Question Type: Time-Based Math (Date/Time)


Date/Time based math allows you to calculate a date based on a start date question, and a duration question. This can be useful when calculating estimated completion dates on projects.

It can be difficult to determine when to use Time-Based Math or Duration Math. Simply put, if you want to show a date (e.g. Feb 11, 2019), use Time-Based Math. If you want to show a duration (e.g. 8:30, meaning 8 hours and 30 minutes), use Duration Math

An example of a Time-Based Math (Date/Time) question on an iOS device is shown below:


Form Builder

In the Form Builder, the Time-Based Math (Date/Time) question appears as shown below:


The Question Edit screen for the Time-Based Math (Date/Time) has three tabs: General, Properties, and Help OptionsClosed Help Options are ways to add help content, such as YouTube videos, web pages, text, or images, to questions in a form. Mobile users simply tap the help icon next to a question to see the help that the form designer provided.. This article will go through each of the tabs.



Unique ID

The Unique IDClosed A Unique ID refers to the specific identifier of a question, form page, form section, or Data Destination. Unique IDs are used as reference points when pulling data for conditional logic, Analytics projects, Data Destinations, and Documents. is the reference for the question. For more information on Unique IDs, read: Overview: Unique IDs. It can either be auto-generated based on the question text, or customized.


Restrictions control how your mobile users interact with a question. They can be set on the question itself, or controlled by Conditional Logic.

Required Read-Only Hidden on Device Hidden in Reports
Time-Based Math (Date/Time) ✓ *

* Time-Based Math is Read-Only by default, as the mobile user cannot interact with them.


Properties allow you to set up your question in various ways. Some Properties are due to the Data Type chosen for the question. The Time-Based Math (Date/Time) question type only allows one data type:

  • Range Validation

Calculate a Date/Time

This section allows you to set your source questions for the calculation, and what kind of calculation you are doing. For example, if calculating a projected end date for a construction project, you would want to select Add Duration.


Start Date/Time Question: This dropdown will allow you to select any questions using a Date/Time data type that come before the Time-Based Math question.

Operator: You can add or subtract the duration from the Start Date/Time question to get to your answer.

Duration Question: This dropdown will allow you to select any questions that use a Duration data type that come before the Time-Based Math question.

Help Options

Adding "Help" content to forms gives mobile users access to support and other resources out in the field. Help content is available to users through a button embedded beside a question. Any question in the form can include a link to YouTube videos, web pages, or HTML-formatted work instructions. 

For more information on Help Content, please read: Adding Help Content to Questions