How to Find Your Menstrual Disc Size

Menstrual discs have been around since the 90’s but they’re having quite the surge in popularity thanks to the emergence of many new reusable brands. If you’ve never used one before and want to give it a go, you’re probably wondering how to find your menstrual disc size.

Thankfully, finding your menstrual disc size is really simple, especially when compared to finding your size of its reusable period product counterpart, the menstrual cup. It definitely can feel like it takes nothing short of a PhD to understand sizing options for a cup. But no fear, menstrual disc sizing is more straight forward, not to mention, we’re here to help.

First Things First

If you are an experienced cup user please forget everything you know about picking a menstrual cup size. It’s a completely different sizing system for discs.

Disc sizing is based almost entirely on your cervix height. Unlike cup sizing, your age, activity levels, and pregnancy histories are not factors that influence the size of your disc.

Further, you should not use your current menstrual cup size to base your menstrual disc size. For example, if you are a size Small Saalt Cup it does not mean that you’ll be a size small for a Saalt Disc. Really, buying the same size disc and cup will not always end in a good outcome unless it’s coincidental.

The One Size Disc: Why One Size Really Does ALMOST Fit All

Almost every disc you’ll encounter, disposable or reusable, is about the same size. Why is that? It’s because discs sit in the vaginal fornix and for most of us, a disc in the 60-70 mm diameter range will fit.

That sure does take a lot of the stress and guesswork out of reusables. Discs are modeled after the diaphragm and the most popular, and virtually only brand making them today Caya comes in at around the same size as most one size discs, lending more credibility to the “one size fits most” debate. Discs do appear positively gigantic in size, compared to menstrual cups and especially compared to tampons. Don’t freak out though, they fold to be very slender for insertion.

When you insert a one-size or “large” disc it will stay folded until it reaches the top of the vaginal canal where it has the space to then expand into its round or oval shape. It tucks behind the cervix and in the front, tucks behind the pubic bone.

If you find it impossible to get the front side tucked, one possible reason could be that the disc is too large for your anatomy.

Who Should Pick A Smaller Menstrual Disc Size?

Smaller diameters discs are for users who have a lower cervix or for people who tried a larger disc without success. If you do have a low cervix there is still a good chance a one-size disc will work for you, but now with smaller diameter options, you can decide which you think will be a better fit for you. For low cervix folks, you will need enough room to get your disc engaged behind the pubic bone. If the disc can’t, it will not work for you. 

Disc Size and Leaks

Size can be a factor in the disc working effectively with or without leaks. If it’s either too large or too small certain combinations of actions such as sneezing, coughing, squatting, etc might disengage the disc. This happens if the disc is just a bit too large and the movement springs it out of place from behind your pubic bone, which in a full disc scenario, would cause a gush. In the case of the disc being too small, the movements give the disc room to slip past the pubic bone to cause the leak. 

If you’re experiencing these types of leaks that seem related to your disc’s size the best way to address is to look for a disc that’s slighter larger or smaller. 

Menstrual Disc Size and Comfort

Because discs are worn higher in the body and have just the rim portion making contact in the body most users find them more comfortable than cups. Discs are less likely to apply bladder pressure for the same reason. If you’ve tried a disc that did cause you discomfort or pressure this could be a firmness issue or size. Sizing down to a smaller diameter could help relieve the discomfort or pressure.

Related Resource: Menstrual Disc Firmness

Menstrual Disc Size FAQs

Can I Try A Disposable Disc To Find My Size?

Reusable discs can be quite an investment but the good news is that there are disposable discs available to try. These discs are either the Softdisc or Flex brand. It won’t matter which since they’re essentially the same product in a different color/different price. Their diameter is 69mm, in line with most of the One Size menstrual discs by, give or take, 1-6 mm.

Sort menstrual discs by diameter on our Menstrual Cup and Disc Comparison Chart.

Trying a disposable disc can at least give you an idea of whether or not a one-size or large reusable disc will tuck for you. It also gives you some ballpark understanding of whether you will like menstrual discs. The comparisons aren’t perfect – disposable discs are much firmer, more rigid, and have sharper edges. I’d be lying if I didn’t say my own first experience with a disposable disc was not great but I LOVE reusable discs. Keep that in mind if you do decide to try out a disposable. Your experience, good or bad, may not directly translate to a reusable. It’s not unhelpful, but it’s not a perfect indicator either.

Can My OB/GYN Size Me For a Menstrual Disc?

A few decades ago your OB/GYN could fit you with a set of rings they kept in their office, then prescribe you a rubber diaphragm in your size for birth control. At some point, this birth control method fell out of fashion. If you want a diaphragm your OB/GYN will either look at you in confusion or tell you to buy a Caya online that’s “one size fits most.” Diaphragm fitting rings are now antiques. While you can always ask for guidance from your OB many are simply not up to date on the latest reusable period care options or have little or no advice that is helpful. You are your own best resource in finding your disc size.

Throw A Dart, Get Lucky

The reason I love discs for myself and as an advocate for reusable products is that they’re stupidly simple. Pick almost any disc and it has a higher chance of fitting, working leak-free, and being comfortable for you compared to menstrual cups. I know a handful of very passionate followers of mine will disagree based on their experiences, but I am reflecting back on the experiences of thousands of people. There will always be anomalies in sizing guidelines but I must educate based on the majority. So, if you found out the hard way that despite all odds the size that SHOULD fit you, didn’t, that is unfortunate but it happens.

Preferences exist in the brands and styles of reusable discs that are available – I am not a huge fan of the hook or pinch to remove action since it’s messier than cups, which is why I love the Hello Disc. If you think you want a softer disc, Nixit is a great choice. Want a firm reusable disc? Flex reusable is the firmest and almost as firm as their disposable disc or Softdisc. Have a high cervix and worry you can’t reach to remove it? Hello Disc or Lumma Disc size High is a good option. Low cervix? Saalt Disc Small, Ziggy A, or Lumma Short are options for you. Want a simple average disc without a stem or tab? Cora Disc or Saalt Disc are options.