Shop Estare’s hair care picks, including her current shampoo, Aunt Jackie's. Read her interview here to find out about her hair care regime
Circumference: Measure all around the head. Position the tape mea sure so its edge follows the hairline around the head and nape of the neck.
Front to nape: Measure from your hairline at the centre of your forehead straight back over crown to centre of your hairline at the nape of your neck.
Ear to across forehead: At front of your ear, measure from your hairline at the base of your sideburn, up across the hairline along forehead to the same point in the front of the other ear.
Ear to over the top of head: Measure from your hairline directly above the ear across the top of your head to the hairline directly above the other ear
Temple to temple (round the back of head): Measure from temple to temple across the back of your head.
Nape of neck: Measure the width of your hairline across the nape of the neck.