A PMDX file is a spreadsheet file created by PlanMaker, a spreadsheet program included with Softmaker Office. It stores data in cells arranged in a grid of rows and columns. PMDX files also support cell formatting, formulas, charts, and multiple sheets.

PMDX file open in SoftMaker Office PlanMaker 2018 PMDX files are saved in a proprietary format and are the main file type associated with PlanMaker, a spreadsheet application similar to Microsoft Excel, which is included with Microsoft Office. PMDX files are used similarly to how .XLS and .XLSX files are used by Microsoft Excel. A PMDX file is created to store a spreadsheet and can be closed and reopened for further editing. PMDX files may be created from a .PMV and .PMVX templates or XLS and XLSX spreadsheets. They may also be converted to various formats in PlanMaker, including .PDF, XLS, XLSX, .XLSM, .XLTX, .XLTM, .XLT, .TMD, and .RTF. NOTE: PMDX files replaced .PMD files, which were used to store spreadsheets by older versions of PlanMaker.