fitramp fits a ramp to a series of nondestructive reads and detects and rejects jumps. The software performs likelihood-based jump detection for detectors read out up-the-ramp; it uses the entire set of reads to compute likelihoods. The code compares the χ² value of a fit with and without a jump for every possible jump location. fitramp can fit ramps with and without fitting the reset value (the pedestal), and fit and mask jumps within or between groups of reads. It can also compute the bias of ramp fitting.