AddDays: A Very Simple Date Calculator

Add days windows app, specify date, number of days to add, and a format

To help my business manager (aka wife) with invoice preparation I wrote a very simple date addition calculator.

You can download it here.


Given a date, it adds a number of days to it, so you can calculate due dates for invoices.

When I told my colleagues about this they each had different but equally 'helpful' alternatives I could have used.

  1. Why not user powershell? (Get-Date).AddDays(50) | clip
  2. What about the built in "Date Calculation" mode in Calculator? (The templates feature of Windows 7 Calculator is pretty interesting by the way)
  3. Why not just use excel?
  4. Why not use the DATEADD function in SQL? Most people have SQL Management Studio open all the time, don't they?
  5. Why don't you use Invoice Place?

I like writing my own software, and the little details are the things I love the best. The moment you change the date, or change the number of days to add, or change the format, the result is immediately copied to the clipboard.

Anyway, if it helps you so be it. No support it offered, and of course I disclaim all responsibility to the best of my ability.

Writing your own solutions to your own problems is very satisfying.

Regarding the special features of 'calc.exe', here's a screenshot of calc in 'Date Calculation' mode (available in Windows 7 and above)


I'm currently writing a book about how to build your first product. If you want to build your first product, please sign up to be notified when the book is available.

(By the way, I read every comment and often respond.)

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