Build 4.9.0.3 of xlsgen adds direct support for elapsed time, i.e. time used with either hour, minute or second enclosed in square brackets, as in [hh]:mm:ss in order to display out of boundaries numbers.

Using elapsed time, you can display with 30:00:00 the fact that you've had an event lasting 30 hours, notably bypassing the implicit limit of 24 hours. All it takes is to pass 30:00:00 as a date and apply a number format of the form [h]:mm:ss.

It works like this :

worksheet->Cell[2][1]->HtmlDate = L"<div format=\"[h]:mm:ss\">30:00:00</div>";

In Excel this is effectively stored as an elapsed duration of 30 hours, not a display artefact. Which means that formulas that depend on it can do their calculations properly.


Square brackets can apply to minutes or seconds as well, to represent an arbitrary duration in minutes or seconds.

This feature has been in Excel just about forever, but it was not added to xlsgen until now.