Carat weight refers to size and weight of the diamond. Larger diamonds are more scarce than smaller diamonds, and therefore, more valuable. However, two diamonds with the same carat weight, can vary greatly in price depending on the color, clarity and most importantly, cut.
A smaller diamond with excellent color and clarity may cost more than a larger diamond with lower color and clarity.
It is simply a matter of deciding what matters most to you, size or quality. It is wise to find the best combination of size, color and clarity to suit your budget.