Put A Cup In It

Choosing a Menstrual Cup Size | How To Pick The Right Size

With so many choices out there and the conflicting sizing guidelines from each brand it’s confusing to pick a menstrual cup size. But what are the sizes and which size menstrual cup will fit you best?


Menstrual Cup Sizes

Most often menstrual cups come in two sizes but some brands offer three. A small number of brands offer more options that are specialized including “low cervix” sizes. The most common option is of a “small” and “large” and while there isn’t a sizing standard you can expect that these brands size their smalls anywhere from 35-43 mm and the larger sizes around 43 mm- 48mm in diameter at the rim of the cup.

menstrual cup options

If you go by the guidelines issued by most brands of “under 30 years old and haven’t given birth- you’re a size 1 and over 30 or you have given birth, which includes any full term delivery, you’re a size 2” one brand’s smallest size can be the size of another brand’s large! Other brands like to size cups by the amount of fluid they hold and tell you to pick a larger cup if you have a heavy flow, a smaller cup if you have a lighter flow.

If we had to pick, selecting a size based on age+birth history is more accurate than selecting a cup based on flow. In the case of a person who is over 30 but who has a lighter than average flow it’s very possible if they select the smaller size for this reason and that cup isn’t wide enough in diameter to stay in place it will cause frustration for the user as the cup slips down. We stress that this is NOT a perfect guideline but is a helpful place to start when you haven’t yet tried a menstrual cup but trust your gut, always, when making your choice.

Choosing a Cup Size Based on Length

menstrual cup sizes

Before you consider any other factors when choosing your cup forget the “size” and start with length. A cup that is too long to fit completely inside your vagina will not work for you (yell it for the people in the back!) But how do you know how long your vagina is? You need to measure where your cervix is during your period and this can be done by taking a clean finger, inserting, and locating your cervix. It should feel like the tip of your nose. If you can’t find it that may mean you have such a high cervix it can’t be reached, this is good! That just means you can use practically any length of cup you’d like. Once you find your cervix place your thumb against your finger to mark all the length that fits inside, then remove your finger and measure to where you placed your thumb. A precise measurement is preferred to the knuckle method often depicted in sizing graphics because our fingers are different lengths.

Related: Find a Low Cervix Menstrual Cup

Choosing a Cup Size Based on Diameter

Now that you know your cervical height we can begin the task of choosing your cup’s “size.” Generally the sizes refer to the diameter of the cup and have little to do with the length, though smaller sizes are most often shorter than their larger counterparts but not always. See? Confusing!

It is true that your pelvic floor muscles tend to relax with age and/or after you’ve had a full term pregnancy. The sizing guideline  “given birth” has nothing to do with you delivering vaginally and just means your body has prepared for labor and muscles are looser after. If you delivered vaginally forget the notion that your baby blew through your vagina and left a cave behind; your vagina does stretch but it returns to a normal size. You can use that guide to decide if you are a smaller cup or larger cup but the fact is you know your body best. If you feel like you have a petite vaginal canal but you’re over 30 or you’ve had a baby, you might still use a size 1. If you know you do exercises that work the pelvic floor muscles or perhaps you have done pelvic floor therapy and understand you have a stronger pelvic floor then you can also select a size 1. For more information about pelvic floor therapy visit our friend, The Down There Doc, or look for a pelvic floor therapist near you. The difference between most sizes is pretty minimal so if you’re in doubt remember your vagina stretches but cannot “clamp down” to keep a cup in place. With that in mind perhaps a size 2 is a safer bet.

Choosing a Cup Size Based on Capacity

Now we come to the capacity factor. Most smaller cup sizes hold around 25-27 millileters, most larger cups hold around 30 milliliters. Unless you have a very very heavy flow don’t factor the capacity into your sizing option at all. Cups hold so much more than tampons that the average person won’t fill a cup in a 12 hour timeframe. It’s just a non issue to pick a cup based on capacity when the length and size matter more for the fit. That being said if you are a very heavy bleeder you can find cups with higher capacities but you will still want to account for their length. The higher capacity the cup has, often the larger it is in both diameter and length, and you need to make sure it will fit you before picking based on capacity alone.

