Head Girth Calculator

How to Use the Head Girth Calculator

Follow these simple steps to measure your head circumference and find your correct hat and helmet sizes:

1. Measure Your Head: Use a flexible measuring tape positioned about 2.5 cm (1 inch) above your eyebrows and ears, around the widest part of the back of your head. Keep the tape level and snug but not tight.
2. Select Your Unit: Use the toggle switch to choose between metric (centimeters) or imperial (inches) measurement.
3. Enter Your Measurement: Type your head circumference into the input field, or use the quick preset buttons for common sizes.
4. View Your Results: The calculator instantly displays your measurement in both units, plus recommended hat and helmet sizes for various sports.

What is Head Girth?

Head girth, also known as head circumference, is a measurement of the distance around the head at the level immediately above the eyebrows and ears. This anthropometric measurement is essential for properly fitting athletic equipment including helmets, hats, caps, and protective headgear across numerous sports.

For athletes, head circumference measurements serve several important purposes:

• Safety Equipment Sizing: Properly fitted helmets provide optimal protection in cycling, football, baseball, hockey, and motorsports
• Performance Gear: Swimming caps, wrestling headgear, and boxing headgear require accurate sizing for comfort and function
• Anthropometric Assessment: Head girth is one component of comprehensive body composition and body size testing protocols
• Equipment Procurement: Coaches and teams need size data when ordering uniforms and protective equipment

Average Head Circumference by Gender

According to research published in medical literature, adult head circumference varies by gender and is related to overall body height. Understanding these averages helps athletes and coaches determine where an individual falls on the size spectrum:

Head circumference is strongly correlated with height, meaning taller individuals typically have larger head measurements. Research by Bushby et al. (1992) demonstrated that adult head circumference relates to height, with males averaging approximately 1.3 cm larger than females.

Head Girth Measurement Procedure

The head circumference measurement is taken at the level immediately above the brow. This standardized technique ensures consistent, comparable measurements across different testing sessions and between individuals.

Purpose: To measure the circumference of the head as one of the many measurements of body size, and to determine proper sizing for athletic equipment.

Equipment Required: A flexible metal tape measure and pen suitable for marking the skin if needed. If a plastic or cloth tape is used, it should be checked regularly against a metal tape as these may stretch over time.

Pre-test Procedures: Explain the test procedures to the subject. Prepare forms and record basic information such as age, height, body weight, and gender. See more details of pre-test procedures.

Procedure: The subject may stand or sit for this measurement. When recording, ensure the tape compresses the hair and is kept horizontal. Remove any ties, clips, or accessories from the hair, and ensure the ears are not included in the measurement.

Reliability: Factors that may affect reliability include changes to the testing personnel, maintaining constant and even tension on the tape, and correct landmarking (finding the correct anatomical site for measurement).

Advantages: Low costs involved in the testing procedure, ease of self-testing, and immediate applicability for equipment sizing.

Comments: Girth measurements combined with skinfold measurements can give a clearer picture of changes in tissue composition and distribution of muscle and fat.

Sport-Specific Helmet Sizing

Different sports use varying helmet sizing systems. Understanding these standards helps athletes select properly fitting protective equipment:

Cycling Helmets

Cycling helmet sizes typically follow this standard:

• Small: 51-55 cm (20-21.7 inches)
• Medium: 55-59 cm (21.7-23.2 inches)
• Large: 59-63 cm (23.2-24.8 inches)

Most cycling helmets feature adjustable retention systems for fine-tuning fit within each size range.

Football Helmets

Football helmets require precise fitting due to the high-impact nature of the sport. Professional fitting by certified equipment managers is recommended, with sizes typically ranging from youth to adult XXL.

Baseball/Softball Helmets

Batting helmets commonly use these size designations:

• Small: 6 3/8 - 6 7/8 (51-55 cm)
• Medium: 6 7/8 - 7 1/4 (55-58.4 cm)
• Large: 7 1/4 - 7 5/8 (58.4-61.4 cm)

Hockey Helmets

Ice hockey and field hockey helmets are sized similarly to cycling helmets, with additional considerations for face cage or visor attachment.

Hat Size Conversion Chart

Understanding the relationship between head circumference and hat sizes helps when purchasing fitted caps, beanies, and athletic headwear:

Tips for Accurate Head Measurement

To ensure the most accurate head circumference measurement for athletic equipment fitting:

• Use the Right Tool: A flexible fabric or plastic measuring tape provides the most accurate results. Metal tapes are acceptable but less conforming.
• Consistent Positioning: Always measure at the same anatomical landmarks - above the eyebrows and ears at the widest point of the skull.
• Hair Considerations: Compress hair when measuring, or measure with the hairstyle you'll wear during activity (for swimming caps, measure with wet hair).
• Multiple Measurements: Take at least three measurements and use the largest value.
• Between Sizes: When falling between sizes, generally choose the larger size. Most helmets have adjustment systems to fine-tune fit.