Menstrual cup sizing guide

asan’s sizing guide is simple: just choose based on your flow

Menstrual cup sizing can seem complicated and confusing. At Asan, we’ve simplified our menstrual cup size guide so that you choose your size based on one single factor: your period flow.

Below are some simple Q&As that should tell you all you need to know about sizing.

how to select menstrual cup size?

Select menstrual cup size based on your flow on the heavier days of your period. For most people, this is the second or third day. If you can wear a pad or tampon for 6 hours without soaking through, then our light/medium flow cup is the right size for you. If you tend to leak through tampons/pads more often, such as every 2-6 hours, then our heavy flow cup is better suited to your needs.

If you have heavy flow for the first few days followed by lighter flow, you can use the heavy flow cup throughout your period. That said, if you’d like to have a second cup as back-up, you can always purchase one of each size and use them at different stages of your period.

what are the differences between the light/medium cup and the heavy flow cup?

There are two differences: size and firmness. The heavy flow cup is slightly taller and wider than the light/medium flow cup, so that it can hold more menstrual fluid. The heavy flow cup is also made from slightly firmer silicone than the light flow cup. We designed it this way so that the heavy flow cup does not shift position and cause leaks — even for those users who experience very heavy periods.

i have light/medium flow. should i buy the heavy flow cup anyway as it holds more?

No, we advise choosing your size strictly based on your flow. The light/medium flow cup holds 25ml which is more than adequate for users with moderate flow. The heavy flow cup is designed specifically for those users who tend to run through several pads or tampons in a day.

does giving birth impact which size I should choose?

Giving birth does not impact which size you should use. The vagina is a highly elastic passage which can expand to let things in (or out!), but can also snap back into shape. We know of younger people who comfortably use our heavy flow cup, as well as mothers who have had multiple vaginal births who use our light/medium flow size.

what is the best size for teenagers?

For teenagers who are just starting out with menstrual cups, we suggest beginning with our light/medium flow cup. This is because it has a slightly smaller diameter and therefore has a smaller insertion point. Teenagers may also need to practice a few different folds, as they may prefer the punch-down fold to the c-fold (see our handy guide to folds for more details). Once you are comfortable with insertion and removal, you can switch to the heavy flow up (if needed).

what about the position of my cervix?

The cervix is the neck of the uterus, and is located at the very top of your vaginal passage. Some menstrual cup brands advise selecting size based on the position of your cervix. As there is very little difference in height between Asan’s light/medium flow cup and our heavy flow cup, the position of your cervix should not matter when selecting your size. If you would like to learn more about cervix height and menstrual cups, read this blog post where we explain it in detail.

i have a sensitive pelvic region. can i use either size?

If you have experienced sensitivity in the pelvic region in the past (for example, if you have previously used a menstrual cup and found that it was uncomfortable or pressed against your bladder), then we advise our light/medium flow size. This is because it is slightly less firm than our heavy flow cup.


help! i think i ordered the wrong size.

We understand that everyone’s body is different, and that you may not be fully satisfied with the size you choose. Please contact us explaining the issue you are facing. We will do everything we can to help. Where appropriate, we may offer you a replacement cup in a different size.


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