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Menstrual cups come in a whole host of sizes because every person’s body is different.

So, how do you know which one to pick? Well, it can take some experimentation. Here’s the lowdown on what to consider when choosing a menstrual cup size.

Small and large are the two most common sizes. But you may see small referred to as 1 or A and large called 2 or B.

Some brands have a bigger range of sizes, including ones to suit teens and people with a low cervix.

Rather confusingly, the size usually doesn’t relate to how much liquid the cup can hold but how wide it is.

No. There’s no standard sizing guide for menstrual cups, with one comparison finding small size diameters ranging from 39 mm to almost 49 mm across brands.

The small size is typically designed for people under the age of 30 who have no childbirth or pregnancy history.

The larger size is usually for people over the age of 30 or who have a history of pregnancy or giving birth.

A few manufacturers determine cup size by the heaviness of your menstrual flow.

Still, you may have to try a few to find the perfect fit.

Most brands have a comprehensive size guide, including recommendations based on your individual lifestyle.

Popular brands include:

  • Lunette offers model 1 for light to moderate flow and model 2 for moderate to heavy flow.
  • DivaCup offers model 0 for people 18 or under who are new to having a period, model 1 for people between 19 and 30 with a medium flow, and model 2 for people who are over the age of 30 or have a heavier flow.
  • MeLuna offers standard height and shorter cups for low cervixes in four different sizes ranging from teen designs to ones for people who’ve had multiple vaginal births.
  • Lena offers a small size for beginners and people with a low cervix, a large size for experienced users or people with a heavy flow, and an even smaller, softer design for people with sensitive anatomies.
  • Cora offers size 1 for people new to cups or who have a light to medium flow and size 2 for people who’ve given birth or have a medium to heavy flow.
  • Intimina offers a few innovative cups, including one for beginners and one that can be rolled as thin as a tampon to offer comfort for people who have a higher cervix or heavier flow.

While some factors are more important than others, considering all of the below when picking a size is worthwhile.

Age

Some brands prefer not to base cup sizes on age, but you’ll see it mentioned on many sites as it can affect the tightness of pelvic floor muscles.

Usually, smaller sizes are for people 30 and under and larger sizes are for those over 30.

You may also find smaller cups specially designed for teens new to having periods.

Birth history

Whether you’ve given birth or had a full-term pregnancy can also impact menstrual cup size.

Again, this is all about pelvic floor muscles and how pregnancy can weaken them.

So, smaller cups are usually recommended for people who haven’t delivered a child or had a full-term pregnancy and larger ones should feel more secure for those who have given birth or carried a pregnancy to full term.

Cervix height

Your cervix height is basically the length of your vaginal canal. It can change throughout your menstrual cycle so you’ll want to know its lowest position.

A higher cervix means a cup will sit further up. Small cups, which tend to be shorter, can therefore be problematic as you may struggle to reach them.

To figure out whether your cervix is high or low, insert your longest finger into your vagina on or just before the first day of your period and feel for your cervix.

It will be at the top of your vaginal canal and should feel similar to the tip of your nose —a smooth raised part with a dimple in the middle.

If your finger has to go all the way in before you reach your cervix, you likely have a high cervix. But if you reach it at the first knuckle, it’s likely low. In between is average.

Overall fitness

Age and pregnancy can relax pelvic floor muscles, but exercise can provide a tightening effect.

So if you’re fairly active, you may not need the larger size designed for older adults or those who’ve had a full-term pregnancy or given birth vaginally.

Similarly, trying out different kinds of firmness is worthwhile as you may find a stiffer cup is better for active days.

Menstrual flow

While not all menstrual cup manufacturers mention flow in sizing guides, it is something to think about.

A lighter flow —where you’d typically need to change a regular tampon or pad a couple of times a day —usually equates to a smaller menstrual cup.

A heavier flowwhere you’d need to change a highly absorbent tampon or pad every 2 to 3 hours —is often more suited to larger cup sizes.

Cup length

If a cup is too long to fit inside your vaginal canal, it probably won’t work and will likely be uncomfortable.

You can figure out the right length for you by measuring where your cervix is using the aforementioned method.

Cup diameter

Menstrual cup sizes usually refer to the cup’s diameter. So a small cup will have a smaller diameter than a large cup. (Remember that brand diameter sizes vary.)

The diameter size you choose will depend on other factors, such as your age and pregnancy history.

Cup capacity

Menstrual cups can hold different amounts of fluid.

Smaller ones tend to be able to hold 25 to 27 milliliters while larger ones have a volume of around 30 milliliters.

The capacity usually isn’t an important factor unless you have a heavy flow.

Do certain factors matter more than others?

Ensuring your menstrual cup is wide enough to securely fit inside your body is most important.

That means focusing on things like your age and birth history, rather than your menstrual flow.

Once you’ve had a bit of practice, you should be able to insert and remove your cup without much trouble. And once it’s in, it should feel comfortable.

If your cup is too small, you may notice leaks and may find it difficult to reach for removal.

But if it’s too big, it’ll likely cause discomfort as you may not be able to insert it as far in as it needs to go.

Are menstrual cups uncomfortable?

A menstrual cup should feel similar to a tampon —you know it’s there but it’s not uncomfortable.

The only time you’ll likely experience discomfort is if the cup’s too big for your body, too firm, or you’re attempting to remove it without first breaking the seal by pinching the base.

But if you’re feeling pain or discomfort when using the right size menstrual cup, consult with a healthcare professional. There may be an underlying condition causing pain, such as vaginismus.

Can you use a menstrual cup if you have severe cramps?

Menstrual cramps originate in the uterus, which isn’t where the menstrual cup sits. That means it’s unlikely they cause cramps.

Already having severe cramps shouldn’t be a barrier either —people with painful periods and conditions like endometriosis and PCOS do use menstrual cups.

Some people have found cups to help their cramps, while others have found they make them worse.

There’s currently no evidence to back either of these anecdotal findings up.

Will wearing a menstrual cup affect how you use the bathroom?

You can go to the bathroom normally with a menstrual cup.

It sits in the vaginal canal so won’t block any urination or bowel movement.

However, any pressure may push the menstrual cup down the vaginal canal. So it’s a good idea to ensure it’s still in place when you’re done.

Are there any risks to wearing the wrong size menstrual cup?

Most sizing issues come with minor risks, such as irritation and leakage.

But there is a chance of bigger risks, both with a cup that’s too small or too big.

If your cup’s too small, it can suction to your cervix, causing pain or prolapse when removed.

And a cup that’s too big can obstruct the flow of urine due to putting pressure on tissues around the vagina.

It may take a couple of tries to find the perfect menstrual cup. Not only do all brands have different sizes, but it can also be hard to work out what’s best for your body without some experimenting.

Luckily, some brands allow you to get your money back if the cup’s not the right fit. So focus on age and birth history as a starting point and go from there.


Lauren Sharkey is a U.K.-based journalist and author specializing in women’s issues. When she isn’t trying to discover a way to banish migraines, she can be found uncovering the answers to your lurking health questions. She has also written a book profiling young female activists across the globe and is currently building a community of such resisters. Catch her on Twitter.