Understanding Carabiners: Your 101 Guide To Carabiners

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You’ve just started climbing and know you need some carabiners, but as you start looking, you notice many different sizes, features, and shapes.

All this has left you extremely overwhelmed, so what do you do?

Entering the world of climbing is no easy task, and it can often leave you feeling overwhelmed, but I’m hoping this article will help clear up any confusion and feeling out of your depth.

When it comes to understanding carabiners, you need to remember that different climbing tasks require different kinds of carabiners.

And to know which ones you will need, you need to understand their differences. For this, you need to think about five things:

  1. Gate Type
  2. Shape
  3. Weight
  4. Size
  5. Strength 

So, to help guide you on your journey to understanding carabiners, we will introduce you to everything you need to know.

Let’s get started:

Gate Types

rock climbing outdoor gear

For those who don’t know, when we’re talking about the gate, it’s used to describe the clip part of the carabiner.

There are four different gate types you’ll find:

  1. Lock Gate
  2. Straight Gate
  3. Bent Gate
  4. Wiregate   

#1 Lock Gate Carabiners 

As the name suggests, lock gate carabiners can be locked into a closed position, which prevents accidental openings.

To achieve the locking mechanism, it will use one of two methods:

  • Screw Lock: This requires the user to manually twist the sleeve on the gate to open or lock the carabiner.
  • Auto-Locking: The sleeve needs to be twisted and pulled down to open the gate; once released, it will automatically rotate back to a locking position.

Locking carabiners are safer and usually used for belaying or setting up anchors because they prevent them from being accidentally unclipped. And this can give you a lot more peace of mind regarding protection.

The downside is the locking mechanism makes it heavier than some of the other options on the list, so it’s best not to have too many in your climbing rack.


  • Provide more security 
  • They are usually stronger


  • They are heavier 
  • Harder to open

#2 Straight Gate Carabiners

Straight-gate carabiners are among the most common gates thanks to their strong, durable, and easy-to-use nature.

One of the great things about these carabiners is they can be used for various purposes, but they are most commonly found on quickdraws or for racking your gear (such as cams and stoppers).

As for the gate itself, it’s exactly what it says on the tin. It uses a straight pivot point to end with a spring load to snap it back into place.

Another great thing about straight gate carabiners is that some feature a keylock system. A keylock carabiner has a smooth notch which prevents the carabiner from catching on your gear loops. 

Of course, this will come at an extra cost, but it can definitely be worth the extra money.


  • It is a very strong and durable build
  • The keylock nose is a great feature
  • Easy to use


  • They can get snagged
  • Not as light as a wire gate

Bent Gate

Bent gates are much like their older cousin, straight gates, except these have a slightly concave shape, which makes it much easier to clip your rope into the carabiner.

Because of this concave shape these are most commonly found on the rope end of quickdraws.

But other than that, there isn’t much difference between a bent or straight gate carabiner. If it’s to clip to a rope, use a bent gate; if you’re clipping to your harness, use a straight gate.


  • Extremely durable
  • Makes it easy to clip to a rope
  • It can also feature the keylock system


  • Not the lightest carabiner 

Wiregate Carabiners

When you’re climbing multiple pitches, the weight of your rack becomes a serious talking point, which is why many people opt for wiregate carabiners.

Instead of having a hollow tube as the gate, wiregate carabiners use a loop of stainless steel, which helps decrease the overall weight. And thanks to the slim and lightweight design, it allows for a larger gate opening.

There are a few other reasons wire gate carabiners are so good:

For one, they are less likely to freeze in cold or wet weather, which can be a huge benefit depending on where you’re using them.

And finally, they are less prone to “Gate Lash,” which is where the gate opens due to the vibrations of falling.


  • Less likely to freeze such
  • It helps reduce gate lash
  • Lightweight 


  • It can be considered less durable

Carabiner Shape Types

Whether you’re staring online or standing in the shop, you will notice that carabiners have different shape types. And again, the shape you’ll need primarily depends on what you’re using it for.

