How to subtract days, months or years from a date?

This is a common question from Google Forms users who set a deadline, a reminder or an earliest start date. You may need a date that is some days or months before another one. Counting back by hand is easy to get wrong, especially across months and years and Google Forms has no option to do it. With Formfacade, you can use the SUBTRACT function to subtract days, months or years from a date and your users will see the new date as soon as they enter the first one. Even better, nobody has to count back across a month or a year again.

Let's start. Create your form and follow the steps below.

Subtract days from a date

  • On the page that opens, name your form, click Build form and click Proceed. It can take about a minute.
  • You will land on the form's "Preview" tab.
  • Click on "Edit" tab
The tabs Edit, Preview, Share and Responses, with Edit marked
  • Click on the + icon (Add field) in the toolbar on the right. A new question will be added.
  • Enter "Input date" as the question and select Date in the question type list
  • Click on the + icon again
  • Enter "Subtract 7 days from input date" as the question and select Date in the question type list
The toolbar on the right of the Edit tab, with the + icon marked
Click on the ⚙️ icon at the bottom right of the question.
The form in Formfacade, with the EDIT tab, the Subtract 7 days from input date question and its gear icon marked
Field settings screen will be displayed. Select the "Answer" tab and write the formula to subtract days from a date.
The field settings panel with the Answer tab and the Calculate box marked

SUBTRACT function

You can subtract days from a date by specifying "days" as the term in the SUBTRACT function.
Syntax:
subtract(number_of_days, "days")
Example usage:
TODAY().subtract(30,"days")
Inputdate.subtract(7,"days")
Note: To enter Inputdate, type @ in the calculate option and select the Input date question from the list. If no list appears on your form, make your form here instead: name it, click Create form and click Proceed, close the Assign points dialog and add these questions. The @ list opens on a form made there.
Write the formula in the Calculate option as shown below. Click Save.
The Calculate box with the Input date field and .subtract(7,"days")

Subtract months from a date

You can subtract months from a date by specifying "months" as the term in the SUBTRACT function.
Syntax:
subtract(number_of_months, "months")
Example usage:
TODAY().subtract(6,"months")
Inputdate.subtract(2,"months")
Add another date question the same way, click on the ⚙️ icon and write the formula in the Calculate option as shown below. Click Save.
The Calculate box with the Input date field and .subtract(2,"months")

Subtract years from a date

You can subtract years from a date by specifying "years" as the term in the SUBTRACT function.
Syntax:
subtract(number_of_years, "years")
Example usage:
TODAY().subtract(1,"years")
Inputdate.subtract(5,"years")
Add another date question the same way, click on the ⚙️ icon and write the formula in the Calculate option as shown below. Click Save.
The Calculate box with the Input date field and .subtract(5,"years")
As soon as the user enters the input date, the form shows the new dates. Until then, they show dates around 1970, because an empty date counts from 1970.
The Date functions form with an input date of 1 November 2026 and the dates 7 days, 2 months and 5 years before it

Summary

If you need a date that is some days, months or years before another date, Google Forms cannot calculate it. With Formfacade, you can use the SUBTRACT function in the Calculate option and the new date will be displayed as soon as the user enters the first date. Create your form and complete the steps above. If you have any questions, write to support.

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