VARIFORC is a software for advanced processing of first-order reversal curve (FORC) measurements, written in Wolfram Mathematica. VARIFORC algorithms are designed to handle the opposed needs of measurement resolution preservation and noise suppression in most synthetic and natural magnetic materials. These algorithms have been implemented in several FORC processing tools and have become a standard in the scientific literature. VARIFORC also offers specialized plotting options for best rendering of high- and low-amplitude regions and low-dimensional features of the FORC function, as well as tools for quantitative analyses and for the extraction of coercivity distributions. VARIFORC has a modular structure with distinct packages for data import, processing, and graphical rendering. It comes with a user manual containing detailed descriptions of each processing option, along with processing examples and a complete documentation of data formats, FORC protocols, and algorithms. Features: No programming knowledge needed. Compatible with the Wolfram Player Pro platform, a cost-effective alternative to a full Mathematica license (see https://store.wolfram.com/view/app/playerpro/ for pricing). Import raw FORC measurements in all known formats and stack multiple measurements. Correct artifacts such as drift, first-point anomalies, and outliers, and provides several diagnostic parameters to assess measurement quality and instrumental problems. Track temporal changes in repeated FORC measurements (e.g., to document alteration effects). Reject common mode artifacts by performing lower branch subtraction with standard FORC measurement protocols and new protocols that include measurements of the lower hysteresis branch. Calculate the FORC function or other types of first- and second-order derivatives over any rectangular domain, including regions that are only partially filled by data. Supports conventional processing with constant smoothing factor, as well as advanced options for lower hysteresis branch subtraction, de-shearing, variable smoothing factors, and smoothing factor limitation over critical regions, along with heteroscedastic error calculation and significance estimates. Handles all known types of regular and non-regular FORC functions with optimal noise suppression, avoiding smoothing artifacts. Advanced plotting options for best representation of highly contrasting features of the FORC function, including nonlinear color scales, contour lines, and quantile contour lines. Vertical profile normalization for the representation of interaction field distributions. Support measurement de-shearing to remove or simulate the effect of internal fields. Calculate coercivity distributions associated with different FORC measurement subsets (i.e., DCD or backfield demagnetization, irreversible hysteresis, and central ridge). Extract the central ridge regardless of its superposition with other contributions. Supports measurement averaging, subtraction of background contributions, and calculation of measurement differences (e.g., before and after specimen treatment). Stores all processing parameters for traceability and replication on similar samples. Optional GUI interface for the assisted choice of optimal processing parameters.