Find your perfect fit using a sizing kit. Match natural nail to press-on by looking for best fit; ensure none of the natural nail us exposed at the sides (=nail is too small) & press-on isn't overlapping with cuticle (=nail is too big).
Different shaped tips may fit slightly different, choose the trio to try them all.
For all coffin lengths (minus short) choose the coffin sizing kit
For all ballerina, almond, and stilleto lengths, choose the ballerina sizing kit
For all square lengths, choose the square sizing kit
For short round and short coffin shape, choose short coffin sizing kit