LANGUOR sleep masks are usually made just as you order them.  I sew my masks to a standard size based on the patterns I created, as described below.  If you need more of a custom size you can let me know and I will tell you if I can do it.  Changes such as adding a little extra elastic or making the mask a little taller or narrower are adjustments that are fairly easy for me to do and won't have an extra charge.

For eyemasks with plain (non-adjustable) elastic straps -

• Large adult: Mask is about 8 x 3 inches (20 x 7.5 cm) from center. Elastic is about 13.5 inches (34 cm). Fits a head about 22.5-24 inches (57-61 cm).
• Average adult/teen: Mask is about 8 x 3 inches (20 x 7.5 cm) from center. Elastic is about 12.5 inches (32 cm). Fits a head about 21-23 inches (53-58 cm).
• Child 6-11 years: Mask is about 7.5 x 2.5 inches (19 x 6.5 cm) from center. Elastic is about 12 inches (30.5 cm). Fits a head about 20-21.5 inches (51-54.5 cm). This mask shape is the exact same as my “ Small adult ” size mask. Adults who need a smaller mask or prefer less coverage on their faces find that with the adjustable strap option this size is right for them.
• Child 3-5 years: Mask is about 7 x 2 inches (18 x 5 cm) from center. Elastic is about 11.5 inches (29 cm). Fits a head about 19-20 inches (48-51 cm).  Some adults even like this size either with an adjustable strap or by asking me to add a couple inches extra to the elastic.

For eyemasks with adjustable elastic straps -

• Adult: Mask is about 8 x 3 inches (20 x 7.5 cm) measured from the center. Generously sized, this mask fits most adults and teens well.
• Child 6-11 years/Small Adult: Mask is about 7.5 x 2.5 inches (19 x 6 cm) from center. Designed to fit kids 6-11 years old. Adults who need a smaller size or prefer less coverage find this size fits them well.
• Child 3-5 years: Mask is about 7 x 2.25 inches (17.5 x 5.5 cm) from center. Designed to fit most kids 3-5 years old.

The adjustable strap is about 16 inches long, unstretched and fully extended, making the adult size mask approximately 24 inches around unstretched.  Extra large heads who are afraid of a snug mask might want it an inch or two longer, simply include a note at checkout.

(The three sizes are shown above, from the top down: child 3-5 years, child 6-11 years, adult. Note that the average adult/teen size is the same size mask as the large adult, the difference is the length of elastic.)

Size Fit Tips

• If in doubt - size up. Unless you hate the idea of a mask that covers your face too much, then size down, but be sure the strap will fit or get the adjustable strap.
• Your 4 or 5-year-old probably WILL want the child 6-11 years size, if not today, then likely soon. 
• Measure.  Use Dental floss, a shoe lace, ribbon, etc to go around your head over the eyes and then lay that next to a ruler.

Over-sized Sleep Masks

I do make an over-sized sleep mask.  This mask is about 1 inch wider and taller all the way around compare to my average adult mask.  The elastic strap is still sized based on the entire circumference of the head, though I do have a slighter wider elastic to use if requested.  I charge $3 extra for the over-sized mask and you have to ask for it before ordering so that I can be sure I have enough of the front fabric and then to add that size option for you to place your order. 

Extra long sleep masks

Here in Wisconsin it gets cold, quite cold.  Several winters ago I experimented with making a sleep mask that goes all the way past each ear, to cover the ears so they stay warm at night.  I found that while the mask worked and was comfortable, it wasn't really necessary, (I prefer to sleep with my head under blankets with only my face, peeking out and a normal eyemask is just nice enough.)  It was also tricky to size the elastic because the elastic at the back was so short from the mask being so wide and hence, the elastic didn't stretch much, nor hug the face well.  I then spaced two pieces of elastic on the back of the mask instead of just one.  This worked better, but felt a little claustrophobic for me though the mask was not tight and the mask had a tendency to slip around.  Therefore, I don't offer this style of mask currently, but am open to your thoughts if you are interested.