A set of algorithms is proposed to retrieve the size of spherically symmetric particles from the measured intensity of angular scatter data. Of special interest are low-contrast particles whose real part of the index of refraction is between 1.03 and 1.09 and whose size $ka$ is constrained so that $\pi ⩽ka⩽16\pi$ , where $k=2\pi ∕\lambda$ and a is particle radius. Several algorithms are evaluated and compared that are based on either simple matching to the Mie theory predictions or inverse tomography methods. In the tomography methods, a previously proposed algorithm [ Opt. Express. 15, 12217 (2007) ] was used after estimating the phase of the scattered data or adapted to use intensity-only data. In order to ensure stability, all algorithms’ performance was evaluated in the presence of moderate noise. The performance varied as a function of particle size, refractive index, and algorithm. Results suggest that a scattering device that collects only the angular scatter that is perpendicular to the polarization of incident light, usually denoted as $S_1$ , can be used to accurately estimate the size of homogeneous, low-contrast, spherical particles whose diameters are close to the wavelength of the incident light.