Make this lovely felt birthday crown with a free pattern and tutorial. Easy to follow tutorial, hand sewing possible. For the birthday crown size, you'll need to measure around your child's head where the felt crown will sit. The child of my friend (3 years old) measured 52 cm (20.5 inches). The finished DIY birthday crown should be approximately 2 cm (3/4 inch) smaller than the head measurement. If the elastic is stiffer, then 1,5 cm (1/2 inch) will be enough.