Condom Size Calculator – Girth to Nominal Width (Inches & CM)
Use our free condom size calculator to calculate condom size from your girth in inches or cm. This girth to nominal width calculator (and circumference to nominal width) gives you the right nominal width and fit category, plus a sizing chart and brand list. Works as a condom fit calculator and condom sizing calculator—no sign-up.
Last updated: February 2, 2026
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Measure from base to tip when fully erect
Measure around the thickest part when fully erect
Tip: Girth is the most important measurement for proper condom fit. Use a flexible measuring tape or string.
Your Condom Size
Recommended Size
Regular/Standard Fit
Nominal Width
57mm
Look for this on condom packaging
Fit Analysis:
You can use standard/regular fit condoms available at most stores
Key Recommendations:
- •Most widely available condom size
- •Nominal width: 50-54mm
- •Fits approximately 70% of men
- •Easy to find in stores and pharmacies
Popular Brands to Try:
- ✓Trojan ENZ (53mm)
- ✓Durex Extra Sensitive (52mm)
- ✓LifeStyles SKYN (53mm)
- ✓Kimono MicroThin (52mm)
Important Safety Notes:
- • Wrong size increases risk of breakage or slipping
- • Check expiration dates before use
- • Use water-based or silicone-based lubricants only
- • Never reuse condoms
- • Store in cool, dry place away from direct sunlight
Condom Size Chart & Nominal Width Guide
Girth Range
Under 4.7"
(<120mm)
Nominal Width
45-49mm
Prevents slipping and ensures proper fit for smaller sizes
Girth Range
4.7" - 5.1"
(120-130mm)
Nominal Width
50-54mm
Widely available at all retailers and pharmacies
Girth Range
5.1" - 5.5"
(130-140mm)
Nominal Width
54-58mm
Includes Magnum and other large size brands
Girth Range
Over 5.5"
(>140mm)
Nominal Width
58mm+
May require custom sizing or specialty brands
Girth to Nominal Width Calculator – Circumference to Nominal Width
This tool works as a girth to nominal width calculator and circumference to nominal width converter: enter your girth (circumference) in inches or cm above and get your nominal width in mm plus your fit category. The formula is nominal width (mm) = girth (mm) ÷ 2. You can also work backwards: nominal width to girth is girth = nominal width × 2 (e.g. 52 mm → 104 mm girth).
Example: Calculate Condom Size from Girth (Inches & CM)
For girth of 4.5 inches (114 mm): nominal width = 114 ÷ 2 = 57 mm. Use the calculator above for your own girth in inches or cm.
Recommended Size
Regular / Large
Nominal Width
57 mm
How Our Condom Size Calculator Works
Our condom size calculator works as a girth to nominal width calculator and circumference to nominal width tool: you enter your girth in inches or cm and we give you your nominal width in mm. The formula is nominal width = girth (mm) ÷ 2. That nominal width is the key spec for condom fit and the main factor for safety and comfort.
Condom Size Calculation Formula
Nominal Width (mm) = Girth (mm) ÷ 2This formula calculates the flat width of the condom that will provide optimal stretch and fit. Condoms are designed to stretch to approximately double their nominal width, creating the proper snug fit around your girth. The right nominal width ensures the condom won't slip off (too loose) or break (too tight).
Example Calculation:
Given: Girth = 4.5 inches (114mm)
Calculation: 114mm ÷ 2 = 57mm nominal width
Result: Regular/Standard Fit (50-54mm range)
Recommendation: Trojan ENZ, Durex Extra Sensitive, LifeStyles SKYN
How to Measure for Condom Size
Accurate measurement is essential for finding the right condom size. Follow these steps for proper measurement:
- Measure when fully erect: Measurements must be taken during full erection for accuracy
- Use a flexible measuring tape: A fabric tape or piece of string works best
- Measure girth around the thickest part: Wrap tape around circumference at widest point
- Measure length from base to tip: Press ruler against pubic bone for accurate length
- Girth is more important than length: Focus primarily on circumference measurement
- Measure multiple times: Take 2-3 measurements and use the average for accuracy
Why Proper Condom Fit Matters
Using the correct condom size is crucial for both safety and comfort. A properly fitted condom provides the best protection against pregnancy and STIs while maintaining comfort and sensitivity during intimacy.
Risks of Improper Fit:
- Too Tight: Increased risk of breakage, discomfort, restricted blood flow, reduced sensation
- Too Loose: Increased risk of slipping off, reduced effectiveness, leakage, decreased protection
Sources & References
- World Health Organization (WHO) - Condom Technical SpecificationsInternational standards for condom sizing and testing
- Centers for Disease Control and Prevention (CDC) - Condom Effectiveness and Proper UseEvidence-based guidance on condom selection and usage
- Planned Parenthood - Sexual Health ResourcesComprehensive information on safe sex practices
Explore more lifestyle tools with our productivity calculator and nutrition calculator.
Get Custom Health CalculatorPopular Condom Brands by Size
Snug/Slim Fit (45-49mm)
Regular/Standard Fit (50-54mm)
Large Fit (54-58mm)
Extra Large Fit (58mm+)
Frequently Asked Questions
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