Menstrual Cups

Squish Test Results

People often want to know how squishy a cup is compared to other cups.  Which is sometimes hard to judge.  This “squish test” of often done by taking 2 cups and pressing them together, like this:


This shows that the cup on the top has flattened more than the cup on the bottom, so the top cup is presumably made from a softer silicone, because it compresses more than the other cup.

However, holding the cups on top of each other like that, is not an accurate test.  I have noticed in doing this myself, that if you have 2 cups with a similar degree of squishyness, the bottom cup will always flatten more.  It seems there is more pressure on the bottom cup than the top cup.  Also when you squash 3 cups together, the centre one squishes more.

So to get a more accurate indication of which cup is softer, you really need to compress 2 cups, from the sides.  So that there is a more even pressure on both cups.  Like this:


It also has some degree of human error – as you could press more on one side than the other, or press in different areas of each cup (eg more towards the rim on one, and more towards the body on the other)

To take away any human error…. and be able to get results a bit more “scientifically” – I tried to work out how I could measure the amount of force needed to compress the cups, to calculate the softness that way – but finding an inexpensive way to test that way was not possible.  So I decided that I would do the side by side squish test using a caliper to hold the cups in place.


This does the same thing as holding the cups in my hand, but should have a more even pressure on both sides, since the cups are being placed between the arms of the caliper.  I have also locked the caliper to 50.00 millimeters between those arms, so that each cup test is compressed by the same amount each time.

As you can see in the image above, when compressed to 50mm, the Miacup (right) does not compress as much as the Brandless Moon-stem cup (left).  So this shows that the cup on the left is made from softer or “Squishier” silicone.


My Squish Test Results

To be able to compare the relative squishyness of the cups to make a list, without having to test every cup against all the other cups, I have measured all the cups against one cup – the Lunette.

As in the picture above, all these test results are done by setting calipers to 50mm, putting a Lunette and one other cup together between the arms of the caliper, and measuring how compressed the rim of the cup I’m testing against the Lunette is (measuring from the outsides of the rim, to account for the fact the cups have different thicknesses of rim).  This compressed rim measurement is in brackets after the brand name.

So the cups at the top of the list, with the smaller number in brackets – are “squishier” or “Softer”.  Cups towards the bottom of the list, are “Firmer” or “Harder”

Now, this is not a perfectly accurate reading, I do have to try to hold the cups straight while in the caliper, and that can make it possible for a slightly inaccurate reading – but I think it’s about as accurate as I can get with a home-made measuring system.  However it can be used to give an indication of relative “squishyness” of the brands.

(If anyone has any particular requests as to which cups to compare together – of cups that I own [are in this list], comment here and I can compare them for you.)


Large Sizes
All Large size cups (except the Luv Ur Body, which I used the “medium” size since it was closer in size to the Large sizes of other brands, and the single sized cups) tested against a Large Lunette.

  • Aneer (18mm)
  • (Nameless ebay moon stem cup) – (20mm)
  • Gaia Cup (21mm)
  • Lunacup (21mm)
  • Miacup [old] (21mm)
  • Sibell – (21mm)
  • Cup Lee (22mm)
  • Juju (23mm)
  • Mami Cup (23mm)
  • Sckoon (23mm)
  • OrganiCup (24mm)
  • Fleur Cup (24mm)
  • Lena Cup (24mm)
  • Lily Compact (24mm)
  • Vcup [one size] (24mm)
  • Mooncup UK [new] (25mm)
  • Ruby (25mm)
  • Claricup (25mm)
  • Eco-Cup (26mm)
  • Femmecup [new] [one size] (26mm)
  • Luv Ur Body (26mm)
  • Anytime (27mm)
  • Lady Cup (27mm)
  • Lily Cup (27mm)
  • MeLuna [Classic] (27mm)
  • Mpower (27mm)
  • Blossom Cup (28mm)
  • Femmycycle (28mm)
  • Lunette (28mm)
  • MenstroCup (28mm)
  • Mooncup uk [old] (29mm)
  • Yuuki – [new] (30mm)


Small Sizes
Tested against a Small Lunette – using all Small, or single size cups.

  • iClean (23mm)
  • Cup Lee (24mm)
  • Si-bell (25mm)
  • Keeper (26mm)
  • Diva [old] (26mm)
  • Luna cup (26mm)
  • Femmycycle (26mm)
  • MenstroCup (26mm)
  • Luv Ur Body (27mm)
  • Sckoon [prototype] (27mm)
  • Juju (27mm)
  • Lunette (27mm)
  • Claricup (27mm)
  • Yuuki [new] (27mm)
  • Lily compact (27mm)
  • Femmecup [new][one size] (27mm)
  • Bassrose [one size] (28mm)
  • Eco-cup (28mm)
  • Lena Cup (28mm)
  • Vcup [one size] (28mm)
  • Blossom Cup (29mm)
  • Femmecup [old] (30mm)
  • Mooncuk uk [old] (33mm)

My “new” MeLuna was from 2011, I assume it is a “Classic”, but it’s HEAPS softer than their old cups.  The “new” Yuuki I’m not sure which version it is, probably the “classic”


— disclaimer —
Now, I would like to mention that when I get new cups in, I have to compare them to the old cups I have to know where to rank them, and I’m not sure if silicone changes softness over time (when stored in a dark box and not used – as my samples are). So that may affect my ratings.

