The final spread of a liquid droplet on a flat solid surface was experimentally studied at room temperature. Five mixtures of water and glycerol and three different substrates (silicon wafer, aluminum, and wax) were used to study the final spread under influences of liquid viscosity and substrate wettability. It was found that the spreading meniscus of water droplets in the final equilibrium state corresponds to the static contact angles of the substrates. However, we observed that the glycerol droplets of high viscosity have almost the same contact angles on all three substrates. In addition, a quantitative analysis shows that, for a given impacting velocity, the normalized final spread decreases inversely with an increase in the Ohnesorge number, and the correlation between the normalized final spread and the Ohnesorge number is strongly dependent on the wettability of substrates.