A Windows program (WinPLtb) has been developed to calculate wet–chemical and microprobe pyroxene analyses based on the standard International Mineralogical Association (IMA-88) nomenclature scheme. The program allows the user to enter clinopyroxene, orthopyroxene and associated composition of liquid or whole-rock and some calculated components in the Data Entry Screen as well as loading the Microsoft ® Excel files including pyroxene and liquid analyses. Although, WinPLtb is essetially aimed to estimate the clinopyroxene–liquid and orthopyrpxene–liquid thermobarometers it also calculates the clinopyroxene-based hygrometers and depths where pyroxene-bearing rocks crystallized. Calculation of pressure- and temperature-dependent thermobarometers is carried out using the previously entered input P-T values or calculated P-T values by program depending on the selected options from pull-down menu. The input values for calculations are percentage of clinopyroxene and orthopyroxene analyses, liquid or whole-rock compositions, P (GPa) for temperature–dependent orthopyroxene–liquid thermometers, and T (K)– P (kbar) for clinopyroxene–liquid thermobarometers. All the calculated results by program are stored in an output Excel file. This file can be used for further general data manipulation and graphing purposes. The compiled program described herein is distributed as a self–extracting setup file, including the necessary support files used by program, a help file, and sample data files.