Overdue invoice? 3 easy 'date math' tips — Business Management Daily: Free Reports on Human Resources, Employment Law, Office Management, Office Communication, Office Technology and Small Business Tax Business Management Daily
Most people, if asked whether a date in an Excel spreadsheet is text or a value, may tilt their heads and give an answer that sounds more like a question. Well, dates are actually numbers. The number associated with a date is the number of days it is past January 1, 1900. Take the date July 4, 2011. To Excel, even though you may see it as 7/4/2011, it is actually 40,728. If I ask, “Can I subtract 40,902 from 40,728?” you would tell me I could. But, if I asked, can I subtract 7/4/2011 from 12/31/2011, you might not be so sure. Well, the answer there is also , yes.
Between two dates With 7/4/2011 in cell A1 and 12/31/2011 in cell B1, I can type this formula in cell C1 to find out that there are 180 days between the 4th of July and New Year’s Eve.
Between date and today If you always want to find out how many days past due an invoice might be, you could use this function TODAY() in cell E2 subtracting the Invoice Due.
Calculating a future or past date If you know that a follow-up call will be made to a client in 45 days, you can add 45 to the Last Contact Date in D1 in a formula in E2.