The Calculator app is probably one of Apple's most-used apps on the iPhone, yet I always meet people who don't know all the little tricks there are to using it more efficiently. You may know most of them, but there's a chance you don't know every single one or simply forgot about them.
What a "hidden trick" is to some people might be obvious to others, so feel free to skip right by the ones you already know in the below list. This roundup is for everyone, from a total smartphone newbie to somebody who's owned iPhones since iPhones were a thing, and even professional mathematicians. For the most part, I've sorted it from the easiest, most intuitive actions to the more advanced ones, so skip ahead if you need to.
OK, so this is pretty obvious...or is it? Yes, you can tap the Calculator app icon on the Home Screen, but there are other ways to open Calculator. Here are just some of the ways you could do it:
- Tap its icon on the Home Screen.
- Tap its icon in the App Library. (iOS 14 and later.)
- Tap its icon in Search.
- Tap its icon in Control Center.
- Say or type "Calculator" to Siri or Hey Siri.
- Double- or triple-tap the back of your iPhone. (iOS 14 and later — see Tip 16 below.)
- Open it from a custom shortcut via a Home Screen or Today View widget, the Shortcuts app, Siri or Hey Siri, Search, or double- or triple-tap the back of your iPhone.
- Have it open by itself using various Shortcuts automation scenarios. (See Tip 17 below.)
You've most likely stumbled upon this by accident, but I know some people who've never turned their iPhone sideways except to watch Netflix or Hulu. So rotate your iPhone into landscape orientation, and the calculator will change automatically from the standard calculator (for basic arithmetic calculations) to the scientific calculator (for exponential, logarithmic, and trigonometric functions).
You'll find more advanced options like cosine (cos), tangent (tan), square root (v), natural logarithm (ln), and the pseudo-random number generator (Rand) that are most useful for science, engineering, and advanced mathematics.
If you meant to type 523 instead of 532, "Shake to Undo" won't remove your last few digits since that feature is disabled in Calculator. But there's an easier way to remove digits entered. Just swipe either left or right on the number field, or really, anywhere above the keys, and the last digit will be deleted. If you need to get rid of two, swipe again. Three? You get the picture. If it's the whole number you need to redo, see the next tip.
Whenever you type an entire number in that's wrong, there's a super quick way to fix the mistake. Again, "Shake to Undo" won't work since it's disabled in Calculator. Instead, you can just clear the display using the "C" key, which stands for "Clear." It won't erase all of your progress — just the last entry. So if you entered 1,242 x 324 but meant it to be 1,242 x 423, hit "C," then enter 423 and continue with your calculation.
If you do need to start from scratch, you'll want to use the "AC" key, which stands for "All Clear." If you don't see an "AC" button, that's because it only appears after you've cleared the display, so you'll have to hit "C" first before "AC" will appear in its place. Tap that to start all over again. (Note that force-quitting Calculator won't work since it will still remember your last result.)
Apple's help pages only mentioned one way to copy and paste numbers in Calculator, but there are actually many different ways to go about it. If you're trying to paste a number in, you'll only see a "Paste" option if you already have a number stored in your clipboard.
- Tap-and-hold the number currently displayed. Tap "Copy" in the menu to copy the number, or tap "Paste" if you have a number stored in your clipboard that you want to use in the calculation.
- Double-tap the number currently displayed. Tap "Copy" in the menu to copy the number, or tap "Paste" if you have a number stored in your clipboard that you want to use in the calculation.
- Tap the display with three fingers. Tap the Copy icon (middle button) to copy the number currently displayed, or tap the Paste icon (to the right of Copy) if you have a number stored in your clipboard that you want to use in the calculation. (iOS 13 and later only.)
- Pinch the display with three fingers. This will copy the currently displayed number.
- Tap the display with three fingers and spread them. Think of it as the opposite of a three-finger pinch. This will paste the currently displayed number. (iOS 13 and later only.)
