Carabiners are important safety tools in climbing, rescue, and load-bearing work. Their strength can vary depending on their type, use, and loading method. Knowing the weight and force limits of a carabiner helps you use it safely and effectively. Many people confuse weight with force, but they are not the same. A carabiner that holds a heavy load might fail under the force of a fall. This article explains the strength ratings, how to interpret them, and what to consider when using carabiners in both daily and professional tasks.
What Does kN Mean in Carabiner Ratings?
Each carabiner comes with strength numbers marked in kiloNewtons (kN). The strength rating on a carabiner indicates the maximum force it can withstand before breaking. One kilonewton is equal to approximately 100 kilograms, or 225 pounds, of force. A typical climbing carabiner has a strength of 20–24 kN on the major axis. That means it can withstand a force of about 4,500 to 5,400 pounds when used correctly. This does not mean it can hold that weight without movement. A fall creates much more force than the weight of your body alone.
Understand the Load Directions
A carabiner’s strength depends on how it is loaded. There are three common load directions:
- Central axis (strongest): The long side of the carabiner with the gate closed.
- Minor axis (weaker): Sideways loading, which reduces strength to about 7 kN.
- Open gate (weakest): When the gate is open during use, it can withstand a load of up to 6 kN.
Always ensure the load remains on the major axis with the gate closed to stay within safe limits.
Choose the Right Carabiner for the Task
Different jobs need different kinds of carabiners. For rock climbing, use carabiners rated at least 20 kN. These are tested to handle the high forces caused by a fall. In rescue work or when hauling heavy gear, look for steel carabiners with ratings exceeding 25 kN. For holding gear or light loads, you can use smaller utility carabiners, but never trust them for safety-critical tasks. Always read the rating marks on the spine of the carabiner.
Tips to Keep Carabiner Use Safe
Follow these simple rules to reduce risk when using carabiners.
- Do not cross-load or load on the gate.
- Use locking carabiners when possible to prevent gate opening.
- Avoid dropping them, as damage might not be visible.
- Check for wear, cracks, or gate problems.
- Retire a carabiner if it shows signs of damage or becomes stuck.
Conclusion
Using carabiners without understanding their strength ratings can be dangerous.
You must always check the kiloNewton (kN) rating on each carabiner and match it with the task at hand. Whether climbing, rigging, or carrying loads, using the right carabiner the right way makes all the difference. Stick to known load directions, lock the gates when needed, and inspect your gear regularly. These habits reduce accidents and extend the life of your equipment. Choose wisely, follow the markings, and stay within the safe limits every time you use a carabiner.