Crystals growing in an undercooled or supersaturated system have a shape given by the solution of an integro-differential equation (boundary integral). A new analytical solution of this nonlinear equation is found in the limit of large thermal and chemical Peclet numbers. Based on the saddle-point technique for a Laplace-type integral, our solution describes the tip region of crystals, which is close to a globular and circular shape in the three-and two-dimensional cases. Corresponding to various growth modes and Peclet numbers, the boundary integrals and crystal tips are listed in a table. A special case of chemical dendrite growing in a binary isothermal system is specially analyzed.