Procedure for measuring a level of a product in a vessel, said level varying over time, with a level transmitter that works according to the time of flight principle, wherein - transmission signals are sent periodically in the direction of the product, - their echo signals are recorded and converted into an echo function (A(t)) that reflects their amplitudes depending on their time of flight (t), - successive measurements are carried out wherein at least one echo property of the echo function (A(t)) is determined during each measurement, specifically a time of flight (t L, t S, t B) of a maximum (L, S, B) of the echo function (A(t)) which is attributable to a reflection at a known reflector, wherein the known reflectors comprise a product surface and/or a floor of the vessel, in that -- on the basis of the echo properties determined in the last two previous measurements, it is possible to make a forecast for the echo property to be expected in the current measurement by calculating a current change in the velocity v(T L), v(T S), v(T B) of the times of flight and extrapolating the expected time of flight (T L, T S, T B) on the basis of this velocity v(T L), v(T S), v(T B), -- the echo properties of the current measurement are determined taking the forecasts into account, and -- the current level is determined on the basis of the echo properties of the current measurement. - transmission signals are sent periodically in the direction of the product, - their echo signals are recorded and converted into an echo function (A(t)) that reflects their amplitudes depending on their time of flight (t), - successive measurements are carried out wherein at least one echo property of the echo function (A(t)) is determined during each measurement, specifically a time of flight (t L, t S, t B) of a maximum (L, S, B) of the echo function (A(t)) which is attributable to a reflection at a known reflector, wherein the known reflectors comprise a product surface and/or a floor of the vessel, in that -- on the basis of the echo properties determined in the last two previous measurements, it is possible to make a forecast for the echo property to be expected in the current measurement by calculating a current change in the velocity v(T L), v(T S), v(T B) of the times of flight and extrapolating the expected time of flight (T L, T S, T B) on the basis of this velocity v(T L), v(T S), v(T B), -- the echo properties of the current measurement are determined taking the forecasts into account, and -- the current level is determined on the basis of the echo properties of the current measurement. -- on the basis of the echo properties determined in the last two previous measurements, it is possible to make a forecast for the echo property to be expected in the current measurement by calculating a current change in the velocity v(T L), v(T S), v(T B) of the times of flight and extrapolating the expected time of flight (T L, T S, T B) on the basis of this velocity v(T L), v(T S), v(T B), -- the echo properties of the current measurement are determined taking the forecasts into account, and -- the current level is determined on the basis of the echo properties of the current measurement.