[Tex/LaTex] Date calculations

calculationsdatetime

I'm building a LaTeX document that helps me to formulate quotations for my customers.
Since I decided to offer monthly recurring payments I'd like to have payment dates calculated automatically starting from a specific one.
Say, for example, that you have:

\today{}

then I need to have:

  • \today +30 days
  • \today +60 days
  • \today +180 days

and so on…

Is that possible?

EDIT: I ended up using the package advdate because I obtained a more compact result to do this:

% Payment starts in 4 months.
\AdvMonth{4}

% 1 chunk per month -> due date:
\begin{enumerate*}
    \AdvMonth{1} \item due date: \textbf{\today}
        ...
\end{enumerate*}

Best Answer

See the advdate package.

Edit Six years later, I am finally getting around to adding an example. It does what the package says it does.

\AdvanceDate Advances date the specified number of days [an argument in square brackets, defaulting to 1] and sets the result to \today

Two things to notice there:

  • To advance by 30 days, for instance, the syntax is \AdvanceDate[30].

  • The package effectively uses \today as a variable. Which means if you are recording several dates relative to today, you need to advance incrementally. If you want 30 days, then 60 days, you need to call \AdvanceDate[30] twice.

  • Of course, TeX's scoping rules are still in effect. So if you advance \today in a group, the changes end when the group ends. So if you make a table your increments are forgotten at the end of each cell.

Here is an example document, showing both of these:

\documentclass{article}
\usepackage{advdate}
\begin{document}
Today is: \today

Tomorrow is: \DayAfter

30 days from today is \AdvanceDate[30]\today.

60 days from today is \AdvanceDate[30]\today.

180 days from today is \AdvanceDate[120]\today.
\AdvanceDate[-180]
\bigskip

\begin{tabular}{|cc|}\hline
    Relative description & Date \\\hline
    today & \today \\
    tomorrow & \DayAfter \\
    30 days from today & \AdvanceDate[30]\today\\
    60 days from today & \AdvanceDate[60]\today\\
    180 days from today & \AdvanceDate[180]\today\\\hline
\end{tabular}
\end{document}

mwe output

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