How do you pick the right size? A thimble should stay comfortably on your finger. Hang your hand at your side. If the thimble does not fall off, it is a good fit. It also should not be too tight and squeeze your fingertip. It is possible you may need 2 different sizes of thimbles depending on the season. Fingers may swell a little in different temperatures and while sewing. (Like many Dritz® thimbles, the soft comfort thimble shown is available in three sizes: small, medium and large.)