How do I know if my head is big or small?

September 27, 2025 •

4 min read

According to research, head size is highly determined by genetics, with some studies estimating a near 90% heritability rate in childhood. It's a question many wonder about: 'How do I know if my head is big or small?'

Quick Summary

Head size is primarily determined by genetics, with medical conditions affecting growth being rare. You can measure your head circumference for a general comparison, but ultimately, proportionality and overall health are more important. A doctor can track growth and address any concerns.

Key Points

Measurement is Key: Measure your head circumference with a flexible tape measure to get an objective number.
Genetic Factors: Your head size is largely determined by genetics, and significant variation is normal.
Consider Proportionality: Your perception of your head size is often influenced by your overall body proportions. Improving posture or muscle mass can affect this perception.
Monitor for Symptoms: If you notice rapid or unusual head growth (or lack thereof) along with other symptoms like headaches or developmental delays, seek medical advice.
Consult a Professional: A healthcare provider can track head growth using standardized charts and, if necessary, order tests to rule out underlying medical conditions.

Measuring Your Head Circumference

The most straightforward method for determining your head size is to measure its circumference. This can be done at home with a flexible measuring tape or even a string that you can then measure with a ruler. For the most accurate result, follow these steps:

Preparation: Use a soft, flexible measuring tape. If you don't have one, use a non-stretchy string or cord.
Position the Tape: Wrap the tape around the widest part of your head. This is typically about one to two finger widths above your eyebrows and ears.
Ensure Proper Placement: Make sure the tape is level and snug against your skin, but not too tight. It should follow the hairline at the back of your head.
Read the Measurement: Note the measurement in inches or centimeters where the tape overlaps. Take the measurement three times for consistency and use the largest number.

Comparing Your Measurement to Averages

After measuring, you can compare your result to general averages. Keep in mind that these are just averages, and a person's head size is highly individual and depends on numerous genetic factors.

Men: An average head circumference is often cited as being around 58 cm (22.8 inches).
Women: An average head circumference is often cited as being around 56 cm (22.0 inches).

If your measurement is significantly outside these ranges, it might be something to note, but it's not automatically a cause for alarm. For example, a head circumference greater than 22.5 inches is often considered large in hat sizing, while anything under 21.5 inches is petite.

The Role of Proportionality

Often, the perception of a head being 'big' or 'small' is more about its proportion to the rest of the body than its absolute size. For instance, a very skinny person may perceive their head as being too large for their frame. Conversely, a larger-bodied person might feel their head is too small in comparison. Developing your body's muscle mass can sometimes help create a more balanced and proportionate appearance. Proper posture can also influence how large or small your head appears relative to your body.

Medical Conditions and Head Size

While most variations in head size are benign and genetic, certain medical conditions can cause a person's head to be unusually large or small. It's important to consult with a healthcare professional if you have concerns, especially if other symptoms are present.

Macrocephaly (Larger-Than-Average Head)

Macrocephaly refers to a head circumference that is significantly larger than the average for a person's age and sex. This can sometimes be a benign familial trait, meaning it runs in the family and isn't a cause for concern. However, it can also be linked to more serious conditions like:

Hydrocephalus (fluid buildup in the brain).
Benign extra-axial fluid collections.
Certain tumors or bleeding.

Microcephaly (Smaller-Than-Average Head)

Microcephaly is a condition where a baby's head is much smaller than expected due to abnormal brain development. It can be caused by various factors, including genetic changes or exposure to certain infections during pregnancy.

How a Doctor Tracks Head Size

For infants and children, healthcare providers regularly track head circumference as part of routine checkups. This is a crucial screening tool for ensuring proper growth and development. They use specific growth charts to plot the child's measurements over time. For adults, head size is not routinely monitored unless there are specific concerns. A doctor might order imaging tests, like a head ultrasound or MRI, if they suspect an underlying medical cause.

Table: Head Circumference Comparison


Feature	Genetic Variation (Typical)	Medical Condition (Atypical)
Cause	Primarily determined by inherited genes.	Underlying health issues, such as hydrocephalus or microcephaly.
Growth Pattern	Steady and predictable growth that follows a genetic curve.	Unusual growth rate, either too slow (microcephaly) or too fast (macrocephaly).
Associated Symptoms	No associated symptoms; the individual is otherwise healthy.	Can be accompanied by other symptoms, such as developmental delays, headaches, or vision changes.
When to Seek Advice	Generally no need for concern unless other symptoms appear.	Always consult a healthcare provider if you notice unusual head size or related symptoms.

Conclusion: Focus on Health, Not Appearance

Ultimately, whether you perceive your head as 'big' or 'small' is often a matter of perception and overall body proportion rather than a health issue. Measuring your head can provide a general idea of where you stand relative to population averages, but genetic variation is vast and normal. The most important thing is to be mindful of your overall health. If you have concerns about your head size, or if you notice any associated symptoms, the best course of action is to speak with a healthcare provider who can evaluate your situation properly. For more information on human development and genetics, you can visit the National Institutes of Health website.

Frequently Asked Questions

While there is significant variation, the average adult male head circumference is around 58 cm, and for adult females, it is about 56 cm.

No, once the skull bones have fused after infancy, you cannot increase your head size. Any perception of a small head relative to your body might be related to overall body mass, which you can increase through exercise.

Benign familial macrocephaly is a large head size caused by genetics, with no associated symptoms. Pathological macrocephaly is due to an underlying medical condition, like hydrocephalus, and may be accompanied by other symptoms.

Yes, poor posture can make your head appear larger. For example, if you slouch and your head juts forward, it can appear closer and therefore bigger. Improving your posture can lead to a more balanced appearance.

You should consult a healthcare provider if you have any concerns, especially if you experience headaches, vision changes, or balance issues along with an unusually large or small head size.

There is no conclusive evidence to suggest a direct link between head size and intelligence. Genetic factors influence both, but the relationship is complex, and many other factors contribute to intelligence.

Hat size is a practical measure of head circumference. A larger hat size simply means a larger circumference and doesn't necessarily signify a medical issue. A hat size is a reference point for fitting, not a health diagnosis.