We measured the Doppler lineshifts in the spectra of the Sun and stars with effective temperatures from 4800 to 6200 K and estimated the average convective (granulation) velocities. The absolute scale of the lineshifts for stars was established on the basis of the derived dependence of the shifts of solar lines on optical depth. For FGK solar-type stars we first got curves convection velocities as a function of the height in the atmosphere in a large range of heights from 150 to 700 km. These curves are similar to each other. They indicate a decrease in blue shifts with height, which means that the granulation velocities through the photosphere slow down to zero. In the lower chromosphere, red shifts of strong Mg I lines are observed, which indicate a change in the direction of granulation velocities to the opposite and confirm the effects of reversal of granulation at heights above 600 km. In cooler K stars, granulation shifts change with height on average from –150 to 100 m/s, while in hotter FG stars they change more sharply from –700 to 300 m/s. The gradient of the curves of lineshifts increases with an increase in the effective temperature, with a decrease in gravity, metallicity, and age of the star. The convective velocity of the star averaged over all analyzed heights increases from –90 to –560 m/s from colder to hotter stars. It correlates with macroturbulence, asymmetry of spectral lines, and the velocity of rotation of the star. We also obtained the radial velocities of the studied stars and compared them with the SIMBAD data. Large deviations of –21050 and 1775 m/s were found for the stars HD 102361 and HD 42936, respectively. For the rest of the stars, the deviation does not exceed ±340 m/s, which is probably associated with the use of an average granulation velocity of –300 m/s in the SIMBAD data. Our analysis has shown that the average granulation velocity is not the same for solar-type stars. It is lower (higher) in colder (hotter) stars than the Sun. Therefore, in determining the radial velocities, it is necessary to take into account the individual granulation velocities of stars.