Subtraction of Time field is not supported yet. The reason is Time represent a spot during a day without specifying which day. And the difference between time values is a timespan. If you want to calculate the difference, you can use use two date fields with Show Time checked, set default value for the two date fields to same value, add a CSS class to the date fields called "showtimeonly" then use custom CSS to hide the date input and picker.

.showonlytime .cf-date-field-date{display:none}

And add another time field with calculation of "=Datetime1-Datetime2"

Sample as following:

Subtraction of time field is supported since Forms 10.3 with bulit-in calcutions: you can use calculation such as =time2-time1 or =SUB(time2,time1) to get the difference between two time fields:

Are there built-in calculations to take, for example, the "Time Difference" field and convert it to a number field? For example, I worked from 8:00 to 9:30 which is 1.5 hours but the time different field above would display as 1:30:00. How can I make that conversion so I can actually perform timesheet functions on hours later?

Does this work with fields in a collection? I can't seem to get it to work.

I cannot get this calculation to work with a table or a collection. :( Very important for a timesheet where you could have a variable number of entries.

Hi Elexis,

Any luck with this one?  I am trying to do the same thing but its not working for me either.

Thank you,

Manny

Sure. I'll share what I wound up going with:

IE. Shift is 8:00 to 5:00. The user would enter 0800 and 0500 in the fields and the calc would work with that best.

$(document).ready(function () {
  
  $('.cf-collection-block').on('blur', 'input', function(){
  //alert('ok cool');
    calcHours();
  });

function calcHours() {
  var beginTime = 0;
  var endTime = 0;
  var pauseTime = 0;
  var grandTotal = 0;
  var totalTime = 0; 

  $('.cf-collection-block ul').each(function () {
    beginTime = moment($(this).find('.beginTime input').val(), 'HHmm');
    endTime = moment($(this).find('.endTime input').val(), 'HHmm');
    pauseTime = parseNumber($(this).find('.pauseTime input').val());
    totalTime = endTime.diff(beginTime, 'hours', true) - pauseTime;
    $(this).find('.totalTime input').change();
    
    $(this).find('.totalTime input').val(totalTime.toFixed(2));
    grandTotal += totalTime;
  });  
  
  $('.grandTotal input').val(grandTotal);       

}
  function parseNumber(n){ 
    var f = parseFloat(n);
    return isNaN(f)?0:f;
  }

});

I'd be glad to share the form, but I can't attach an XML or ZIP. Just leave me an email address, and I'll send it to ya.