Quick answer

To find your condom size, measure erect girth with a flexible tape or string at the widest point, then measure erect length from base to tip. Compare those numbers to a fit chart, like MyONE's Girth Number and Length Letter system, and choose the size that matches both. Remeasure twice for consistency and avoid guessing from memory.

Why measuring before you buy saves time and money

A condom that is too tight can be uncomfortable and may be more likely to break, while one that is too loose can slip off. Measuring at home helps you avoid both problems. MyONE uses a two-part sizing system: a Girth Number (nominal width in millimeters) and a Length Letter (length in inches). For example, Size 64L has a 64mm nominal width and an 8.5-inch length, while Size 55G has a 55mm nominal width and a 6.5-inch length. Knowing both numbers lets you pick a condom that fits your girth and length, not just one or the other.

What you need to measure at home

You do not need special tools. A flexible measuring tape (the kind used for sewing) works best. If you do not have one, use a piece of string or a strip of paper and then measure it against a ruler. Measure when you are fully erect, ideally at room temperature, because cold can affect size. Take each measurement twice to check for consistency. Write down both numbers so you can compare them to the MyONE sizing chart.

How to measure girth correctly

Girth is the most important measurement for condom fit because it determines whether the condom stays put without being too tight. Wrap the tape or string around the widest part of your erect penis, usually near the middle or base. Keep it snug but not compressing the skin. Read the circumference in millimeters or inches. If you use string, mark where it overlaps, then lay it flat against a ruler. MyONE's Girth Numbers range from 45 to 64, and each number corresponds to a nominal width in millimeters. For instance, a girth of about 64mm matches Size 64L, while a girth of about 55mm matches Size 55G. Always round to the nearest available size if you are between numbers.

How to measure length correctly

Length matters for comfort and coverage, but it is less critical than girth for staying secure. Measure from the base of the penis (where it meets the body) to the tip, pressing the ruler gently against the pubic bone. Do not add extra length or pull the tape tight. MyONE Length Letters range from A to L, with each letter representing a length in inches. Size 64L has an 8.5-inch length, Size 57K has an 8-inch length, and Size 55G has a 6.5-inch length. If your length falls between two letters, choose the shorter letter if you prefer a snugger fit, or the longer letter if you want more coverage. Remember that condoms are designed to accommodate some variation, so exact length is less critical than girth.

Common measuring mistakes to avoid

One frequent mistake is measuring while flaccid. Condom size should be based on erect measurements because that is when you will use it. Another error is pulling the tape too tight around the girth, which gives a smaller number and leads to a too-tight condom. Also, do not measure length by starting at the tip and going down; always start at the base. Finally, do not rely on a single measurement. Take at least two measurements on different days to account for natural variation. If your measurements are inconsistent, average them and then round to the nearest MyONE size.

Using the MyONE sizing chart

Once you have your girth and length, use the MyONE sizing chart to find your FitCode. The chart combines a Girth Number (45–64) and a Length Letter (A–L). For example, if your girth is 57mm and your length is 8 inches, your FitCode is 57K. If your girth is 64mm and your length is 8.5 inches, your FitCode is 64L. MyONE offers a range of sizes to cover most combinations. If you are between two girth numbers, choose the larger number if you find regular condoms too tight, or the smaller number if they feel loose. The goal is a snug fit that does not roll down or pinch.

Your condom fit checklist: 5 steps to the right size

  1. Gather your measuring tools: Use a flexible measuring tape or a piece of string and a ruler. Make sure you have a pen and paper to record numbers. Checkpoint: Do not use a rigid ruler for girth; it will not wrap accurately.
  2. Measure girth at the widest point: Wrap the tape around the widest part of your erect penis. Keep it snug but not tight. Record the circumference in millimeters. Common mistake: Pulling too tight gives a smaller number and a too-tight condom.
  3. Measure length from base to tip: Place the ruler at the base, press gently against the pubic bone, and measure to the tip. Record the length in inches. Common mistake: Starting at the tip and measuring downward, which adds extra length.
  4. Repeat both measurements: Take each measurement at least twice, ideally on different days, to account for natural variation. Average the numbers if they differ. Checkpoint: If your measurements vary by more than a few millimeters, remeasure carefully.
  5. Match to MyONE FitCode: Use your girth and length to find your Girth Number and Length Letter on the MyONE sizing chart. For example, 57mm girth and 8-inch length = 57K. Next step: If you are between sizes, choose the larger girth number for a looser feel or the smaller for a snugger fit.

MyONE sizes that match common measurements

  • MyONE® Size 64L My Custom Fit® Condom: MyONE® Super-Wide Condom 64L combines our widest Girth Number 64 (64mm nominal width) with Length Letter L (8.5 inches). If your girth measures around 64mm and your length is about 8.5 inches, this size gives you the widest fit MyONE offers.
  • MyONE® Size 55G My Custom Fit® Condom: MyONE® Classic Wide Condom 55G is sized for those who need a little more girth and a bit less length. FitCode 55G combines Girth Number 55 (55mm nominal width) with the G Length Letter (6.5 inches). A good match if your girth is around 55mm and your length is about 6.5 inches, providing extra width without excess length.
  • MyONE® Size 57K My Custom Fit® Condom: MyONE® Extra-Wide Condom 57K is sized for those who need a slightly longer and wider fit. FitCode 57K combines Girth Number 57 (57mm nominal width) with Length Letter E (8 inches). Choose this if your girth is about 57mm and your length is around 8 inches, offering a balance of width and length.