Calculate the number of days between today and another date

Dates can be tricky to deal with in Excel. That said, since you need to track when certain things happened in HMIS, it’s helpful to learn how to deal with some of the date functions in Excel in the course of tracking things.

For this post, though, we’re just going to learn how to compare a date to today.

Let’s say you have 10 active clients, and you are wondering how long each of them has been on your roster.

And you are curious how many days, weeks, or months each client has been active in your roster (assuming the above dates are accurate).

What’ll you need to do is subtract today’s date from the project start date. Excel has a TODAY function built in, which will save you from typing in the date in the correct format and continually updating as the days change. 

So, the formula is:
=TODAY() – B2.

This, unfortunately, only gives you the number of days between today and the project start date.

To avoid having to do some mental math, you can take that formula and divide it by 30 to approximate months. The formula to break this down to months would be:

And, of course, you can break it down even further by dividing it all by 365. In which case, the formula for that is:

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