If you're still in the Calculator app and need to copy the current result, you would just use one of the options above. However, if you're no longer in the Calculator app, there are still a few ways to do it.
- Swipe open the Control Center, then long-press the Calculator icon.
- Long-press the Calculator app icon on the Home Screen.
- Long-press the Calculator app icon in the App Library.
- Long-press the Calculator app icon in Spotlight Search.
Either way, you'll see an option to "Copy Last Result," and it will list the last result, so you know that it's the right one. Your last result should even show up after force-quitting Calculator.
Now that we've mentioned Spotlight Search, it's good to know that you can perform mathematical calculations right from it instead of opening the Calculator app at all. To open Search, swipe down on your Home Screen or open the Today View either by swiping to the far left side of your Home Screen or Lock Screen. In iOS 16, you can also tap "Search" above the dock where you'll the page dots are.
Then, enter in your equation or formula. A box directly underneath the Search field will appear with your result. Tap that, and it'll take you right to Calculator with the result already entered, in case you want to continue your math problem there.
For the complete list of calculations you can perform in Spotlight, check out our guide on using Spotlight as a calculator on the iPad, which doesn't have a stock Calculator app like iPhone does.
You won't be able to perform advanced calculations since the keys limit you on your keyboard, but that's solvable by installing a keyboard with more calculator functions. Third-party keyboards you can use in Search include Numboard – Scientific Keyboard, Calcul Keyboard, Calculator KeyBoard, Calculator Keyboard - Faster, and SciKey - Scientific Keyboard. However, not all mathematical operators, symbols, variables, constants, and functions are supported in Search, so you may still need to open Calculator if you see ones that don't work.
- "What's 74 times 14?"
- "What's 28 percent of 225?"
- "What's one-third of 456?"
If you try to ask it more advanced problems, like algebraic expressions, Siri may not use Calculator to give you results. Instead, it may use WolframAlpha or Safari to get you solutions or links to possible answers. In other cases, it may give you a wrong answer using Calculator because it didn't understand the problem, such as "What's 15% of 45% of 1.4?" (it's 0.0945, not 6.75).
When using Calculator, most of you will enter a number, hit a symbol, type in some more numbers, hit another symbol, etc. But that's not the only way to do it. Let's say you want to convert % into decimal form. Normally, you would type the number, then hit the % key. However, you can also tap-and-hold the % key first, then type the number and let go of the % key to get the same result. Try it with other buttons and symbols, and you might just find that it's faster in some cases.
If you're new to scientific calculators, this may come in handy. Since all of the options won't fit on the keyboard, you can tap the "2nd" key to change some of the other keys. For instance, sin will turn into sin-1, ln into logY, eX to yX, etc.
In the scientific calculator, there's a "RAND" key, which is a random generator function that produces a number between zero (0) and one (1). More specifically, it's a pseudo-random number because software cannot randomly generate the outcome of unpredictable natural phenomena like rolling dice or measuring atmospheric noise. With it, you can perform a calculation such as emulating rolling dice. This blog post can explain it better than I can.
If you want to know how the number is spoken, you can make your iPhone speak it to you. In the Calculator app, you can tap-and-hold the current number or double-tap it, then select "Speak" from the menu to hear it spoken as words, or "Spell" to have each digit and symbol spoken individually in order. If you don't see these menu options, enable it via the "Accessibility" preferences in Settings:
- Spoken Content –> Speak Selection (iOS 13 and later)
- Speech –> Speak Selection (iOS 12 and older)
There aren't many ways to change the Calculator's colors, but that doesn't mean it's impossible. Dark Mode in iOS 13 and later doesn't affect it since the Calculator already has a dark theme, and Smart Invert does nothing to the theme either. However, you could use Classic Invert and Color Filters to make it look how you want. For Classic Invert, in the "Accessibility" preferences, go to:
- Display & Text Size –> Classic Invert (iOS 13 and later)
- Display Accommodations –> Invert Colors –> Classic Invert (iOS 12 and older)
For Color Filters, in the "Accessibility" preferences, go to:
- Display & Text Size –> Color Filters (iOS 13 and later)
- Display Accommodations –> Color Filters (iOS 12 and older)
Classic Invert changes the look to an inverted color scheme, while Color Filters gives you lots of options, from Grayscale to Red/Green to Green/Red and Blue/Yellow, and you can even tint the screen with any hue. To make it more useful, add Classic Invert and Color Filters to the "Accessibility Shortcut" in the "Accessibility" preferences. Then, just triple-click the Side or Home button to activate it when in Calculator, then do it again when leaving Calculator.
