The bigger the carat, the heavier the stone, which of course also means that the stone will be larger.
The tables and pictures below will show you how - for each diamond shape - the measurements of a diamond vary with its carat weight.
Note: The tables below serve as indication only. The exact measurements of a diamond can be found in its GIA certificate, which you should always open and carefully read before buying one. Learn how to read a GIA certificate.