Getting the right size is the single most important step to making sure your knee brace feels supportive and comfortable — not too tight, not too loose. Here's how to find your size in under a minute.
Why fit matters
A brace that's too loose slides down and won't give you the support you're looking for. One that's too tight can feel restrictive during the day. The right fit sits snugly without digging in — so you can wear it from morning to night and forget it's even there.
How to measure
Our brace is sized by your thigh circumference, just above the knee:
- Grab a soft measuring tape.
- Stand up with your leg relaxed.
- Measure around your thigh 4 inches (about 10 cm) above the top of your kneecap.
- Note the measurement and match it to the chart below.
Not near a tape measure? You can also use your body weight as a quick guide — see the Weight column below.
FIXEDFORM size chart
| Size | Thigh circumference | Weight |
|---|---|---|
| M | 15.7" – 18.9" / 40 – 48 cm | 135–155 lbs (61–70 kg) |
| L | 19.3" – 21.7" / 49 – 55 cm | 156–180 lbs (71–82 kg) |
| XL | 22.0" – 23.6" / 56 – 60 cm | 181–210 lbs (82–95 kg) |
| 2XL | 24.0" – 25.6" / 61 – 65 cm | 211–250 lbs (96–113 kg) |
| 3XL | 26.0" – 27.6" / 66 – 70 cm | 251–300 lbs (114–136 kg) |
| 4XL | 28.0" – 30.7" / 71 – 78 cm | 301–340 lbs (137–154 kg) |
| 5XL | 31.1" – 33.9" / 79 – 86 cm | 341–380 lbs (155–172 kg) |
A few quick tips
- Between two sizes? If you prefer a firmer, more supportive feel, go with the smaller size. If you prefer a relaxed fit, size up.
- Measure both legs if you're buying for both — they can differ slightly.
- If your thigh measurement and weight suggest different sizes, go by the thigh measurement — it's the more accurate guide.
Still not sure? You're covered.
Every FIXEDFORM brace is backed by our 60-Day Guarantee. If the size isn't right, just reach out to support@fixedform.us and we'll help you exchange it for the perfect fit.