If you like the Shortcuts app, you can use it in iOS 14 and later to create an automation that will change Calculator's color scheme every time you open the app, then return it to normal whenever the app's closed. I won't go over the process here, but you can see how to build automation in our full guide. Below, you can see Classic Invert in action (left) and Grayscale (right).
Apple introduced Back Tap in iOS 14, an accessibility feature that lets you double- or triple-tap the back of your iPhone 8 or later to trigger an action of your choice. To make it open up Calculator, you would create a new shortcut and add one action: "Open App," with "Calculator" being that app. Then, go to Settings –> Accessibility –> Touch –> Back Tap. Choose either "Double Tap" or "Triple Tap" and select the shortcut you created. Now, whenever you tap your iPhone, Calculator will open.
While we're on the topic of shortcuts, that brings us to our last tip. The Shortcuts app will let you build almost any trigger-action scenario, automation, or task, and the Calculator has a few actions that you can incorporate into your workflows. I won't go into how to use each since each could be a whole article, but I'll include their descriptions.
- Calculate: Performs a number operation on the input and returns the result. (Input: Boolean, Workout sample, Text, File size, Time interval, Date, Blood pressure, Number, Health sample, Current Amount, Measurement — Results: Numbers)
- Calculate Statistics: Calculates statistics on the numbers that are provided as input. (Input: Booleans, Workout samples, Text, File sizes, Time intervals, Dates, Blood pressures, Numbers, Health samples, Current Amounts, Measurements — Results: Numbers)
- Calculate Expression: Evaluates the mathematical expression in the given input string and outputs the result as a number. (Input: Text — Output: Number)
- Format Number: Formats a number into text. (Input: Booleans, Numbers — Result: Text)
- Get Numbers from Input: Returns numbers from the previous action's output. (Input: Booleans, Workout samples, Text, File sizes, Time intervals, Dates, Blood pressures, Numbers, Health samples, Currency Amounts, Measurements — Result: Numbers)
- Number: Passes a number to the next action. (Result: Number)
- Random Number: Passes a random number between the given minimum and maximum to the next action. The minimum and maximum numbers are included as possible results. (Result: Number)
- Round Number: Rounds the number(s) passed into the action. (Input: Numbers — Result: Numbers)
Other related actions:
- Base64 Encode: Encodes or decodes text or files using Base64 encoding. (Input: Text, Files — Result: Text)
- Convert Measurement: Converts the measurements passed into the action to the specified unit. (Input: Measurement, Air Pollutant, Trip Info — Result: Measurement)
- Count: Counts the number of items, characters, words, sentences, or lines passed as input. (Input: Anything, Text — Result: Number — Note: This is just like the Count in Sesame Street, but instead of a vampire, it's a Shortcuts action.)
- Format File Size: Formats a file size into text. (Input: File sizes, Numbers (A file size from another action, or a number of bytes) — Result: Text — Note: 1000 bytes are shown as 1 KB.)
- Measurement: Passes the specified measurement (including number and unit) to the next action. (Result: Measurement)
While Calculator isn't an app that lets you change its app icon itself, you can still customize its appearance on your home screen.
To do so, you need to set up a shortcut that opens the Calculator app (you just need to add the "Open App" action and set the app to Calculator), then change that shortcut's icon before or after adding it to your home screen as a bookmark. Remove the real Calculator app from your home screen, and any time you tap the bookmark, Calculator will open.
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