How to Choose the Right Compression Class
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Compression garments are measured in millimeters of mercury (mmHg), and they come in classes that describe how firm they are. The most common class for managing lymphedema is 20 to 30 mmHg, with 30 to 40 mmHg used for more significant swelling and 15 to 20 mmHg for lighter support. Your therapist or doctor recommends the right class for you, and getting the fit right matters just as much as the number.
Key takeaways
- mmHg measures how much pressure the garment applies. Higher numbers mean firmer compression.
- Common classes: 15 to 20 mmHg (lighter), 20 to 30 mmHg (most common for lymphedema), and 30 to 40 mmHg (firmer).
- Your therapist or physician should recommend your class based on your needs.
- Correct measurement and fit are essential. The right class in the wrong size will not work well.
What does mmHg mean?
mmHg is simply a unit of pressure. On a compression garment, it tells you how much gentle squeeze the fabric provides. Graduated compression is firmest at the far end of the limb and eases as it moves up, which helps guide fluid in the right direction.
The compression classes
- 15 to 20 mmHg: a lighter, everyday level of support.
- 20 to 30 mmHg (Class 1): the most commonly prescribed level for managing lymphedema.
- 30 to 40 mmHg (Class 2): a firmer level for more significant swelling.
Higher is not automatically better. The right level is the one matched to your condition by a professional.
Who decides your compression class?
Your lymphedema therapist or physician determines the appropriate class based on your diagnosis, the degree of swelling, and your overall health. If you are not sure what level you need, ask them directly rather than guessing, since too little or too much compression can both be unhelpful.
Why fit matters as much as the class
A garment in the correct class will only work if it fits your limb properly. Compression sizing is different from your clothing size, so it is worth measuring carefully with a tape measure and following a size guide, or having a fitter or therapist help. A garment that is too loose will not compress effectively, and one that is too tight can be uncomfortable or cause problems.
Getting the measurement right
Measure at the points your size guide indicates, ideally earlier in the day before swelling builds. Pay attention to both width and length, since sleeves and socks come in short and long options. When in doubt, reach out for fitting help.
Frequently asked questions
What compression level is best for lymphedema?
The most common level is 20 to 30 mmHg, but the right choice depends on your condition and should be recommended by your therapist or physician.
Is a higher compression class always better?
No. More compression is not automatically better and can even be counterproductive if it is more than you need. The goal is the correct level for you, professionally recommended.
How do I know my size?
Measure your limb with a tape measure following a size guide, since compression sizing differs from clothing sizes. A fitter or therapist can help you get it right.
Can I choose my own compression class?
It is best not to self-prescribe. Ask your therapist or physician, since the right class depends on your specific situation.
This article is for general education and is not medical advice. Your compression class should be determined by your physician or a certified lymphedema therapist. Trusted resources include the Lymphatic Education and Research Network (LE&RN) and the National Lymphedema Network.
Written by the LympheDIVAs team. We have made beautiful, medical-grade compression for people living with lymphedema since 2006.