Things About Windows 7’s Calculator You Probably Didn’t Know

I love Windows 7’s calculator. In fact, there’s even a calculator button on my keyboard for quick access. Still, it wasn’t until today that I just discovered that there are more functions in this nifty little program than were present in previous versions of Windows. If you explore the program a little, you’ll easily discover these things as well. Microsoft seems to sympathize a lot with people getting ready to get a mortgage and those who are on the road, judging by the new features it added in Windows 7’s calculator app. Shortly, you begin to appreciate the calculator more than you did before you knew about its extensions.

Calculate Difference Between Dates


Go ahead and click the “View” menu in Windows 7’s calculator and click “Date calculation.” The calculator’s window will extend to show you an interface where you can enter two dates. Once you enter them, your computer will calculate how much time has passed between the dates, in two forms. The first form shows you how many years, months, weeks, and days have passed since then. The second form will show you how many days altogether have passed. You’d be surprised how useful this tool is, especially if you want to know how long you were together with someone.

Unit Conversion


Under the “View” menu, you can also find “Unit conversion” – a feature which lets you convert between all sorts of different units. I honestly don’t use this very much, because I usually type “130¬†mph in kph” in a Google search and get a straight answer. You might find it useful, though, considering that everything is there on your computer, even when you’re offline. The Windows 7 calculator’s unit conversion dialog has almost every unit you can think of, save for the highly scientific ones. It includes things like Joules, Watts, BTUs/minute, Fahrenheit, Celsius, you name it! Give it a shot and come back after a few hours to read the rest of the goodies you get.

Calculate Mortgage & Vehicle Lease

What better way to learn about how much a bank wants to screw you over than to have a mortgage calculator handy on your desktop! Thanks to Microsoft (and, perhaps, this article), it might get a bit more difficult for banks to lure people into unreasonably high payments. You can find the mortgage calculator and all the features below this one under the “Worksheets” submenu of the “View” menu.

Now, here’s a trick I’m sure you know, but I’d like to show you anyway. Select “Monthly Payment” in the drop-down list on the top. Enter the value of the house you want to buy under “Purchase Price,” and fill in the rest of the requested information.

That result is your monthly payment for x amount of years. OK, so now I want you to put the value of the monthly payment into the other side of the window (the “classic calculator” side). Multiply the value by 12 and then multiply it again by the amount of years the mortgage will be for.

Yep! That’s the amount you’re going to end up paying for the house in the end. It’s never a pretty number. After that, take a deep breath and add the amount you put for down payment to that.

There’s also a “worksheet” for vehicle lease, similar to this one.

Fuel Economy (In MPG & L/100KM)


If you are on the road frequently, Windows 7 also added some nifty calculations for fuel economy, allowing you to input how many miles/kilometers you traveled and how many gallons or liters of gas you spent. You can find out how much gas you spent on a trip, the fuel economy of your vehicle, or the distance you traveled. My advice: If you really want to economize, walk to a small business nearby.

Before We Say Adieu…

I really hope that you discovered something new today (I certainly did), and find these features useful. Leave a comment below and tell us all about your experience playing with/using the features!

Miguel Leiva-Gomez Miguel Leiva-Gomez

Miguel has been a business growth and technology expert for more than a decade and has written software for even longer. From his little castle in Romania, he presents cold and analytical perspectives to things that affect the tech world.


  1. here’s one thing i would like to know about win 7 calculator: why does the % key get greyed out in scientific mode?

    1. I just realized that. Most scientific formulas do not use percentages, as that is usually assumed for when you are dealing with statistics. However, if you’d like to use percentages in scientific mode, you need only remember the decimal system.

      To find 16% of 98, for example, multiply 98 by 0.16.

      1. Then why is it even there? What kind of idiot programmer would put a button on a calculator that doesn’t do anything? They might as well give us a ‘divide by zero’ button that doesn’t do anything!

        1. I understand your statement, believe me. I’ve been programming for over 7 years and I can say one thing in his/her defense: Programmers often don’t have a say in UI elements when working in a team. There’s another lead for that who plays the role of GUI designer.

          In fact, I find it psychologically sound to gray out the percentage button instead of exclude it totally. A grayed out button tells you that the calculator does have this feature potentially if you change its mode. The exclusion would imply to a person who doesn’t know better that the button will not exist in any other mode or that the person would have to look for it in another location. It’s a legitimate part of GUI design.

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