And when it comes down to it, there are four shapes you’re going to run into:

  • D-shape
  • Asymmetric D-Shape
  • HMS
  • Oval Carabiners

In this section, I will walk you through what you can expect from them and the pros and cons surrounding them.

Let’s take a look:

D-Shaped Carabiners

D-shaped carabiners are excellent for most styles/types of climbing, which makes them a go-to carabiner for most climbing racks. 

They are designed to hold loads off-center toward the stronger, non-gated side. One of the great things about this shape is the lighter weight doesn’t compromise the overall strength of the carabiner. 

You’ll also notice that this carabiner shape is usually used to connect gear to your harness or in quickdraws.


  • It provides a very strong shape
  • Larger gate openings than oval-shape
  • Easy to use


  • Often more expensive than the oval-shape
  • Smaller gate opening than asymmetric D-shape carabiners

Asymmetric D-Shaped Carabiners

Asymmetric D-shaped carabiners (offset D-carabiners) are among the most popular designs out there.

They work the same way as the regular D-shape but have a far larger gate and can be lighter because of the smaller end.

Most climbing racks will have their fair share of asymmetric D-shaped carabiners, making it a must for anyone looking to build up their rack.


  • Large gate opening 
  • Locking variations 
  • Very strong and lightweight 


  • It can be more expensive

HMS Carabiners

HMS carabiners or also known as Pear-shaped are often used for belaying, rappelling, and setting up anchor points.

You’ll notice there isn’t much difference between the asymmetric D-shape and the HMS carabiner. You will see that the HMS carabiner is designed with a broader and more symmetrical top.

This feature makes setting up hitches much more manageable than other carabiners on the market. 


  • Explicitly designed for belaying and rappelling
  • Large Gate Opening
  • More symmetrical top


  • Usually more expensive

Oval Carabiners

Their design provides versatility in attaching gear, as they offer two distinct gate orientations, making them ideal for situations where equipment needs to be loaded efficiently. 

Oval carabiners are often used in aid climbing, big wall climbing, and rescue operations. They provide stability for gear like pulleys and ascenders, requiring consistent orientation.

The problem is:

Oval carabiners tend to be less strong along their minor axis than other shapes, so they are chosen for their versatility rather than maximum strength, making them a valuable addition to a climber’s rack.


  • Limits load shifting
  • They can hold more gear


  • Small gate opening
  • Not known for their strength

The Carabiners Weight

The weight of your carabiner is a critical consideration in various outdoor activities, especially in climbing and mountaineering, for several reasons:

  • Reduced Overall Gear Weight: Climbing and mountaineering often involve carrying a substantial amount of gear, including ropes, protection, harnesses, helmets, and more. When hauling this gear up a route or mountain, every ounce matters. Lighter carabiners reduce the overall weight of your equipment, making it more manageable, less fatiguing, and easier to transport over long distances.
  • Energy Conservation: Carrying lighter gear means expending less energy during a climb or hike. This can lead to improved endurance, reduced fatigue, and reduced risk of overexertion, which is especially important in challenging and extended alpine endeavors.
  • Efficiency in Movement: Lighter carabiners can significantly improve your climbing efficiency. When you’re reaching for a carabiner to clip or unclip your rope, a lighter one is easier to manipulate quickly. This is particularly crucial in situations where speed and precision matter, such as sport climbing or alpine routes with complex sequences.
  • Less Stress on Anchors: When building anchor systems or setting up belay stations, the cumulative weight of carabiners can stress the anchor points. Lighter carabiners reduce this stress, potentially increasing the safety and longevity of your anchor systems.
  • Multi-Pitch Climbing: Every ounce you carry becomes more noticeable during multi-pitch climbing, where you ascend multiple rope lengths and spend extended periods on the wall. Lighter carabiners help make multi-pitch climbs more comfortable, as you’re less burdened by the weight of your gear.
  • Fast and Light Climbing: Minimizing gear weight is a fundamental principle in fast and light climbing styles, such as speed climbing or alpine-style ascents. Lighter carabiners contribute to the overall strategy of moving quickly with a minimal and lightweight rack.