Related: Compare high capacity cups

Picking The Most Accurate Size Cup


To make this all even more confusing I want to remind you that each brand has their own idea of what their small and large sizes are. For example, the small Super Jennie is the same diameter as the Fun Cup and Lily Cup brand’s larger size cup. It isn’t straightforward which is why using our menstrual cup comparison chart to sort by measurements such as diameter, length, or capacity is the most accurate way to find a cup, but also advanced for someone who has yet to try a cup. If you’re brand new just take our menstrual cup quiz and start with the list of recommended cups we provide you based on your answers. Knowing your cervical height is important to getting the most accurate quiz result but we also factor in what we know to be an average and point you there if you don’t know.

38 Responses

  1. could you make the picture of the various sizes and brands larger, please? I am almost 40 and always used slender ob and carefree small pad with wings. I was really sad when they stopped carrying them. They should not just be advertised based on age but size. Even the pink always ultra thin and slender are not as small as carefree. The menstrual cup size one hurt so bad I WAS praying to God for help to get it out. it looks like they have a zero but still scared to try it. Another 40 year old told me the same. Both of us are fit and never had children. Teen and smallest are still best for me. It is painful using a large tampon much less a ring or cup!

    1. I agree with you that they should be advertised by size. I’m in my 30’s and have had 5 children so I picked the largest size and it hurt so bad putting it in and won’t open fully no matter how hard I tried. I can’t get my finger between the cup and my vaginal wall to try and “pop” it open like the instructions suggest. There’s just not enough give there and it’s incredibly painful. I’m going to try a smaller size tomorrow. I’m so irritated that I wasted money on the wrong size.
      I was as relaxed as I could be, too.

  2. Why do they advce based on age ad medical history together? I am way above 30 years old, have never been pregnant and also never had any kind of partnered sex. Yes, sexually inactive adults exist.

    1. Sexual activity isn’t a factor as it doesn’t actually affect your vaginal width, it only affects your hymen if anything. As you get older your pelvic muscles lose tone and your vagina widens whether you’ve had sex or not. So age and having given birth are the biggest factor in vaginal width, sexual activity doesn’t actually factor in at all, younger people have strong pelvic muscles and thus narrower vaginas ( unless they have a health condition) and are more likely to be virgins than an older person, but that’s just correlation not causation.

      1. Sort of. Sexual activity does not have a permanent effect on vaginal width. If anything, the muscles may be more toned in someone who is… well, using them. And going further, as this article (and countless medical studies and experiences of cup users state) childbirth generally does not permanently change the width (exceptions being… birth injuries, sometimes advanced age, multiple children in a short time period, etc.) and even then it’s not usually extreme. Sometimes there are increases in length toward the back of the canal (around the cervix area) but they are not likely very noticeable. An 18 year old who has never been sexually active could need a larger cup size than a 35 year old who has delivered two children vaginally. It’s not that simple and sometimes there is some trial and error before you can find a cup that fits comfortably. I wish more companies were more open minded in their descriptions of sizing! That’s why I found this site very helpful.

        The other factors of recent childbirth (usually first 6 months) or age (usually around peri-menopause) or weight changes (generally, weight gain/obesity) tend to be in the middle area of the canal and the good news with that is… that is where you have the most ability to retrain/strengthen the muscles if needed.

        When all the largest widespread studies were combined, there were not found to be significant differences in width/size of vaginas based on age, childbirth or pregnancy history, height, weight, sexual activity, or really… anything else. Rather it was found there is some natural variation (about a 1 inch diameter from the “largest” to “smallest” person but most people were within less than one half inch difference) but also physical activity level is a factor. I know most people are surprised by that.

