In this paper, a theoretical model is introduced and an analytical expression is obtained for the height-averaged velocity of the outward flow inside thin drying droplets for the case the convective Marangoni flow exists. The velocity is also measured by tracking the motion of fluorescent microspheres in the drying droplets. The experimental observations show that a region of constant height-averaged velocity exists and the reciprocal of the velocity decreases nearly linearly with time over the pinning stage. Such variances of the velocity are different from the previous studies and are well explained by the present model. Furthermore, analytical expressions are established for the growth rate of the deposit ring and for the total ring mass upon drying. The results are likely to enrich the knowledge about the evaporating droplets and may provide a potential means to predict and control the evaporation-driven deposition and assembly of colloids and other materials. (C) 2014 Elsevier Ltd. All rights reserved.