The use of databases in geotechnical engineering allows engineers to make a priori estimates of soil behaviour. Based on a study of the published literature, a database of 20 clays and silts is presented that allows predictions to be made of the strain-dependent stiffness of fine-grained soils, based on simple soil parameters. The significance of rate effects is discussed and corrections are made. The use of a reference strain γ_ref to normalize shear strain values γ in relation to modulus reduction G/G₀ is discussed. Empirical formulations are presented based on a rigorous regression analysis, and design charts are constructed.