Properly sized crutches should leave a gap of two to three finger widths between the top of the crutch and your armpit, with the handgrip positioned at wrist height so your elbow bends about 25 to 30 degrees. Getting this right matters more than most people realize. Crutches that are too tall press into your armpit and can damage nerves and blood vessels, while crutches that are too short force you to hunch forward and strain your back.
Before You Start: How to Stand for Measuring
Put on the shoes you’ll actually be wearing while using the crutches. Stand upright, look straight ahead, and let your shoulders relax. You want your normal posture, not a stiff or exaggerated one. If you can’t bear weight on one leg, have someone support you or lean against a wall while a second person adjusts the crutches.
Place the tip of each crutch about 2 inches to the side of your shoe and roughly 6 inches in front of your toes. This is your starting position for all the adjustments that follow.
Sizing Axillary (Underarm) Crutches
Axillary crutches are the traditional type with a padded bar that tucks under your arm. Two things need to be set correctly: the overall height and the handgrip position.
Setting the Overall Height
With the crutch tips on the floor in the position described above, adjust the total length until the top pad sits two to three finger widths below your armpit. That gap is non-negotiable. The pad should never press up into your armpit, not even when you’re mid-stride and your body weight shifts. If you can comfortably slide two or three flat fingers between the pad and your armpit, you’re in the right range.
Setting the Handgrip
Let your arm hang straight down at your side. The handgrip should line up with the crease of your wrist. When you actually grip the handle, your elbow will naturally bend about 25 to 30 degrees. That slight bend is the sweet spot: it lets you push down through your palms efficiently without overloading your elbow joint. Research on crutch biomechanics found that raising the handgrip just one to two inches above the ideal position (increasing elbow bend past 30 degrees) doubled the force required at the elbow. Small errors create real strain over hundreds of steps a day.
Sizing Forearm (Elbow) Crutches
Forearm crutches have a cuff that wraps around your forearm instead of an underarm pad. They’re common for longer-term use and offer more freedom of movement. The handgrip rule is the same: position it at your wrist crease so your elbow bends roughly 30 degrees when gripping.
The forearm cuff should sit about one to two inches below the point of your elbow. If it’s too high, it restricts your elbow from straightening. If it’s too low, it won’t stabilize your arm properly. Most forearm crutches let you adjust both the cuff height and the handgrip independently, so set the handgrip first, then fine-tune the cuff.
Choosing the Right Size Range
Crutches come in youth, adult, and tall adult sizes. Each size has an adjustable range, so you need to start with the right category to land in the middle of that range rather than maxing it out at either end. As a rough guide, adult crutches fit people between about 5’2″ and 5’10”, while tall adult models cover 5’10” and above. Youth sizes work for children and shorter teens.
Weight capacity matters too. Standard crutches typically support 250 to 300 pounds. If you’re above that range, bariatric models rated up to 500 pounds are available and use reinforced tubing and wider pads.
Why Poor Sizing Causes Real Problems
A review of crutch-related injuries published in the medical literature identified improper fitting as a contributing factor in 22 documented cases of significant injury. The most common problem with underarm crutches was damage to arteries and nerves in the armpit, caused by the pad pressing directly into that space. Thirty-four cases involved arterial complications from axillary bar pressure alone. Forearm crutches carried a different risk: the cuff compressing nerves in the forearm, leading to numbness or weakness in the hand.
These aren’t just theoretical concerns. Many people instinctively lean on the armpit pad to rest, especially when tired. That habit, combined with crutches that are even slightly too tall, concentrates your body weight on a bundle of nerves and blood vessels that sit close to the surface. The result can be tingling, numbness, or weakness in the hand and arm that sometimes takes weeks to resolve.
How to Walk Safely Once They’re Sized
Your weight should always go through your palms on the handgrips, never through the armpit pads. The pads are there for light guidance and stability, not load-bearing support. Think of them as bumpers, not seats.
When standing still, use the tripod stance: keep your good foot flat on the ground and place both crutch tips slightly in front of your body at about a 45-degree angle from your foot. This triangle of contact points gives you the widest, most stable base.
To walk with one injured leg (the three-point gait), move both crutches forward together, then swing your good leg through to meet them. Your injured leg stays off the ground or touches down lightly, depending on what your provider has instructed. Keep your steps moderate. Overreaching with the crutches forces you to lean too far forward and makes falls more likely.
Quick Checks After Your First Day
After using your crutches for a few hours, pay attention to what your body is telling you. Redness or soreness in your armpits means the crutches are too tall or you’re resting weight on the pads. Pain in your wrists or hands suggests the handgrip is too low, forcing your wrists into an awkward angle. Shoulder and upper back fatigue is normal for the first few days as those muscles adapt, but sharp pain is not.
Recheck the two-to-three-finger gap and the wrist-crease alignment after your first day. Crutch bolts can slip, and your posture while actually walking often differs from how you stood during the initial fitting. A quick readjustment takes 30 seconds and can save you weeks of unnecessary soreness.