A computer-implemented method for estimating characteristics (Qn', QI') of a liquefied natural gas load carried or intended to be transported by a transport ship, wherein the characteristics include a liquefied natural gas composition and a quantity of liquefied natural gas, characterized in that the method comprises: the extraction, using statistical correlation, from an experience database of a law linking the instantaneous transformation of the composition and quantity of liquefied natural gas to instantaneous navigational conditions, to characteristics of the LNG tanker and to the nature of the liquefied natural gas initially on board, the instantaneous transformation of the composition and of the quantity of liquefied natural gas being due to evaporation and formation of evaporated gas, wherein the instantaneous navigational conditions comprise the state of the sea, the ship speed and the atmospheric state, the experience database being formed during a phase using a fleet of ships, or a single ship, each ship being equipped with different sensors and recorders to measure the quantity and the nature of the different components of the evaporated gas along the trip of the ship, and selecting a plurality of intended trips (410, 411, 412) for the transport ship, integrating, over each envisaged trip (410, 411, 412, 420; 510, 511, 512) from a reference point (400, P; 500) at which said characteristics are known (Qn, Qi) and to an estimation point of the envisaged trip, the law relating the instantaneous transformation of the composition and of the quantity of the liquefied natural gas to the instantaneous navigation conditions, the integration being performed according to the anticipated or predicted navigation conditions along the envisaged trip from the reference point to the estimation point, in order to obtain an estimation of the composition and of the quantity of liquefied natural gas at the estimation point of the envisaged trip, selecting a trip that provides an optimal estimated composition and/or a larger estimated quantity of liquefied natural gas from among said intended trips. the extraction, using statistical correlation, from an experience database of a law linking the instantaneous transformation of the composition and quantity of liquefied natural gas to instantaneous navigational conditions, to characteristics of the LNG tanker and to the nature of the liquefied natural gas initially on board, the instantaneous transformation of the composition and of the quantity of liquefied natural gas being due to evaporation and formation of evaporated gas, wherein the instantaneous navigational conditions comprise the state of the sea, the ship speed and the atmospheric state, the experience database being formed during a phase using a fleet of ships, or a single ship, each ship being equipped with different sensors and recorders to measure the quantity and the nature of the different components of the evaporated gas along the trip of the ship, and selecting a plurality of intended trips (410, 411, 412) for the transport ship, integrating, over each envisaged trip (410, 411, 412, 420; 510, 511, 512) from a reference point (400, P; 500) at which said characteristics are known (Qn, Qi) and to an estimation point of the envisaged trip, the law relating the instantaneous transformation of the composition and of the quantity of the liquefied natural gas to the instantaneous navigation conditions, the integration being performed according to the anticipated or predicted navigation conditions along the envisaged trip from the reference point to the estimation point, in order to obtain an estimation of the composition and of the quantity of liquefied natural gas at the estimation point of the envisaged trip, selecting a trip that provides an optimal estimated composition and/or a larger estimated quantity of liquefied natural gas from among said intended trips.