One a.m.u equals to

Atomic mass can be expressed as 1 a.m.u or one unified mass (U) or one Avogram (or) one Aston or Dalton. It is equal to $1.66\times {10}^{-24}g\left(or\right)1.66\times {10}^{-24}kg$

 Atomic mass unit (a.m.u): if we consider C-12 as the reference, then the quantity of mass equal to $\frac{1}{12}$ th of the mass of carbon-12 atom is known as a.m.u.  It is expressed in the following way.

            $\frac{1}{12}\times \frac{12\text{g}}{6.023\times {10}^{23}}=1.66\times {10}^{-24}\text{g}$    or  $1.66\times {10}^{-27}\text{kg}$

Therefore, one a.m.u equals to$1.66\times {10}^{-27}\text{kg}$ .