Calculator’s 7 hidden features
Mac Tip #446, 21 July 2010

Apple’s Calculator.app has some interesting, if hidden, features. Check these out.

Calculator.app — standard view, with Paper Tape.

Calculator speaks

The standard Calculator screen is very basic: add, subtract, divide and multiply, using the Memory functions if you need to.

One nifty feature is that Calculator can speak the keys you press, and the result. Go to the Speech menu and check Speak Button Pressed and Speak Result. Provided you have the volume up, you’ll hear each number and operation key you press, and the result of the calculation. It’s very handy as a check on what you’re doing.

Show Paper Tape

Not sure if you pressed 4 instead of 3? Once you’ve pressed a second button you have no record of what came before. That’s where the Paper Tape comes in: it keeps track of everything you did. Choose Show Paper Tape from the Window menu. A new window appears that displays the result and the operations that led to it.

Save the Paper Tape as a text file by choosing Save Tape As… from the File menu.

Separate the thousands

Change the Thousands Separator.

If you’d like it to, Calculator can use the System default Thousands Separator when you have those larger numbers. Choose Show Thousands Separators from the View menu.

In my case it adds a comma, as that’s what we use in New Zealand. If you’re in a European country it should show a dot.

To change the Thousands Separator go to System Preferences > Language & Text > Formats. Click the Customize… button beside the Numbers section. A window appears where you can select separators for Numbers and Currency.

How many decimal places?

You may or may not need accuracy to several decimal places. Set any number of decimal places from 0 to 15 by choosing the Decimal Places item from the View menu.

Scientific, Programmer and RPN modes

Quite honestly, my maths isn’t up to being able to use advanced modes on the Calculator, but they are there if you need them. Look under the View menu.

Check the Help menu for information about RPN mode.

If you choose Scientific or Programmer mode the Calculator totally changes its appearance to include the various keys you need, with a larger display area.

Tell us in the Comments at the website your favourite Calculator features.