What 100, 150, 200 and 250 ml actually look like

100 ml is about 6½ tablespoons, or a third of a can of soft drink. 250 ml is a full measuring cup. Every one of our styles is rated in millilitres because that is the only unit that lets you compare a leak with a garment. This page translates the numbers into real leaks (a dribble, a sneeze, an urge leak, a full void), explains why speed matters as much as volume, and says plainly what each figure does and does not cover.

Most brands publish teaspoons, tampons or "moderate". Women on the period-underwear forums have built their own spreadsheets to convert those into millilitres; men on the prostate forums compare fluid ounces from guard packaging. The question underneath is the same: "is a cup my whole workday, or am I still changing at lunch?"

The numbers in things you can picture

The SLK8036 boyshort is rated for periods and leaks together at roughly twelve tampons' worth. The W01 full brief has a full-coverage panel for urge leaks and wider coverage.

How big is a real leak?

Clinics measure leaks with a pad test: you wear a weighed pad for an hour of ordinary movement, and the weight gain is the leak. Commonly used thresholds classify a gain of up to about 10 grams (10 ml) as mild, 10 to 50 as moderate, and over 50 as severe. Most of the leaks people describe on the forums sit in the first two bands:

• Post-void dribble: a few drops to a teaspoon, once, shortly after you finish. Well inside 150 ml, many times over.
• A sneeze, cough or laugh: typically a few millilitres to a couple of tablespoons for stress leaks. Several in a day still sit inside 100 ml.
• An urge leak on the way to the toilet: anything from a tablespoon to a large part of the bladder, depending on how far you got. The small ones fit; the large ones do not.
• Leaks after prostate surgery, weeks 3 to 8: repeated stress leaks through the day that can add up to 100 to 250 ml. That is the M96's job.
• A full void: 300 to 500 ml for most adults. No washable underwear is built for that, ours included.

Why speed matters as much as volume

A garment rated at 100 ml does not hold 100 ml if the liquid arrives faster than the top layer can pull it into the core. A period arrives over hours. A sneeze arrives in a second. That is why period underwear rated for a "heavy day" can still fail a sneeze, and why our women's styles use a wicking top layer over the absorbent core: its job is to move a sudden surge downward before it can spread sideways. The waterproof layer then runs to the leg edge, so whatever spreads stays inside the garment. Volume tells you how much a pair can take in a day; the layers decide whether it takes a surge.

Will I feel wet?

Not up to the rated capacity, in normal use. The top layer wicks liquid off the skin into the core, so the surface against you stays comparatively dry after a leak. Two honest limits. First, in the seconds after a large leak you may feel warmth before the layer has done its work. Second, once a pair has taken its capacity the surface stays wet, which is why the rating matters more than "maximum absorbency" on a label. The most common complaint about cheap washables ("the inner lining felt continually wet") is a pair that had no wicking layer, or one that had been washed with fabric softener, which coats the fibres and stops them wicking.

Does it leak out the sides?

This is the failure people describe most often with pads, guards and cheap washables: the absorbent material stops short of the leg opening, a leak spreads sideways when you sit, and it escapes at the leg. In our styles the waterproof layer runs to the leg edge. A leak that reaches the edge stays inside the garment. What that layer cannot do is hold more than the rated volume; a pair pushed past 250 ml will eventually pass liquid through, at the edge or anywhere else.

What happens if a leak is bigger than the rating?

The core saturates and the next liquid is not absorbed. You will feel wet and, past that point, the outer fabric can dampen. Nothing dramatic and nothing that ruins the pair, but it is the honest reason we list a number instead of a promise. If your leaks regularly exceed the rating, choose the next style up, or use a disposable for that situation (nights, the first fortnight after prostate surgery, a full void) and washables for the rest of the day.

Is a cup my whole workday?

For most men after the first weeks of recovery, a 250 ml M96 is a workday, because the leaks are repeated small ones that add up to less than that. For a man whose leaks are still full streams on standing, it is not, and a disposable pull-up remains the right product until that changes. For most women with stress leaks, a 100 ml P14 is a full day, because several sneezes and a cough do not reach it. The how-many-pairs guide turns this into a change schedule.

How we rate capacity

The figure on each product page is the amount the absorbent core holds in daytime use, measured on the garment, stated once and stated the same everywhere. We do not add "or more", we do not quote a separate marketing figure, and we do not rate for overnight. If we film a pour test for a style, it is the real garment and the real volume, and it is linked from that product's page.

Common questions

How much urine does incontinence underwear hold?

It depends on the pair and on how the brand states it. Ours are rated in millilitres for daytime use: 100 ml for the women's P14, 150 ml for the men's M65, 200 ml for the M66 and 250 ml for the M96. A full bladder release is 300 to 500 ml and exceeds any washable underwear.

What does 100 ml look like?

About six and a half tablespoons, a third of a soft-drink can, or a small wine glass. Several sneeze-sized leaks in a day sit well inside it.

Will I feel wet in leak-proof underwear?

Not in normal use up to the rated capacity: the top layer wicks liquid into the core so the surface stays comparatively dry. Once a pair has taken its capacity, it stays wet, and fabric softener stops the wicking layer working, which is the usual cause when a pair feels wet after a small leak.

Does leak-proof underwear leak out the sides?

Ours has the waterproof layer running to the leg edge, so a leak that spreads sideways when you sit stays inside the garment. It cannot hold more than its rated volume; past that, liquid will pass through.

Can it hold a full bladder release?

No. No washable underwear does, and any brand that implies otherwise is inviting the reviews that follow. For a full void, heavy nights or the first fortnight after prostate surgery, use a disposable and switch to washables as the volume drops.

How big is a normal bladder leak?

Clinic pad tests commonly classify up to about 10 ml in an hour as mild, 10 to 50 as moderate and over 50 as severe. Post-void dribble is a teaspoon or less; a sneeze leak is usually a few millilitres to a couple of tablespoons; an urge leak varies widely.

Capacity figures are measured daytime ratings for each garment. Pad-test thresholds are commonly used clinical categories, not a diagnosis. This page is general information, not medical advice.

Written by Laura Hopson, founder of Maven Nove. Last updated 10 September 2026.