind when you’re belaying someone, hanging from rope, or about to take that fall.

Identifying a Certified Carabiner

On the spine of every certified carabiner there will be a CE and/or UIAA icons. They will either look printed (laser etched) or forged into the body of the carabiner.

CarabinerMarkings 1

Note: UIAA certifications are optional for manufacturers. CE certifications are mandatory to sell products in Europe. The number after the CE marking is the 4-digit code of the CE Lab who certified the product – this is why you’ll see different numbers on different brands.

A carabiner is not stronger/weaker if it only has one rating. CE certification standards are often based on UIAA recommendations.

Minimum UIAA Carabiner Strengths

Carabiners rated for climbing have minimum strength requirements to ensure the gear will not break when used properly. Climbing carabiners are rated in 3 orientations:

Major Axis Minimum Rating

This is the carabiner loaded from end to end. It is the strongest orientation and the main way carabiners are designed to be loaded.

  • All carabiner shapes except ovals: 20 kN
  • Oval carabiners: 18 kN
Major Axis Carabiner Strength

Open Gate Minimum Ratings

Being loaded while the gate is open is a rare occurrence. It could happen while climbing when a carabiner rubs against the rock or moves across an uneven surface. A carabiner can also open slightly during a fall as it is suddenly loaded. The dispersion of this energy causes vibration which can make the gate move enough to open (also called “gate flutter“). A weak gate closure (due to a poor/failing spring, an over-stressed wire, or dirt clogging the closure mechanism) could also leave the gate slightly ajar.

  • D, Offset D carabiners: 7 kN
  • HMS / Pear (belay carabiner) shapes: 6 kN
  • Oval carabiners: 5 kN
Carabiner Strengths2 2

Minor Axis Minimum Ratings

Carabiners are not intended to be loaded along the minor axis (cross-loaded), but it’s possible for a carabiner to unintentionally rotate during use, particularly during belay. Of all accidental misuses of a carabiner, cross-loading is the most frequent suspect, which is why there is a rating for it.

  • All carabiner shapes: 7 kN

Note: Generally wire gates are stronger than solid gates in this orientation. During the test, the wire gate bends, absorbing some of the force, as compared to a less pliable solid gate.

Carabiner Strengths1 3

The Testing Process

UIAA and CE testing is done by certified third party labs around the world. Brands submit climbing gear to these labs to ensure they meet or exceed the standard, and are awarded the UIAA or CE mark, or both if they pay for each.

As we mentioned above, CE certifications are required for all products sold in the EU. Because the CE is a multinational body, it does not have expertise in any niche topic, and instead relies on established industry standards like the UIAA to create recommendations and requirements. CE standards are known as ‘Euro Norms’ (EN certifications) and are generally considered to be identical to the UIAA methods. The UIAA committee is comprised of multiple professionals from the climbing industry.

In practice this is what happens: The UIAA makes the standard based on industry knowledge, the CE body reviews it and creates an EN standard based on UIAA recommendation, and independent labs are paid by brands to test to the standard, which is then applied to the climbing gear. If a brand wishes to sell a product in the EU, it must be tested specifically to the CE EN version. Once certified they can legally apply the CE marking to the product as it complies with the EN standard.

In the case of carabiners, the labs test using UIAA 121 which informs CE EN 12275 (see below). To learn more about how the UIAA and CE EN certifications work you can check out this post where we dive into the nuances of each certifying body.

Now let’s get into the details of the UIAA test:

UIAA 121 Carabiner strength test
This excerpt from the UIAA 121 and EN 12275 certification shows the tests that carabiners must pass in order to be certified. Full documentation is available on the UIAA website.

The full testing process is complicated and changes a bit based on the type of carabiner and its intended use. Each area and axis of the carabiner is pulled to failure, and must not break below the standard’s requirement.

The UIAA emphasizes that carabiners never break when tested with a free falling mass. Rather than simulating a fall, the certification uses static pull tests that massively exceed fall forces.

The UIAA has also stated that, “A real climbing fall has a maximum force of 5kN.” This is because a falling climber on dynamic rope is free to move laterally and induces less vibrations into the system than a static fall. The UIAA standard for climbing karabiners demands a static strength of more than 20kN, which is equivalent to holding a mass of over 2 tons before breaking. This is many times the force present in the worst conceivable fall in a climbing accident.

This excerpt comes from a full article that addresses dynamic versus static testing. You can click to read the PDF article in its entirety.

Carabiners Can Break In-Use (Extremely Rare)

While it is possible to break a carabiner while climbing, it only happens when the gear is not being used as intended.

In rare cases when carabiners have broken in-use, virtually all of them have broken when the nose was loaded as the nose is the weakest point of the carabiner. Since carabiners are not designed or intended to hold falls on the nose (and it is rare that this happens), there is no certified rating for the nose.

