What is a carabiners gate opening?

Gate opening refers to the distance between a carabiner’s nose and the gate, when the gate is fully open.

Carabiner Gate Opening - circle

The larger the gate opening the more rope/webbing/gear you can clip into it. It is also associated with easier clipping.

Although it’s tempting to assume that a large gate opening is better, gate opening alone does not guarantee a superior carabiner. A larger gate opening signifies the potential for the carabiner to be easier to clip and hold a lot of gear, but this could easily be thwarted by the angle of the nose, the width of the basket (bottom of the carabiner), or the usability of the gate (how easy it is to open and how your finger(s) fit).

How is gate opening measured:

To measure gate opening accurately, manufacturers use a metal pin of a precise millimeter diameter. This pin needs to be able to pass through the narrowest area of the gate opening.

For most carabiner shapes (Offset D, HMS/Pear, Oval), the minimum gate opening requirement by the governing bodies is 15mm.

In the test, a 15mm pin has to be able to pass through the gate opening and then the gate has to open without hitting the pin, as it nests in the top corner of the carabiner. This same test occurs with two 11mm pins – the gate must open without touching this twin/half rope simulation.

Measuring the openings using calipers / a ruler is a less accurate measurement than using a metal pin but it can give a reasonable estimate if you want to test your own equipment (or what’s available at the shop).

Range

15 mm – 33 mm is the typical range covering most climbing carabiners. Note: Even the smallest and lightest certified climbing carabiner, Edelrid’s Nineteen G, has a 18 mm gate opening.

Although the size and shape of a carabiner determines the gate opening, we were surprised to find the average gate opening of each shape differed by only 2.4mm and the difference in the mode (most common gate opening) between shapes to be only 2 mm.

Shape	Range	Mode (most common)	Median	Average
Oval	15 mm – 27 mm	22 mm	20 mm	20.1 mm
Pear / HMS	15 mm – 32 mm	24 mm	23 mm	22.5 mm
D	15 mm – 33 mm	22 mm	22 mm	22 mm
Offset D	15 mm – 33 mm	22 mm	22 mm	21.9 mm

*Numerical data was created from all the carabiners catalogued on WeighMyRack in 2015.

It makes sense that oval carabiners have the smallest gate opening as they were the first carabiner shape and future carabiner designs prioritized a larger gate opening in addition to lower weight and greater strength.

When we looked at sub-sets of carabiner styles, we found the biggest differences in gate openings when comparing bent gate to straight gate carabiners.

Shape	Mode (most common)	Median	Average
Bent, Offset D	25 mm	24 mm	23.7 mm
Straight, Offset D	17 mm	21 mm	21. 1 mm

This difference in gate openings makes a lot of sense because bent gate carabiners were specifically designed to have a larger gate opening. A bent gate carabiner goes on the rope end of a quickdraw and allows the rope to fit more easily into the carabiner.

Weight vs Gate Opening

There is no strong correlation between weight and gate opening although it is an interesting graph to look at. Some of the lightest carabiners have the largest gate openings. This is most likely because the reduced size of the light carabiners demands usability to be integrated in all areas including gate opening. A majority of the small light-weight carabiners are also hot-forged which allows the manufacturers to move metal around easier and create more optimal shapes.

The graph below contains the lightest 175 carabiners and you’ll notice many of the bent gates are represented by spikes on the chart.

We only graphed the lightest 175 carabiners due to Google Graphs limits for this chart type. If you super want to geek out, we made this same graph separating out the non-locking carabiners into these categories: wire gates, solid gates, straight gates, and bent gates.

What is the best gate opening?

Good question. It’s impossible to choose the best carabiner based on gate opening only. The answer will change depending on how you’ll use the carabiner. What matters most is how many items (and the size of items) you want to easily fit into the carabiner. The more items you want to fit into the carabiner, the larger the gate opening should be. (We give examples in the next section).

It’s not guaranteed that larger gate opening will snag less. This could be true, but the carabiner body design could thwart all the effort of the larger gate opening.

WeighMyRack.com/carabiner is the only website on the planet that allows you to see every carabiner and narrow the search by gate opening.

A slider for gate opening helps you compare carabiners on WeighMyRack.com/carabiner

Searching by gate opening can be most helpful if you have a currently frustrating carabiner where the gate opening feels too small (doesn’t hold enough, or is a pain to use with your sausage fingers). Knowing that frustrating gate opening size you can put that in as the lower limit. Otherwise, if you’re debating between a few very similar carabiners, choosing the carabiner with the largest gate opening could be a way to make a final decision.

General Guidelines of Gate Opening Size

top of your quickdraw a straight gate is the standard here, and 17 mm – 22 mm is great

bottom of your quickdraw pick a bent gate that has a 23 mm – 26 mm gate opening

There are many ways to clip carabiners to bolts and put the rope into the carabiner, and you may find a carabiner with a larger (or smaller) gate opening to be helpful.

wire gate vs straight gate — *An example of the now retired CAMP Orbit Wire bent gate for the rope side and CAMP Orbit Wire straight gate for the bolt side*

an anchor carabiner that needs to hold multiple pieces of gear/webbing: 19 mm+

edelrid-locker-gate-comparison — *It looks like the Edelrid Pure Slider, 18 mm gate opening (left) would barely hold anything and the and HMS Strike Slider, 21 mm gate opening (right) would hold a ton. But… (see the next photo)*

Locker basket size comparison — *It turns out, the Pure Slider can still hold a fair amount of gear and the gate will fully open, though definitely not as much nor as easily as the Edelrid HMS Strike Slider*

The combination of gate opening and basket size are the two most significant factors when determining how much gear you can effectively get into a carabiner.

The relationship between basket size and gate opening also impact the technique required to clip the carabiner. If the basket and gate opening are both small, it may not be possible to clip with a full finger(s) in the basket because your fingers will get in the way of the rope sliding into the carabiner.

Bottom Line

Gate opening is less important than how the carabiner feels in your hand and how you can operate the carabiner in a clipping situation. This is because the carabiner body shape, nose design, and shape of the basket can completely change the feel and usability. Given two carabiners that acted the same otherwise, we’d choose the carabiner with the larger gate.

That being said, you will want a larger gate opening if you want to use the carabiner to hold lots of webbing or rope, such as in an anchor situation. For anchors, a small gate opening can slow you down and become a source of intense frustration, and in this case, higher clearance would make for a much nicer experience.

Adding bias towards a larger gate opening is a fantastic option once you’ve narrowed down your choice to a few similar carabiners and need to tip the scale towards choosing the best carabiner for your needs.

To Find The Best Carabiner

We recommend trying out the carabiners your climbing partners and visiting as many gear shops and handling as many carabiners as possible. Often, you will know ‘the one’ after you test it, it’ll either fit in your hand really well, or somehow just make life easier.

Want to See All The Carabiners (over 1000)?

At WeighMyRack, we list every carabiner and give you filters for shape, gate type, gate opening, price, weight, brand, and features like visual warning, keylock, available in a rack pack, or if it has a belay keeper. You can also filter by on sale carabiners with discounts >20%.

See & Compare Every Carabiner

See Every On Sale Carabiner