However, balancing weight and other factors like strength, durability, and functionality is essential. Ultralight carabiners may sacrifice some of these attributes, so it’s something to be aware of.

Your Carabiners Size

The size of your carabiner is an essential consideration in outdoor activities, particularly in climbing and mountaineering, for the following reasons:

  • Compatibility with Gear: The carabiner size must match the gear you intend to use. For example, carabiners that attach a climbing rope to protection (such as nuts, cams, or quickdraws) should have an appropriate gate opening size to accommodate the gear’s thickness. An improperly sized carabiner may not clip securely or could cause rope drag.
  • Ease of Use: The carabiner’s size affects how easy it is to clip and unclip. Smaller carabiners may be more challenging to manipulate, especially when wearing gloves or in stressful situations. Larger carabiners offer more space for your fingers, making them easier to handle.
  • Strength: Smaller carabiners generally have lower strength ratings than larger ones made from the same material. This is because smaller carabiners have less material to distribute the load, so they may not be suitable for high-load situations. Larger carabiners are often used in anchor systems or for connecting multiple pieces of gear because they can handle greater forces.
  • Weight: The size of the carabiner contributes to its overall weight. Smaller carabiners are lighter, benefiting weight-conscious climbers looking to reduce their gear’s overall load. However, balancing size, weight, and strength is essential, as overly small carabiners may compromise safety.
  • Gate Clearance: The gate clearance, or the space inside the carabiner where the rope or other gear is clipped, can vary in size. Larger carabiners generally have larger gate clearances, making it easier to clip and unclip ropes or other equipment.
  • Specific Applications: Different climbing and mountaineering situations may require different carabiner sizes. For example, compact and lightweight carabiners are often preferred for alpine climbing and mountaineering, while larger carabiners are commonly used in traditional or sports climbing scenarios.

The size of your carabiner is a crucial consideration that impacts compatibility, ease of use, strength, weight, and suitability for specific climbing scenarios. 

Choosing the right carabiner size for your intended purpose is essential to ensure safety and performance while enjoying outdoor activities.

Understanding The Strength Ratings

Carabiner strength ratings are an essential aspect of climbing safety, and they work based on specific testing and standards established by relevant organizations and manufacturers. Here’s how carabiner strength ratings work:

  1. Testing Standards: Carabiners are subject to standardized testing procedures established by organizations like the International Climbing and Mountaineering Federation (UIAA) and the European Committee for Standardization (CEN). These standards outline the procedures and criteria for testing carabiners to ensure their safety and performance.
  2. Strength Properties: Carabiners are rated for their strength in three primary directions:
    • Major Axis: This is the strongest direction of the carabiner and is the axis along which it is designed to bear most of the load. Climbing carabiners typically have their major axis strength labeled.
    • Minor Axis: This is the direction across the gate, perpendicular to the major axis. Carabiners are significantly weaker in this direction.
    • Gate Open: The carabiner’s strength with the gate open is generally the weakest. While carabiners are not intended to be loaded in this configuration, it’s essential to know their gate-open strength for safety considerations.
  3. Breaking Strength: Carabiner ratings are expressed in kilonewtons (kN), a unit of force. The breaking strength is the maximum force a carabiner can withstand before failing. Climbing carabiners typically have breaking strength ratings ranging from around 20 kN to 30 kN or more, depending on their design and intended use.
  4. Safety Factors: Carabiner strength ratings are determined with significant safety margins to withstand the stresses encountered during climbing and other outdoor activities. This means that carabiners are rated well above the typical forces experienced in climbing, providing a buffer for safety.

Final Thoughts & Takeaways

Understanding the differences between carabiners is not easy when you’re entering the world of climbing, but I’m hoping this article has shed some light.

The important thing to remember is that each carabiner has a particular job it’s good at, so make sure you use them for their intended function.

You should also keep an eye on their kN rating; the higher, the better, but anything ranging between 20kN and 30kN is perfect for climbing.

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