Cups apparently get softer the more they are used (particularly through repeated boiling) – so my cups that are used once or twice then put in a storage box, will probably not be as soft as a cup that is used by someone regularly.

Please note that I can only test the cups I actually have – so this is a list of the cups I own.  Please do not ask me to test any cups not on this list!  I can’t rest what I don’t physically have.

I will update the list whenever I obtain a new cup.


February 13, 2015 - Posted by | comparisons, reviews |


  1. Hi Obsidian^^

    For the large FemmyCycle, could you test both the regular and low cervix ones ?

    Comment by Quitterie | February 14, 2015

  2. The only difference with the low cervix model is the shape of the ring stem, on the low cervix one the ring is flatter and wider

    “Regular” = 36mm diameter, 43mm length without ring, 63mm with ring.
    “Low Cervix”= 36mm diameter, 43mm length without ring, 50mm with ring

    So I tested it, and yes, it appears to be a 28mm compression too.

    Comment by obsidian | February 15, 2015

  3. Hi! Do you wich one is firmer? if Meluna Sport or Yukki Classic? (sorry for bad english)

    Comment by Marcela Braga | March 1, 2015

  4. I can only test the cups I physically have. MeLuna won’t send me a sport one…. so I cannot check it.

    Comment by obsidian | March 1, 2015

  5. Thanks for inventing this method! Much more solid than doing it with one’s hands 🙂

    I unfortunately don’t quite understand how to read your results. So you squished the two cups to 50mm in total and then determined how many mm the tested cup takes? The rest of it being taken by the Lunette? Then why in the small cups list you have the Lunette listed as 27mm?

    Also, could you please add the small Si-Bell to the comparison? Thanks!

    Comment by Monika | April 10, 2015

  6. Hi! I’m 30, I never gave birth, I own a small DivaCup and I have a sensitive bladder so I find it too stiff for me. Also, I just can’t stand the feeling of the cup popping out inside me when I insert it and the feeling of succion when I remove it (I’m very sensitive!). I think my cervix is not low but I can’t say for sure. I think I’d need a cup that is narrow, very soft and easy to grip. Which brand would you recommend? I read that CupLee and SiBell could be good options?
    Thanks a lot!

    Comment by cup holder | April 14, 2015

  7. To read the results basically just look at the rankings….. the lower the cm score, the “squishier” the cup is.

    The fact they are tested with a Lunette doesn’t really mean anything, I just needed something to measure relative compression against, and I figured I’d use that cup.

    So a cup that compressed 21cm is softer/squishier than a cup that compressed 25cm – because the softer the cup, the more it will compress.

    The small cup listing for the Lunette was a small Lunette squished with the small Lunette I tested the other cups with. (Just as the large Lunette was tested with another Large Lunette) – I have more than one of each size Lunette so I was able to test them against themselves.

    In this comparison chart you can’t compare squishyness of small cups to large cups – because the smaller diameter of the cups means they don’t have to compress as much to fit into the 50mm space I used for both tests. Which is why overall their scores are higher than the Large cups. You can only compare Small cups against small cups.

    Although I do often find the smaller size cups feel a little stiffer than the large ones, I think that is because there is less rim.

    If you want me to test squishyness of a particular small cup compared to a large one, I can do that.

    Si-bell small is 25mm 🙂

    Comment by obsidian | April 16, 2015

  8. I am unable to give recommendations on cups I’m sorry.

    However I do quite like the Si-bell. I have tried the Cup Lee, and I did like that, although I don’t like that stem style, so would personally prefer the Si-bell as I find that stem more comfortable and more grippy.

    With opening the cup, try to release the fold slowly. When you see videos of people showing the folds, often they just release the fold quickly and let it “pop”, I find if I do that, it immediately gives me cramps. But if I release the fold slowly, it is fine.

    Comment by obsidian | April 16, 2015

  9. Hi, I just found your website and it’s extremely helpful. I’m 30 and never given birth. I’m currently using the Lunette Small and having a leaking problem every month. I’ve confirmed it’s in properly and seals, but it seems that once I start moving around it leaks. Do you think I could benefit from a firmer cup or a larger cup? Any recommendations would be so helpful. Thank you!

    Comment by Tiffany | December 16, 2015

  10. I’ve used my small lunette for several years. I found that it worked well but put a lot of pressure on my urethra. Then I had a baby and realized that the pressure was alleviated, but the cup sometimes overfilled, sometimes tilted, and removal became painful because of episiotomy.

    So I need a cup that is softer at the rim, a little wider and bit higher capacity. I decided on the gaia small (which is softer than the large)

    All of this is to say: Thank you for providing the measurements and comparisons I need to make an informed choice. 🙂

    Comment by Ania | December 19, 2015

  11. I’m not able to give recommendations, but the usual cup size recommendations are that women over 30 should use the larger size cups, so that could help you.

    Comment by obsidian | December 20, 2015

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