Abstract A procedure for calculating the energy and force of capillary interaction between two floating spherical particles of submillimeter size attached to a liquid-fluid interface is proposed on the basis of a general expression for the grand thermodynamic potential of the system. The latter takes into account the gravitational, wetting, and meniscus surface energies. For large interparticle separations the derived equations reduce to the asymptotic formulas derived by Chan et al. (J. Colloid Interface Sci. 79, 410 (1981)). The effects of interfacial tension, particle size, density, and contact angle on the capillary interaction are investigated. The results of the energetical and force approaches to the capillary interactions turn out to be in a very good quantitative agreement.