Menstrual Cup: What size?

MyCup-About-What size menstrual cup do i need


Please keep in mind that the body changes whilst menstruating: the cervix can move and at times you might need two sizes of menstrual cups to work with your active cervix! 

Before your period your uterus relaxes and drops you cervix down lower into your vagina, the entrance to the cervix (os) opens and the blood flows into the vagina. (This may also vary from person to person)

Because of this you may find that your cervix is lower on days 1-3 of your period, requiring a smaller cup. Then on days 3+ you may need a larger cup as your uterus tightens again, lifting your cervix up and slowly back into its normal position.

Take in consideration the following possibilities as well, you may need to call us on our helpline to ensure you are getting the right size cup to cater for any of the following conditions:

  • Prolapse (firmer cup),
  • Very Low Cervix (can feel it just inside the entrance to the vagina)
  • Very High Cervix (cannot find it)
  • Sensitivity (softer cup)
  • Endometriosis (heavy periods and a softer cup)
  • PCOS (heavy periods)


(remember cup width also needs to be considered - below)

The most important factor in choosing the right cup is knowing your cervix height.

If you want to be absolutely sure about your cup size you need to check the height of your cervix every morning during your entire period. Then you can work out which cup would be best in terms of height. But you still need to be sure about the cup width (see below as tampons give a good idea of which cup width you should use)

  • My Cup Size 1 (cup part only) height: 44.5 mm
  • My Cup Size 2 (cup part only) height: 51 mm


(remember cup height also needs to be considered - above)

The general rules of thumb as follows:

  • Small and Regular Tampons → My Cup size 1
  • Regular Tampons only → My Cup size 1
  • Regular and Super Tampons → My Cup size 1 and/or My Cup size 2
  • Super Tampons only → My Cup size 2


My Cup Size 1
Capacity to breathing holes: 22ml
Capacity to rim: 29ml
Length including stem: 62mm
Length of cup only: 44.5mm
Length of stem only: 17.5mm
Width of diameter: 42mm


My Cup Size 2
Capacity to breathing holes: 31ml
Capacity to rim: 40ml
Length including stem: 67mm
Length of cup only: 51mm
Length of stem only: 16mm
Width of diameter: 46mm

Info from: