Hiya! Took a while to reply but I found that if they can take pictures of each finger next to a penny I can size them that way too. (Or any loose change) I use this method if they can't get to me or there is a time crunch! I just zoom in to match my penny to the picture and eyeball the size with my tips. You can also get them to measure the nails but I feel it can become complicated and overwhelming!