Irradiation-induced swelling in 20% cold-worked Type 316 stainless steel can be described by the use of a bilinear equation with three governing parameters. These parameters are R, a steady-state or linear swelling rate, τ, an incubation parameter denoting a fluence beyond which the linear, or high swelling, portion of the curve is attained, and a, a curvature parameter designating the degree of sharpness by which the equation curves from a region of low swelling to a region of higher swelling. This equation is intended for inclusion in the Nuclear Systems Materials Handbook and was developed with data extending to fluences around 16 × 1022 n/cm2(E> 0.1 MeV). The data set utilized includes first core Fast Flux Test Facility (FFTF) cladding specimens and specimens from several non-FFTF lots of cladding, in addition to supplemental data from an air-melted heat of steel. Heat-to-heat variations in swelling are significant in this material, and separate incubation parameters were developed for different lots of cladding.