Quick answer

Your menstrual cup size depends on your flow volume, cervix height, and whether you've given birth vaginally. For most first-time users with a medium flow and average cervix, a standard size cup works well. If you have a heavy flow or a low cervix, look for a larger or shorter cup.

How flow and cervix height affect cup size

Flow volume determines the cup's capacity. A light to medium flow usually suits a smaller cup (around 0.5 oz or 15 ml), while a heavy flow needs a larger cup (0.68 oz or 20 ml). Cervix height is just as important: if your cervix sits low, a shorter cup prevents discomfort; if it's high, a longer cup makes removal easier. You can check your cervix height by inserting a clean finger during your period and feeling how far up it is.

Age and childbirth considerations

If you've given birth vaginally, your pelvic floor muscles may have changed, which can affect how well a cup seals. Many brands recommend a larger size for those who have had a vaginal birth. Age alone isn't a factor, but pelvic floor strength can decrease with age, so a slightly larger cup may provide a better seal.

Decision rules for your first cup

  • Flow volume: Light to medium flow: choose the smaller cup (0.5 oz). Heavy flow: choose the larger cup (0.68 oz). If you soak a pad every 3-4 hours, go larger.
  • Cervix height: Low cervix (finger touches cervix within 1 knuckle): short cup. High cervix (finger reaches cervix after 2+ knuckles): long cup. A cup that's too long can press on your cervix and cause discomfort.
  • Vaginal birth: If you've given birth vaginally, a larger cup often provides a better seal due to changes in pelvic floor tone. Start with the larger size unless you also have a low cervix.

Product facts that matter

  • Satisfyer Menstruation Cup - Green: The Satisfyer Menstruation Cup is made from soft, medical-grade silicone and includes two sizes (0.5oz & 0.68oz) to suit both light and heavy flow days. Having both sizes in one set lets you switch between light and heavy days without buying a second cup, saving money and reducing waste.
  • Obsessive - 2 Piece Set L/XL Red: The Obsessive 2 Piece Set L/XL Red is a cupless lace bra and crotchless thong set designed for seduction, not menstrual protection. This set is not suitable for period care. Use it for intimate play or lingerie layering, but never as a substitute for a menstrual cup or pad.

Who should choose which size

Best for

  • First-time users with a medium flow and average cervix height: standard size cup (0.5 oz)
  • Heavy flow or post-childbirth: larger cup (0.68 oz)

Not ideal for

  • Anyone with a very low cervix: a standard cup may be too long and cause pressure or leakage