Three measurements determine a proper crutch fit: your standing height, the gap under your armpit, and the bend in your elbow. Get the type right first, because the measuring rules change the moment you switch between underarm and forearm crutches. Most sizing mistakes show up within the first ten steps you take, not on the measuring tape.
Below is a practical walkthrough that covers picking the right crutch type, taking baseline measurements, setting length and handgrip, running a 60-second self-test, and spotting trouble signs before they turn into a fall or nerve pain. It is written for adults recovering from a foot or ankle injury, caregivers sizing for a child, and anyone switching from sneakers to a post-op boot.
Start by Identifying the Right Crutch Type for Your Situation
The two main types you will meet at a pharmacy or physical therapy clinic are axillary (underarm) crutches and forearm (Lofstrand) crutches. Axillary crutches are the default pick for short-term recovery after a broken ankle, a foot sprain, or a post-op boot phase, and they are sized by overall length plus handgrip height. Forearm crutches, sometimes called elbow crutches, wrap a cuff around your forearm and are typical for longer-term mobility support, cerebral palsy, or permanent lower-leg weakness; they require sizing of both the handgrip and the cuff that encircles the arm.
Why the Type Decision Locks in Every Measurement After It
Picking the wrong category quietly ruins everything that follows. A forearm crutch sized the way you would size an underarm crutch will sit too low at the cuff and leave your wrist cocked back. An axillary crutch sized like a forearm crutch will leave a wide, dangerous gap under the armpit because the cuff is missing entirely. Confirm the type your care team recommended, or match it to the injury: most foot and ankle recoveries start with axillary, while lifelong mobility needs usually point to forearm.
| Feature | Axillary (Underarm) Crutches | Forearm (Lofstrand) Crutches |
|---|---|---|
| Best for | Short-term leg or foot injury recovery | Long-term or permanent mobility support |
| What you size | Overall length and handgrip height | Handgrip height and forearm cuff length |
| Resting point | Padded axillary pad under the armpit | Cuff encircling the upper forearm |
| Common brands | Drive Medical, Medline, Invacare | Carex, Lofstrand, Ergobaum |
| Typical user | Post-op patients, sprains, fractures | People with chronic mobility needs |
Tip: If you’re switching between the two types mid-recovery, measure from scratch. The numbers don’t transfer.
Take Two Baseline Measurements Before Touching the Crutches
You need a tape measure, a flat floor, and the shoes you’ll actually wear during recovery. Most sizing errors start before the crutches come out of the box, when someone measures barefoot and then walks around in a post-op boot with a 1.5-inch sole. The sole height shifts every number that follows, so put the recovery shoes on first and leave them on for every measurement.
Record Standing Height in the Recovery Shoes
Stand tall against a wall or doorframe with your shoes on, mark the top of your head, and measure from floor to mark in inches. Write it down. That figure becomes your reference for the quick axillary-length formula and the weight-bearing capacity check. Standard adult crutches support 250 to 300 pounds, bariatric models are required for heavier users, and most boxes print a height range that tells you in seconds whether your height falls inside their adjustment window.
Measure Wrist Crease to Floor With the Arm Relaxed
Hold your arm straight down at your side, palm facing forward, fingers gently curled. Measure from the crease where your hand meets your forearm straight down to the floor. This wrist-crease-to-floor figure is more reliable than height-based estimates for setting the handgrip on either type of crutch. It matches the way your arm actually hangs while walking, not the way it looks when you stand at attention.
- Standing height: Wall-to-crown measurement in recovery shoes.
- Wrist crease to floor: Arm relaxed, palm forward, tape measure straight down.
- Body weight: Confirm it’s under the crutch’s printed capacity, or pick a bariatric model.
- Recovery shoe sole height: Sneaker, post-op boot, or dress shoe changes everything.
Tip: For axillary crutches, subtract roughly 16 inches from your standing height as a starting length, then refine it with the wrist-crease method on the handgrip.
Set the Overall Length So a 2–3 Finger Gap Sits Under the Armpit
For axillary crutches, the top pad sits about 1.5 inches below your armpit, which is roughly a two- to three-finger gap. The pad should cradle your ribcage with the shoulder relaxed, not lift the shoulder or press into soft tissue. Standing with shoulders down and back is the easiest way to feel whether the pad is doing its job or just leaning on you.
Lock Every Adjustment and Repeat on the Second Crutch
Push the spring buttons or pop the push-pins all the way through the adjustment holes so the inner tube sits flush. A gentle shake test catches any half-locked position before you put weight on it. Repeat every step on the second crutch. Legs and arms are rarely identical, and mismatched pairs are a common cause of an uneven gait that throws off your hips and lower back within a few minutes of walking.
Once the right crutch is identified, getting the length dialed in prevents the uneven gait that throws off hips and lower back.
Warning: Never let the axillary pad press into your armpit. Constant pressure there can compress the axillary nerve and cause tingling, numbness, or shoulder pain.
Position the Handgrip for a 15–30 Degree Elbow Bend
Plant the crutch tip on the floor and rest the pad under your arm, then slide the handgrip up or down until your elbow settles into a 15 to 30 degree bend. That range keeps your triceps loaded for the push-off and prevents the locked-arm posture that wastes shoulder energy on every step. A bent wrist with the palm flat on the handle is an early warning sign the handgrip is set too high.
