I really wish TNF gives clear measurements for toddler products! I could not find anything on the Internet that showed how big or small these mittens were and these are not just one "toddler" size but separate 2T, 3T and 4T sizes! I took a chance by ordering size 3T for my 3 year old (3 years and 2 months) who I think has average sized hands/fingers (not scientific since I've never compared his hands with any other toddlers!). My son's hand is 4-1/2" from the center wrist straight to the tip of his middle finger. His thumb is 1-1/4" long and the widest part of the palm is 2-1/2" wide (fingers together, measured at the "foot" of the thumb where it sticks out a little). The mittens, on the other hand, are 5" from the wrist line to the tip, 2" long thumb, and about 3" to 3-1/4" width. The mittens have elasticized wrists (in addition to the velcroed 'flap' on the back side of the hand that can be used to adjust the widths) and about 3" long extra material that extends towards the arms, finished with some more elasticized cuffs. If you look at the mittens, the bottom half is as big as the top (the hand) part of it so these are super long mittens! The inside of the mittens are lined with fleece. I got the black ones which seem to have a different type of the adjustable flaps than the pink or blue (see the pictures closely).
Now, obviously the mittens are quite bigger than my son's hands but with the elastics and adjustability plus the extra length, the fit is not bad at all. His thumbs are not lost in them and he can easily grab things while wearing the mittens. He cannot shake the mittens off when he is wearing them either. There's enough room so I'm pretty sure we can get 2 years (winters) of use out of them which is a great plus! I also really love how long the mittens are - it'll ensure snow won't creep in when he's busy playing (they'll be tucked inside the sleeves of his jacket). After all, we've had too many mittens that don't stay on and/or uncomfortable! We have not had snow yet here so I cannot tell you how "waterproof" these are (they do say these are waterproof.) but I'm hoping these will be the best toddler snow mittens ever for us!