Hat Size Calculator

Calculate your hat size based on your head circumference in inches or centimeters

Input Parameters

cm

Calculation Results

Hat Size

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Calculation Formula

Hat Size (US) = ((Head Circumference in cm - 40) / 2.54) + 7

Where:
- Head Circumference in cm is your measured head size in centimeters
- The formula converts centimeters to inches (1 inch = 2.54 cm) and then calculates the hat size

Hat Size Calculator Usage Guide

Learn how to use the Hat Size Calculator and understand its working principles

How to Use This Calculator

  1. Enter your head circumference measurement in either centimeters or inches
  2. Click the "Calculate" button to determine your hat size
  3. Your US hat size will be displayed in inches
  4. You can switch between metric (cm) and imperial (in) units using the dropdown

How the Calculation Works

This calculator uses the standard hat sizing formula where your head circumference is converted from centimeters to inches (1 inch = 2.54 cm), then adjusted using the formula: Hat Size (US) = ((Head Circumference in cm - 40) / 2.54) + 7

For example, if your head circumference is 60 cm:
(60 - 40) / 2.54 + 7 = 20 / 2.54 + 7 = 7.87 + 7 = 14.87 inches, which rounds to 14.9 inches (US size 7)

Important Notes

  • This calculator provides an approximate hat size based on head circumference
  • Different countries may use different sizing systems (e.g., European sizes)
  • For best results, measure your head circumference while wearing a tight-fitting hat
  • Remember that some hat styles may require adjustment for comfort