I know that $|a+bi|=\sqrt{a^2+b^2}$ for any complex numbers $a$ and $b$. So, I can apply this formula to $-1+i\sqrt3$. I get $|{-1+i\sqrt3}|=\sqrt{(-1)^2+(\sqrt3)^2}$. This simplifies to $\sqrt{1+3}=\sqrt4=2$. 
Evaluate $|{-1+i\sqrt3}|$.