To measure your thigh for a knee brace, sit with your knee bent to 90 degrees, find the top of your kneecap, and measure 14 cm (5.5 in) up the thigh from that point. Wrap a soft tape around the leg there, snug but not tight, and read it in centimetres. That one number is your knee brace size.
Below is the DialGuard knee brace size chart in centimetres and inches, the step-by-step method, and the part most knee brace sizing guides skip: the same hardware ships with three different size charts, one of them by body weight. If you are asking what size knee brace do I need, that is why the answer is a tape, not a guess.
Why knee brace sizing goes wrong so often
Size is the second most common complaint in this category after sliding down. On one Amazon US knee brace listing with 18,591 ratings, size has 198 customer mentions and 149 of them are negative, and Amazon's own summary notes that buyers say the small runs too big (amazon.com/dp/B0997VXC6D, checked 2026-08-30). An Australian buyer of this exact style of dial brace wrote that the unit was labelled L and they could not get it on. Too big and too small, on the same style of product: that is what happens when a chart is vague, built on body weight, or silent about where on the thigh to measure.
Size also feeds the other big complaint, because a sleeve a size too large has nothing to grip and creeps down the calf. On the highest-volume knee brace listing on Amazon US, 813 customers commented on whether it stays in place and 375 of those comments were negative (amazon.com/dp/B07F9W9BHX, 46,128 ratings, checked 2026-08-30). The other causes are in why your knee brace slides down and what actually holds it; a correct measurement is the first fix.
How to measure your thigh for a knee brace: step by step
You need a soft tape measure, the dressmaker's kind rather than a metal builder's tape, and about 20 seconds. No soft tape? Use string, then lay it against a ruler.
- Sit down. Foot flat on the floor, knee bent to 90 degrees, leg relaxed.
- Find the top of your kneecap. Press with your thumb to find the upper edge of the bone.
- Go 14 cm (5.5 in) up the thigh. Measure straight up from that edge and mark the spot with a pen or a finger.
- Wrap the tape around the whole thigh at the mark. Keep it level all the way round, parallel to the floor.
- Pull it snug, not tight. The tape sits flat on the skin without denting it. Measure on bare skin or thin tights, never over trousers.
- Read it in centimetres and write it down. Measure again. If the two readings differ by more than 1 cm, take a third and use the middle one.
- Measure the leg the brace is for. Legs are rarely identical, and DialGuard is side specific, so a Left and a Right can be different sizes.
DialGuard knee brace size chart in cm and inches
Measure 14 cm (5.5 in) above the top of the kneecap, then read across. This is the chart on the manufacturer's own retail listing for this hardware, and the one we build exchanges around.
| Size | Thigh circumference, 14 cm (5.5 in) above the kneecap | Inches |
|---|---|---|
| M | 36 to 42 cm | 14.2 to 16.5 in |
| L | 42 to 48 cm | 16.5 to 18.9 in |
| XL | 48 to 54 cm | 18.9 to 21.3 in |
| XXL | 54 to 62 cm | 21.3 to 24.4 in |
Four sizes cover 36 to 62 cm (14.2 to 24.4 in), and the top of that range matters: "knee brace for large thighs" is a real search, and an XXL to 62 cm is what makes a pull-on sleeve workable on a bigger leg. Each unit is side specific, so you choose Left or Right as well as a size. The adjustable knee brace product page carries the same chart.
On a boundary, size up
If your measurement lands on a line, 42, 48 or 54 cm, take the larger size, and do the same within 0.5 cm of it, since tape tension alone can move a reading that far. A brace you cannot pull over your calf is useless, and the knit does not stretch its way into a size. A brace one notch loose can be dialled in: the knob winds a lace cable that pulls the sleeve in around the whole circumference, a range a fixed sleeve or a pair of straps does not have. That difference is the subject of dial knee braces versus velcro straps. The tape only has to get you into the right band. The dial handles the rest.
