We present densities of pure 1-butanol and isobutyl alcohol from (283.15 to 363.15) K at pressures up to 66 MPa. We have measured densities using a vibrating tube densimeter. We use a forced path calibration method since this method depends mainly upon the mechanical properties of the cell. Experimental measurements of n-heptane have been measured to test the reliability of the apparatus. These measurements agree with a reference equation of state within 0.1 %. The new experimental densities of 1-butanol and isobutyl alcohol agree within 0.2 % with densities from the literature.