Xlfert is a Microsoft Excel application that analyzes the spread pattern of a fertilizer spreader. Xlfert is derived from a legacy DOS program called FERT developed by Randy Loper at the Mississippi Cooperative Extension Service of Mississippi State University. Xlfert takes the data gathered from a spreader test and interpolates it using the cubic spline function from XlXtrFun, a library developed by Scott Allen Rauch of Advanced Systems Design and Development, to produce a smooth initial pattern. The interpolated data is then overlaid to simulate the "racetrack" and "up/down" methods of spreading to produce composite patterns of which the analyses are based on. Summary statistics including maximum, minimum and average pounds per acre, coefficient of variation, and standard deviation are calculated for both methods. This program also graphs the overlay data for the swath width(s) that the user selects.