Why the same knee brace comes with three different size charts
This explains a lot of the sizing reviews. The dial brace sold as DialGuard is made by one manufacturer and sold under more than one label, and when we checked the published size guides on 2026-08-30 we found three different charts for the same hardware.
| Where the chart appears | Medium thigh circumference | Sizing method |
|---|---|---|
| Manufacturer's own Amazon retail listing (the chart DialGuard uses) | 36 to 42 cm | Thigh circumference, 14 cm (5.5 in) above the kneecap |
| A competitor's size chart image | 35 to 40 cm | Thigh circumference |
| Manufacturer's own direct-to-consumer store | 36 to 48 cm | Thigh circumference, with a parallel body-weight scale (M is 40 to 60 kg) |
A 41 cm thigh is a Medium on two charts and a Large on the third. A 45 cm thigh is a Large on the chart we use and a Medium on the manufacturer's own store. And two people who both weigh 55 kg can have thighs several centimetres apart, because body weight says nothing reliable about one leg 14 cm above the knee. At least one of these charts has to be wrong, and a buyer who reads the wrong one orders the wrong size.
We use the manufacturer's retail-listing chart because it is the one printed beside the product people actually receive, and we do not publish a weight scale. If the chart lets you down anyway, the 30-Day Fit Promise covers it: the wrong size is swapped free, or refunded.
Snug, not tight: what a correct fit feels like
Size gets the sleeve onto the right part of the leg; the dial sets the tension once it is there. Trying to fix a sizing problem with tension is how a brace ends up cutting in or sliding.
A correct fit, before you touch the knob, has the sleeve flat on the leg, the silicone gel ring around the kneecap rather than over it, and the anti-slip dots on the inner face touching skin. It should slide on over the calf with the leg straight. Then bend the knee to about 30 degrees, turn the knob click by click until the sleeve feels firm and even, walk five steps, and add a click if it feels loose. Tighter is not better.
Pooled across three trials of knee braces with 234 participants, the effect on pain scores did not reach statistical significance (mean difference -0.46, 95% CI -1.16 to 0.24, p = 0.19), and in one of the included trials skin discomfort or abrasion was reported in 16 of 44 braced knees, which is 36% (Smith 2015, Cochrane Database Syst Rev 2015(12):CD010513, PMID 26645724). Study of knee braces generally, not this product. A well-fitted brace is a comfort and stability support, not a fix for anything; if you have an injury, see a professional. The skin finding is the practical one: wear it for the session, then take it off and let the skin breathe. If you are also buying an ankle brace, measure for it separately; a knee size tells you nothing about an ankle.
Re-measure after two weeks of training
Thigh circumference is not fixed. Fourteen days of graded leg work, the plan in The Load Ladder guide that comes with every DialGuard order, can change the reading for some people. Two signs say re-measure: the dial is at either end of its travel (fully wound and still loose, or barely wound and already firm), or the sleeve has started to migrate.
Re-measure the same way every time: seated, knee at 90 degrees, 14 cm (5.5 in) above the kneecap, soft tape, snug not tight, bare skin, centimetres. Crossed a boundary? The 30-Day Fit Promise covers a free size swap, and day 14 is well inside that window. Still in the same band? Two or three clicks on the knob is the whole adjustment.
Frequently asked questions
What size knee brace do I need if my thigh measures exactly 42 cm?
Size up to Large. The DialGuard chart runs Medium 36 to 42 cm and Large 42 to 48 cm, and a reading on the line goes to the larger size. A sleeve you cannot pull over your calf cannot be fixed, while one that is slightly loose can be dialled in with the knob. The same rule applies at 48 and 54 cm.
Should I measure my thigh sitting or standing?
Sitting, with your foot flat on the floor and the knee bent to 90 degrees. Standing with the leg straight changes the shape of the thigh muscles and can shift the reading, and it makes the 14 cm (5.5 in) mark above the kneecap harder to find. Use the same position every time you re-measure so the numbers compare.
Can I measure in inches instead of centimetres?
Yes. Measure 5.5 in above the top of the kneecap and read the inches column: M 14.2 to 16.5 in, L 16.5 to 18.9 in, XL 18.9 to 21.3 in, XXL 21.3 to 24.4 in. Centimetres are finer, so if your tape shows both, read the centimetre side. One inch is 2.54 cm.
Do I need a different size for each knee?
Possibly. Legs are rarely identical, so measure each thigh separately and order the size each reading gives you. DialGuard is side specific, so a pair is ordered as one Left and one Right, and the two can be different sizes. Do not assume the second leg matches the first; the second measurement takes 20 seconds.
What happens if the size is wrong when it arrives?
Do not force it. A brace you cannot get past the calf, or one that slides after the knob is set, is the wrong size, not a tight fit. Email us within 30 days and the 30-Day Fit Promise applies: the wrong size is swapped free, or refunded if you prefer. Measure again before you reply so we send the right size.