for Better Menstrual Options

New Zealand's

One stop shop for alternative menstrual products

Kia Ora! Welcome to EnvironMenstruals.

How to choose a cup

You may have notices in reading through the product information for my menstrual cups that most brands come in 2 sizes each (Femmecup is one size only and MeLuna has 8 sizes), yet they're not the same 2 sizes. While the numbers and options may seem a little overwhelming, don't dispair, there's a good reason for it. No 2 bodies are created equal, so no 1 (or 2) cups will fit every vagina the same. Of course, even a cup that doesn't fit perfectly will work well, so you may be quite happy to buy on aesthetics or price alone. Here are some simple steps to finding a good cup for you.


  • 1) The first thing you need to know is where your cervix sits when you are menstruating. You need to find this by 'hunting it out' during your period. The cervix is the entry to the uterus, which is commonly pictured as the end of the vagina. In reality it doesn't sit at the end of a long tube, like the bottom of a glass; it's more like on the wall at the back of a long cave, or hiding up in the corner near the roof. You can find it by inserting a clean finger (your longest one is best) inside you vagina while you have your period. Your cervix will feel like a slightly firm, round lump with a small dimple in the middle. Many women describe it as feelinglike the tip of their nose. Finding it on different days can be useful, as it may move around.


  • When you've located your cervix, you need to measure how far in it sits...how far in was your finger? This tells you something about the length of cup you need. You need the whole body of the cup to sit inside you, but not so far in that you can't reach it. Do you need a short cup that you can stim the stem from, or a longer cup with a long stem?
  • Menstrual cups must sit below the cervix, so that they can catch the blood coming from that wee dimple you felt. If you get toolong a cup, you may find that it needs to stick out, or that you put it too far in, so it sits beside, rather than below, the cervix. If you have a very low cervix (under 4cm) you can still wear a cup, I'll tell you how to work that out soon.


  • 2) Now you need to think about the capacity of the cup you're going to get. How much do you bleed and how often are you willing to change the cup? Thinking about the products you already use, you should have a reasonable idea of how heavy your period will be in each day. If you use 1 regular tampon (or a Tampax super) every 6 hours, that's a flow of about 9x2, or 18 grams per 12 hours, which means you need to catch 12 ml per 8 hours (that's the longest you should wear a cup without emptying and washing it). So if you want to only check and empty it in the morning, evening, and before bed, you'd want something with a capacity of about 12 ml. Smaller will need changing more often, larger will allow you some room for variation.
  • Super (or the Tampax superplus) have a capacity of about 12 grams. Light/mini tampons are usually around 6 grams. Pads are a little harder to work out, as they don't have to apply restrictions on their absorbency.
  • How does this tie in with the length? If you have a very low cervix but need a larger capacity cup, you may find that a larger and longer cup will work, as it will sit around your cervix (cervix inside the cup). This is something of a trade off though, as it will be taking up some space in the cup.
  • It is a good idea to err on the side of a lower volume if you are planning on having only one cup, as using a larger cup than you need on light daysmay result in more bacterial growth as there is more air available. If you are planning to have 2 cups, then you might want to pick a larger volume one for heavy days and a lower volume one for light days, or 2 low volume cups.
  • 3) How wide do you get? That depends a lot on your pelvic floor muscle tone and how familar you are with inseting and removing objects from that area. In it's natural state the vagina is closed; that is, the walls sit in contact with each other. They like to be in this position, so the size is not so much about weather you need a bigger cup as it is about whether you can accomodate one that size. If your muscles are prone to gripping, or aren't able to relax around teh cup, you may find that a larger cup will leak as the rim puckers to fit.
  • Women who have given birth to children will have very flexible vaginal walls and a slightly larger cervix (usually), so will usually be comfortable wearing a larger diameter cup. They may still want to wear a smaller one, and they can, if their pelvic floor muscles are strong (do your kegal exercises!).
  • Teenagers (especially virgins), and women (or FtM men) who have not had a lot of vaginal penetration will usually find a small cup more comfortable. This is especially important during insertion and removal.
  • Some women find that they can't wear the same diameter cup right through their period, as they become more tender or their muscles tighten up.
  • If you do a lot of yoga, pilates, weight lifting, or other core strengthening exercies, you may find a smaller cup works better for you too.
  • 4) Here's where you put it all together...  THIS FLOWCHART (http://www.environmenstruals.co.nz/documents/flowchart.pdf) will help narrow down your options. For example: following the chart, if your cervix is high, you bleed very heavily, you're 13 and you've never had sex, you want something narrow but long in the body witha  good capacity. Somethign like a small fleur, or small/medium meluna (new shape) might suit you. If your flow is light, a shorter cup with a longer stem will probably suit you too.
  • This spreadsheet might also help you work out the combination for you. Spreadsheet
  • You'll notice that there is such a huge variation in sizes that a small cup in one brand may be comparable to another brand's large in many ways. You can use these similarities to find a good combination of shape and dimensions for you.
  • 5) Hoop skirt or narrow bodied? Your capacity calculations may have solved this one already. Hoop skirt shaped cups have a larger capicty than narrow bodied cups. However, narrow bodied cups are better if your bladder is sensitive to pressure (post prolapse), and if you think you may feel a wider based cup. Narrow bodied cups have a larger 'lip' at the rim, which helps to create a good seal, but does make the cup larger for insertion and removal.
  • 6) Softness - Soft cups are harder to pop open, but easier to slide in and out (they have more give against the muscles of the vagina entrance), and for some women are more comfortable to wear. They can be more prone to leakage than firmer cups due to not openning fully. Firm cups pop open easily, so are great if you're still learning to get them in and out, but that same stiffness can leave a novice a bit sore at first. They are less likely to be squished by the muscles, so may be felt during some activities.
  • 7) Colour and cosmetic details, other concerns and price. What shaped stem do you want, is printing on the cup ok? Do you want measuring lines? Do you want a pretty colour? Do you have a limited budget? Do you like that particular pouch? Does business ethics or material used matter to you? Once you've picked the size and shape, you can consider other issue in determining which cup to buy.
  • 8) Which one do you like the look (and feel) of? It seems to be that if you're trying to decide between brands, you may be drawn to one more than another because you like the shape or texture. Don't dismiss that - anecdotally, it seems that we subconsciously know what will be comfortable, so trust your gut.

Do you buy a lower priced cup now that you know isn't your ideal so you can start saving for your 'goldlocks' cup? Do you buy 2 cups so you can always be sure to have 1 that's sterile? or may 1 for heavy days/nighttime and 1 for light days and spotting, or even 2 sets of 2? It's up to you and your budget really.


I hope this helps.