This link will take you to a helpful video demonstrating how to measure for a Bedhead Hats hat:
Steps to success!
Step 1: Distract the child with a toy or food (so they don't try to help you!).
Step 2: Use a measuring tape to take the measurement. Otherwise, use a ribbon to take the size then use a ruler to find the measurement.
Step 3: Choose a hat size closest to your child's measurement. These fabrics are very stretchy and will grow up to 4cms. For example: the child's head measures 41cms, you will need the 42cm size that will stretch another 4cms up to 46cms - giving plenty of future wear. Purchasing the next size up would be too large and block the child's vision.
TIP: It's best for babies to learn to wear hats from birth, before motor skills develop.