Custom fit condoms

An ill-fitting condom makes breakage and slipping more likely, according to Durex. If it's too loose, it can come off during sex. ONE's research found that standard condoms pinch 50% of people, hang loose on 30%, and run long for 91%.

You can usually tell a bad fit when you feel one. Pinching, rolling up or breaking points to a condom being too small, while slipping or bunching up points to one being too large, says Condom Depot.

Sizing is based on measurements taken while erect. Girth is how far it is around the penis, taken at the widest point, normally a little below the head (Okamoto).

1. Get fully erect first, since the sizes assume erect measurements.
2. Take a soft tape measure, some string or a strip of paper and wrap it once round the widest part of the shaft.
3. With string or paper, pinch where the two ends meet, then straighten it out against a ruler to get the length.

The figure printed on a condom box is its nominal width. That means the width of the condom lying flat and unstretched, which works out as half its full circumference (Mister Size). In the EU, packs have to show this number. The standard permits the true width to be up to 2 mm off the printed figure in either direction.

MyONE comes from ONE Condoms and offers nine widths. It's built for all the people ONE says can't wear a standard condom comfortably. ONE recommends a condom that's slightly tighter than your penis to keep it from moving around.

No tape measure? ONE has a quick trick using a toilet paper roll. It found the inside of a standard roll measures about 5 inches around, close to its MyONE 55 size. Rolls differ from brand to brand, so take this as a rough guide only.

Each MyONE size takes its name from the nominal width of the condom, which ONE gives in millimetres (ONE). The range starts narrow and widens as you go:

Each size's number is its width in millimetres, so MyONE 45 is 45 mm wide. The sizes run 45, 47, 49, 51, 53, 55, 57, 60 and 64.

MyONE 53 is the same width ONE lists for a standard condom. Sizes further down the chart run narrower, and those further up run roomier.

If even the widest sizes feel snug, Mister Size goes up to 69 mm, the largest width in the ranges covered here.

Mister Size condoms run 0.05 mm thick up to size 60, and 0.06 mm thick for its two biggest sizes, 64 and 69 (Mister Size). To put that in context, a standard condom sits at about 0.07 mm, as Condom Depot explains.

Mister Size pairs each of its widths with a range of erect girths (Mister Size):

For instance, 14 cm around points you to the 60 mm row.

You don't need to do any maths. Measure your girth, then find it in a brand's size chart, like the Mister Size one, and it will point you to the right width. To go backwards, ONE explains that doubling the nominal width gives you the condom's approximate circumference.