Condom Size Calculator

How to measure girth for condom size

Your girth is the distance around your erect penis at its thickest point. A strip of paper and a ruler give you the number in about a minute.

Find your width

Erect
measure only when you are fully hard
Thickest
part of the shaft, usually just below the head
Half a cm
is close enough to pick a size (about a quarter inch)

Measuring your girth in four steps

  1. Cut the strip

    A strip of paper about 1 cm wide is ideal. String or a soft sewing tape also works.

  2. Wrap it around the thickest part

    When you are fully hard, wrap the strip once around the thickest part of the shaft. This is usually just below the head. Keep it snug, not tight.

  3. Mark the overlap

    Mark the point where the end of the strip overlaps itself, with a pen or your fingernail.

  4. Measure against a ruler

    Lay the strip flat along a ruler. The length from the end of the strip to your mark is your girth.

Getting a number you can rely on

Measure two or three times and use the middle number. The time of day doesn't matter, but you do need to be fully hard. If you are only half hard, the number comes out too small.

Write the number down in centimetres or inches and type it into the condom size calculator. It shows the width to buy, in millimetres, and the condoms made at that width.

Paper strip and ruler for measuring girth for condom size

Common mistakes

  • Measuring at the base instead of the thickest part.
  • Pulling the strip or tape too tight.
  • Measuring length. Fit depends on girth, not length.
  • Rounding up. Going from 4.6 to 5 inches can move you a whole size too big, so use the number you read.

A toilet roll test

Some people slide the cardboard tube from a toilet paper roll over the erect penis as a quick check. The condom brand ONE measured the inside of a typical tube at about 5 inches (12.7 cm) around, close to its own 55 mm condom.

If the tube feels loose, you are probably smaller than that. If it feels tight, you are probably bigger. That is all it can tell you, and tubes differ between brands, so ONE itself calls this a rough guide. A paper strip costs nothing and gives you your exact number.

How to know your condom size from the fit you have now

If a condom pinches, leaves a red ring or rolls back up, it is too small. If it wrinkles, bunches up or slips, it is too big. Measuring tells you your real size, and our pages on a condom that is too tight and a condom that slips off explain what to try next.

Measuring questions

Do I measure length or girth for a condom's size?

Girth, the distance around. The width of a condom depends on girth, and almost every condom is long enough.

My measurement falls between two sizes. Now what?

If you are near the bottom of a size range, try the narrower width first. If you are near the top, try the wider one. Trial packs with three widths let you test this without spending much.

How do I know which condom size to buy?

Measure your girth first, then buy the width the calculator gives you. Words on the box such as regular, large or XL mean different widths at different brands, so go by the number in mm.

How can I tell what your condom size is from the fit?

Too small: it pinches, rolls up or breaks. Too big: it wrinkles or slips off. The right size rolls all the way down and stays in place without leaving a red ring.

How do I choose a condom size across different brands?

Compare the width in mm, not the name on the box. The condom size chart lists the width of every product.

What size condom should I use or buy if I have never measured?

Start with a regular condom, about 53 to 54 mm wide. If it feels tight or loose, use the signs above to move up or down a size. Measuring with a strip of paper gives you the real answer in a minute.

Can I get nominal width from girth on my own?

You can, roughly, but you don't need to. The condom brand Okamoto suggests dividing your girth by 3.14 (pi). Our calculator uses a size table from the brand Mister Size instead, which gives a slightly tighter width that stays on better. Just type your number into the calculator.

Where to go from here

Condom size calculatorType your girth, get your width in mmCondom size chartEvery brand's widths side by sideWhat nominal width meansAnd how girth turns into it

Sources