        There are so many misconceptions that women are made to internalize about their bodies and that should really change! These old beliefs were not based on scientific findings and now we know better, it’s important to challenge these statements. Women were made to feel “used” or “broken” after becoming sexually active, having children, aging, etc. in order to control social behaviours… but the truth is, that’s not how it works. 🙂

    2. I am 39 and have never had sex or given birth I was so flustered trying to decide if a 1 or 2 would fit!

  3. I am 24 years old.
    Never used a tampon or cup.
    Never had sex or gave birth.
    Thinking of getting a pixie cup. Should I get a small size? or large?

  4. Can it be use for after delivery bleeding or we should just stick to pad.i always have heavy flow after delivery and it always so gross.what size is suitable to use for after delivery.am presently pregnant and am thinking of suing it after delivery since it hold much more than pads.

    1. Hello,
      I don’t think it would be appropriate to use for postnatal bleeding. Probably better to let your vaginal cavity heal before inserting anything into it.

  5. m 26 years od having 2 kids but delivered by c. section.. 1st time i use large cup… it wasn’t pop open….now what should i do….can i switch to medium size…?

    1. Hello, yes, I think you should start with a small. Even with a heavy flow a large may be more difficult to insert if you have never had sex. But perhaps you will need to empty it more often.

  6. Hello,
    I am 23 years old and have never given birth. I purchased my first menstrual cup a few weeks ago (LaliCup size medium). My cervix height is a few mm longer than the cup. The cup fits fully inside my vagina and opens properly, but it gives me some discomfort around my cervix area (but no actual pain). Could this be caused by the cup softly pushing against my cervix, or is it normal to experience some discomfort the first few times using a menstrual cup? I generally like the Lalicup, but would the small size be more appropriate for me than the medium size? I have a normal to heavy flow.

  7. hi im 25 I’ve had sex no pregnancies.I bought the lunette cup size 1 and it was fine the first time I used it but this past month I found that it leaked and I tried to make sure it was on right, and that there was suction and it was on correctly but it somehow still leaking. I also found myself having to empty it out more often does it mean I need a bigger size?

  8. Can someone please help me im 27 have two kids I don’t know if to get small or large cup I’m really stuck

  9. I am 19 years old, have never been pregnant, and have an average to high cervix. I took the quiz and it recommended the Saalt Soft cup but I do not know which size to get. I was in-between the Dive Cup and the Saalt cup and was leaning more towards the Diva Cup because the actual cup part is longer. I want to go with the Saalt Soft for it being more flexible but I do not know. If you would be willing to give me your opinion it would be greatly appreciation.

    1. I have the saalt soft cup and I’m really bummed (cause it wasn’t cheap) cause I think I’m going to have to try a smaller one. It’s fairly large and it seems like no amount of turning and wiggling once it’s in helps it to fully open and seal off. I’m 31 and have had 4 babies but I am fairly small.

    1. There are some great petite cups that are usually good for younger people. The organicup mini, Hello XS, teen cup from Saalt, etc. If you sort by diameter on our chart putacupinit.com/chart look for cups similar in size to the organicup mini in diameter for a good start

  10. Hi,
    Is there still a website where menstrual cups can be bought and sold, please?
    I would like to have the web address, please.

  11. Im 36 years old and have 3 teens my Menstrual is heavy tmi now but according to my fiance im very tight and it dose take about 15 minutes to get in he’s not huge but definitely not small i know sounds crazy but tried to measure his with toilet paper roll tip was too big so anyway according to him I’m still tight yet if and when I sneeze or cough hard something ill pee so its hard to figure out which cup is for me and I was wondering would an obgyn dr know or not which cup is for me?

  12. I had sex many times but never get pregnant
    Never gave birth to a child
    What size should i take because my vaginal size is big??
    Suggest plzz!!!!

  13. I have been using the Mooncup size B for a few years now. On my heaviest days, I need to empty the cup every hour. I am not even joking.. it becomes quite difficult to go anywhere. So ironically, I go back to using pads on those days so that it is easier to remove and change in the public(office) bathrooms. This is why I have been considering getting a larger cup – either the Mooncup in size A or the Lunette size 2.
    I am under 30, have not given birth and have an average pelvic floor height. Should I go ahead an try a larger cup? Or would it really not make any difference considering only 2ml larger capacity?

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