ICSviewer is a tool to convert an exported calendar (.ics-file) into a table-formatted data grid, while calculating the hours you worked. You can load an .ics-file by dragging and dropping it onto the grid or by choosing open from the File-menu. When you load a file it process DTSTART, DTEND, SUMMARY, LOCATION, and DESCRIPTION. The start and end-times are split into two columns and the hours are calculated. Hours are rounded on whole and half hours. You can broaden or narrow the display of the contents of the .ics-file by selecting from-to dates at the top of the screen. You can hide or show columns by (de-)selecting the respective checkboxes and you can set the decimal point for half hours via the small pop-up menu. The file's contents are automatically reprocessed after each change in settings. After playing around, click inside the grid, select all contents via CMD-A, and copy them via CMD-C then paste into an invoice or a spreadsheet.