Frequently, in field and laboratory studies of wave-generated bed forms on beds of sandy sediments, both large and small wave-generated ripples (LWRs and SWRs) are observed and in some situations may be superimposed upon one another. The present paper examines relationships between measured wave conditions and the geometry of LWRs and SWRs and shows that existing empirical equations used to predict the dimensions of SWRs perform badly for LWRs. To address this problem, relationships found between ripple geometry and the wave Reynolds number are used as the basis for new expressions for prediction of ripple height, wavelength, and steepness that improve the accuracy of existing approaches for both LWRs and SWRs. The present results indicate strongly that SWRs and LWRs are related and their superposition in certain conditions reflects the time lag between the response of the bed to changing hydrodynamic conditions. They must be considered therefore when estimating the total bed roughness in a range of practical engineering and numerical modeling applications.