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Black Diamond did a study on nose-hooked carabiners and found they can break at less than 10% their normal strength. (Image courtesy Black Diamond)

A carabiner may break if…

  • The nose gets caught on a bolt hanger or piece of gear and then loaded (see photo above). Typically this happens when a notched nose carabiner gets hooked on a bolt hanger. Black Diamond wrote a Quality Control post about this situation and concluded that the nose of a carabiner may fail at less than 10% of its rated closed gate strength (<2 kN / 227 kg), forces achievable in a bounce test.
  • The carabiner rotates and then becomes cross-loaded. To learn more you can read a 2013 accident report (2023 update: the photos no longer appear but the story is still there) where a keylock carabiner broke because a fall was taken and the carabiner was not weighted on the major axis. The climbers take-away points included, “double-check your draws to make sure they are hanging properly and not snagged or twisted.”

It is only slightly unfortunate that nose strength is not a rated part of the carabiner. Yes, it’s the weakest area. That said, a carabiner should never be loaded in this orientation during proper use and it rarely happens (much less than cross-loading and gate flutter). To test and certify the strength of the carabiners nose, it would require additional time and money, making gear more expensive without adding a substantial safety benefit.

The main reason WeighMyRack doesn’t filter on carabiner strengths is because it doesn’t make a noticeable difference while climbing. Yes, carabiners with higher strength ratings will be stronger, but in normal use even the weakest rated carabiner will perform admirably.

It’s not the strength ratings that will determine the breaking point of your climbing-rated carabiner, it’s how you use it.

Gear is Strong. It Can Take A Lot of Abuse

There are tons of gear videos online showing huge whippers, and these are just the falls caught on video. Rock & Ice, a well-regarded climbing magazine and website (RIP 2020) used to dedicate a whole section of their website to “Weekend Whippers” and would make a yearly compilation of the worst falls, almost all over 40 feet.

These are not average scenarios but each time the gear performs as intended during seemingly catastrophic falls.

Strength Rating Is Generally Unhelpful

Since all carabiners are rated to be super strong from a normal climbing perspective, you’re fine with the minimum rating or highest rating. A higher strength rating doesn’t mean it’s stronger, as it’s the use case that really matters.

Buying Tips Instead of Strength Rating

  • Only choose carabiners that are certified for rock climbing (CE / UIAA). Carabiners/hardware that are not certified for climbing fail at low forces.
  • Always buy gear from known climbing manufacturers. There have been cases of cheap overseas knockoffs that may exhibit a slightly narrower CE logo that is nearly identical to the official CE rating (for “European Conformity”) but the knockoff actually means “China Export.” There have also also been folks looking to jump on the exploding climbing market who are importing unbranded gear to sell cheaply online. Neither of these cases can be trusted to be officially CE / UIAA certified.
  • Look at the nose of each carabiner: clean nose angles, keylock carabiners, and shrouded noses will all reduce the ability for the carabiner to snag and become loaded in an unintended orientation.
  • If you’re worried about gate flutter, use wire gate carabiners on the rope-end of your quickdraws. The lighter wire gate is also less prone to whiplash that may cause a gate to shutter.
  • Most climbers find full-size carabiners are easier to hold and clip, reducing the chances of falling on a snagged nose, so it can be helpful to avoid the smallest carabiner models.
  • You may also want to use full-size carabiners because your brain intuitively believes they are stronger (even if that’s not actually correct). Nothing is worse than questioning your gear, and mini-carabiners or lightweight hollowed out carabiners can look questionable even though they can be just as strong.

After you buy

  • It’s important to inspect and clean carabiners to ensure their longevity. A sticky gate has a much higher chance to cause serious issues. If the carabiner gate feels weak or looses it’s ‘snap’, and it doesn’t come back after cleaning, retire it.

While you climb (Tips compiled from accident reports)

  • When extending trad draws, remove any loops that develop.
  • Rack long slings fully extended and fix the lower carabiners to prevent cross-loading.
  • Use locking carabiners on critical pieces.
  • Avoid kicking or shifting your draws as you climb past them.

Bottom Line

There is no direct answer to, “What is the most ideal strength rating?” or “What is the strongest carabiner?” All things being equal, higher strength ratings are better. However, the design of a carabiner’s nose (angle, type, shroud), and using the gear correctly (orientated in an optimal direction) makes a bigger impact on the safety of a carabiner versus comparing the individual strength numbers. Ultimately, any CE / UIAA rated carabiner coming from a known climbing manufacturer is safe to climb on.

This post was originally posted in March of 2015 and was inspired by a question we received asking, “What would be a good guide for a safe minimum strength numbers regarding the ratings?” In addition, Mike Kann helped beef up our post by offering some great caveats around open gate strength, statistics, and knockoffs.

If you have gear questions, feel free to reach out publicly via the comments below, or privately by using our contact form.

Alison Dennis

Alison Dennis

Alison (she/her) runs WeighMyRack from her 17' travel trailer. She is currently touring the US and would love if you contacted her to meet up to talk about climbing, climbing gear, or if you have any fun and/or ridiculous adventure in mind.

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We’re @weighmyrack


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