Winter and ski gloves use the hand circumference scale too: Hestra’s chart runs 5 at 127 mm, 6 at 152 mm, 7 at 178 mm, 8 at 203 mm, 9 at 229 mm, 10 at 254 mm, 11 at 279 mm, 12 at 309 mm, 13 at 330 mm, and sells its mitts on the same numbers. A liner adds its thickness all the way round the hand, so the shell has to fit a perimeter 2π × thickness longer: about 6 mm for a 1 mm liner.
Glove, mitten or 3-finger
Mittens keep the fingers together and are warmer for the same insulation; 3-finger (lobster) mitts keep a trigger finger free. All take the size of the hand: a mitten in your glove size, not a size up.
An 8" hand with a 1 mm liner measures 209 mm: Hestra 8. With a 2 mm liner it is 216 mm, Hestra 8.
shell circumference = hand + 2π × liner thickness 1 mm ≈ +6 mm ≈ a quarter size
Kids
Reusch’s kids chart runs size 3.5 for ages 5–6, 4 for 6–7, 5 for 8–9, 6 for 10–12 and 7 for 14–16, with Roman-numeral mitts for toddlers. Measure when you can; children’s hands vary as much as their heights.
Brand cuts differ inside a size: when the sizer lands between two sizes, or on the edge of a band, try both.
Liners, warmth and dexterity
A liner traps a layer of still air inside the shell, which is most of what keeps a hand warm. A thin merino or polyester liner is about 1 mm, adding 6 mm round; a fleece liner nearer 2 mm, adding 13 mm. Size the shell over the liner you will wear, or the insulation is compressed and the gloves are colder than their rating.
Children’s hands fall between the adult numbers: a 6" hand is Hestra 6, a 6.5" hand 7 (rounded to the chart), and Reusch’s kids’ scale continues below in half sizes by age.
Why the screen can be trusted
A browser does not know how big its pixels are, so the sizer starts from a table of 114 phones, tablets, laptops and monitors matched to your screen’s size and pixel ratio, an estimate good to about five percent. Laying a coin or a bank card on the glass and matching its outline replaces the estimate with a measurement good to a fraction of a percent, saved for this screen only.
Browser zoom is corrected automatically from the pixel ratio; pinch zoom is flagged, because nothing drawn is true size until it is undone.
pixels per mm = CSS px across the card ÷ 85.60 mm ID-1 card: 85.60 × 53.98 mm (ISO/IEC 7810)