Menstrual Cup Size: How to Find Your Best Fit

Too large and it feels uncomfortable. Too small and it may leak. The right size is the difference between "never again" and "how did I ever manage without this?"

Here is how to choose your size without endless trial and error.

Why Size Matters

A menstrual cup needs to create a light seal so it can stay leak-free. If it is too small for your body, it may not open fully. If it is too large, it can feel uncomfortable.

The most important factors are:

Flow strength - how much you bleed during your period

Pelvic floor strength - sport, birth, and age can all influence the pelvic floor

Cervix height - a low cervix usually needs a shorter cup or a trimmed stem

Size S (Small): Who Is It For?

Recommended if:

You are under 30 and have not had a vaginal birth
You have a light to medium flow
You are very active or have a strong pelvic floor
You are a beginner and want to start with a smaller size

The smaller cup is easier to insert and a good first choice.

LUNACUP size S (size 1): Classic 15 ml, 40 mm diameter · Evolution 24 ml, 43 mm diameter.

Size L (Large): Who Is It For?

Recommended if:

You are over 30
You have had a vaginal birth
You have a heavy flow, for example a tampon fills in less than 3-4 hours
Your pelvic floor is weaker

The larger cup holds more and can sit more securely with a looser pelvic floor.

LUNACUP size L (size 2): Classic 20 ml, 45 mm diameter · Evolution 28 ml, 47 mm diameter.

How to Check Cervix Height

It sounds more complicated than it is:

Wash your hands

Squat or place one foot on a raised surface

Insert your index finger into the vagina until you feel a round, smooth surface with a small dip in the middle - that is the cervix

Notice how far your finger went in

Result:

Finger does not reach the second knuckle: low cervix - choose a shorter cup or trim the stem
Finger reaches the second knuckle or more: medium to high cervix - standard length usually works

LUNACUP Classic is designed so the stem can be fully trimmed if needed without affecting the function of the cup. Never shorten the LUNACUP Evolution stem.

If You Are Between Two Sizes

Choose size S if:

You are under 30 and have not had a vaginal birth
You are very active and have good pelvic floor tension

Choose size L if:

You are over 30 or have given birth vaginally
You are unsure and prefer more capacity

Frequently Asked Questions

Does a C-section mean I need the larger size? Not necessarily. A C-section itself usually affects the pelvic floor less than a vaginal birth. Age and pelvic floor tone matter more here.

Can I use a menstrual cup if I have never had vaginal sex? Yes. Menstrual cups can be used by people with different bodies and experiences. The hymen is not a fully closed membrane. Go slowly, choose a comfortable size, and stop if something hurts.

What if the size I chose does not fit? Frequent leaking can mean the cup has not opened correctly or the size is wrong. Try different folds first. If you still have problems after 2-3 periods, switch size.

Is LUNACUP helpful if I need easy emptying? Yes, LUNACUP Evolution. Its integrated valve is especially practical for heavy flow because you can empty the cup without removing it.

Discover Your LUNACUP

The LUNACUP menstrual cup comes in sizes S and L. LUNACUP Evolution adds a drain valve: empty it without taking it out.