Set the Cuff Correctly on Forearm Crutches
On forearm models, adjust the cuff opening so it encircles the forearm loosely without sliding off when you lift your hand off the grip. Most cuffs sit one to two inches above the elbow. Tighten every handgrip and cuff screw or push-pin fully, then tug the handle to confirm it will not slip under your body weight. Forearm sizing depends as much on the cuff as the grip, so skipping the cuff is a frequent mistake in quick-fit guides.
- Elbow bend: 15–30° with the crutch tip on the floor.
- Wrist position: Straight, palm flat, no cocking back.
- Forearm cuff: One to two inches above the elbow, loose but secure.
- Lock check: Push-pins flush, no clicking under weight.
Run a 60-Second Standing and Walking Self-Test Before Relying on Them
Stand upright with shoulders down and back, not hunched over the pads. The crutches should feel like an extension of your arms, not something you are leaning forward onto. Walk a short distance on level ground using the three-point gait your physical therapist recommended, and listen for scraping, clicking, or the crutches sliding out of position. Anything that scrapes or shifts mid-stride means a fitting problem hiding inside the measurements.
Recalculate Fit Any Time the Shoe Changes
Switching from a sneaker to a post-op boot, or from a flat to a heeled shoe, will throw off the armpit gap, the elbow angle, and the overall length. The wrist-crease-to-floor method absorbs small sole changes better than the height-subtraction formula, which is another reason the wrist number is worth keeping on a sticky note next to the crutches. Re-check fit for children and petite adults every few weeks as they grow, and confirm that the crutch’s maximum extension is long enough for tall users before purchase.
What a Good Walking Test Feels Like
A proper fit feels stable, with your weight going through your hands and not your armpits. You should be able to swing the crutches forward without your shoulders hiking up, plant the tips slightly ahead of your feet, and step through with the injured leg using partial or non-weight bearing as prescribed. If your shoulders burn after one minute or your good leg feels unstable, the fit is off and you should stop and adjust before continuing.
Recognize What Wrong Fit Feels Like and Keep the Tips in Working Shape
Crutches that sit too tall cause armpit soreness, tingling in the fingers, and shoulder pain from constant leaning. Lower the overall length the moment any of those sensations appear, because the axillary nerve runs right under the pad and prolonged compression can take weeks to settle. Crutches that are too short force you to hunch, push your wrist past a comfortable range, and leave you wobbly because you are essentially reaching down for the handles. Raise the length, then re-set the handgrip so the elbow bend stays in the 15–30° window.
Maintain the Rubber Tips and Re-fit During Recovery
Inspect the rubber tips regularly and replace them at the first sign of cracking, flattening, or loss of tread. Worn ferrules silently break an otherwise perfect fit because the crutch slides a fraction of an inch with every step. Most drugstores stock replacement tips by size; bring the old one to match the inner diameter. Schedule a quick re-fit every week or two during recovery, because swelling, weight change, or weaning off the crutches can quietly shift the ideal dimensions.
Warning: Tingling fingers, numb palms, or a constant dull ache in the shoulder are not normal side effects of using crutches. They are fit problems.
- Too tall: Axillary soreness, finger tingling, shoulder strain.
- Too short: Hunching, wrist pain, unstable stance.
- Worn tips: Slipping on smooth floors, even with perfect measurements.
- Weight change: Pressure points shift, handgrip may need to move.
The Bottom Line
Correct crutch fit is a hands-on process built on three checks: a two-finger gap under the armpit, a 15–30° elbow bend, and a quiet, stable 60-second walking test. Re-measure whenever the shoes change, replace the rubber tips when they wear, and treat any nerve tingling or shoulder ache as a sizing problem rather than something to push through. Large reviews in physiotherapy literature back up the same three-step approach used here, which keeps the rules consistent across short-term and lifelong users.
FAQ
How do you know if crutches are the right size?
Stand tall in your recovery shoes with the crutch tips on the floor. A proper fit leaves a two- to three-finger gap under the armpit and a 15–30° bend at the elbow when your hand grips the handle. Walk a few steps and confirm your shoulders stay relaxed and no tingling shows up in your fingers.
What happens if crutches are too short or too long?
Crutches set too long press into the armpit and can damage the axillary nerve, leading to tingling, numbness, or shoulder pain. Crutches set too short force you to hunch forward and overload your wrists, producing hand numbness and an unstable, wobbly gait.
How much space should be between the crutch and armpit?
Leave about 1.5 inches, or roughly two to three finger widths, between the axillary pad and your armpit. The pad should cradle the ribcage without lifting the shoulder, and your weight should travel through your hands rather than through the pad.
Where should the handgrip be when using crutches?
Set the handgrip so your elbow rests in a 15–30° bend with the crutch tip planted on the floor. The wrist should sit straight, palm flat against the handle, and never cocked back. On forearm crutches, the cuff should sit about one to two inches above the elbow.
How do you size forearm vs underarm crutches?
Underarm (axillary) crutches are sized by overall length from the armpit to the floor, plus handgrip height. Forearm (Lofstrand) crutches are sized by handgrip height and the cuff that wraps around the forearm, with the cuff typically sitting one to two inches above the elbow. The wrist-crease-to-floor method works for both handgrips.
Can crutches be adjusted after purchase?
Yes, most adult crutches have push-button or spring-clip adjustments on the lower leg and the handgrip, and forearm models also adjust the cuff. Always lock every pin fully, shake-test before walking, and re-check the fit if you change shoes, gain or lose weight, or shift from non-weight bearing to partial weight bearing.
