Apple Calculator stores one number at a time using the memory buttons

The Apple Calculator app — built into every iPhone, iPad, and Mac — has three memory buttons at the bottom of the screen: M+, M−, and MR. These let you save a number while you work on something else, then bring it back later. Unlike a notebook, the calculator forgets what you stored the moment you close the app, so this works best for calculations you finish in one sitting.

The memory feature is most useful when you need to add or subtract from a running total without stopping your current math. For example, if you are splitting a bill and need to add several amounts to a subtotal, you can store the subtotal, then add each new amount to it without losing your place.

Key Takeaways

  • M+ adds the number on screen to whatever is stored in memory; M− subtracts it; MR shows what is stored.
  • The memory buttons only appear in portrait mode on iPhone — rotate your phone sideways to see them.
  • Apple Calculator erases the stored number when you close the app, so it is not a way to save data between days.
  • A small dot appears next to the calculator icon when something is stored in memory, so you know the memory is not empty.
  • If you need to store multiple numbers or save them permanently, use the Notes app or a spreadsheet instead.

Finding the memory buttons on your device

On iPhone, the memory buttons only show up when you hold the phone in portrait mode (tall, not wide). Open Calculator, and you will see M+, M−, and MR in a row at the bottom. If you rotated your phone to landscape mode, the buttons disappear — rotate back to portrait to use them.

On iPad, the buttons are always visible in the bottom left corner of the calculator, whether you hold it in portrait or landscape. On Mac, they appear in the same spot in the Calculator window. The buttons look the same on all three devices: M+ is on the left, M− in the middle, and MR on the right.

How to store a number using M+

Type or calculate the number you want to store, then tap M+. The number stays on the screen, but it is now added to memory. If memory was empty, it is now equal to that number. If you already had something in memory, the new number gets added to it.

For example: you type 50 and tap M+. Memory now holds 50. You clear the screen and type 30, then tap M+ again. Memory now holds 80 (50 + 30). The screen still shows 30, but memory has the sum. This is useful when you are collecting amounts and want to keep a running total without writing it down.

How to subtract from memory using M−

Type or calculate the number you want to remove from memory, then tap M−. The number on screen is subtracted from whatever is stored. The screen does not change, but the memory total goes down.

Example: memory holds 100. You type 25 and tap M−. Memory now holds 75. This is less common than M+, but it is useful if you are tracking a balance and need to deduct refunds or corrections. You might use it when splitting costs and someone needs to be reimbursed a portion of what was already added.

How to see what is stored using MR

Tap MR (memory recall) to see the number that is currently stored in memory. The stored number appears on the screen, replacing whatever was there. You can now use that number in a new calculation, or just look at it to confirm what you saved.

If memory is empty, MR shows 0. If you tap MR and see a number you did not expect, you can clear memory by tapping M− repeatedly until the total is gone, or straightforward close the app and reopen it — closing the app always erases memory completely.

The memory indicator dot and clearing memory

When you store something in memory, a small dot appears next to the Calculator icon on your home screen or in the dock. This dot tells you at a glance that memory is not empty. The dot disappears when memory is cleared.

To clear memory intentionally, there is no dedicated clear button — you have to close the Calculator app entirely. Swipe it away on iPhone or iPad, or close the window on Mac. The next time you open Calculator, memory will be empty and the dot will be gone. If you want to keep the number you stored, write it down or copy it to Notes before closing the app.

When to use memory versus other tools

Memory works well for quick math in the moment: adding up a tip, combining prices while shopping, or keeping a subtotal while you calculate individual items. It is fast and requires no setup.

If you need to store numbers across multiple days, or keep track of more than one number at a time, use Notes or the Reminders app instead. If you are doing complex math with many values, the Numbers spreadsheet app (on iPad and Mac) or Excel (on all devices) gives you more control and lets you save your work. Memory is a convenience for single-session math, not a replacement for these tools.

Frequently Asked Questions

Does memory save when I close the app?

No. Closing Calculator erases memory completely. If you need to save a number, write it down, take a screenshot, or copy it to Notes before closing the app.

Can I store more than one number at a time?

No. Memory holds only one total. Each time you tap M+, the new number is added to what is already there. If you need to track multiple separate numbers, use Notes or a spreadsheet.

What does the dot next to the Calculator icon mean?

The dot means something is stored in memory. It disappears when memory is empty or when you close and reopen the app. It is just a visual reminder that you have a number saved.

Can I use memory on the lock screen calculator?

No. The quick calculator on your lock screen does not have memory buttons. You must open the full Calculator app to use M+, M−, and MR.

What if I tap M+ by accident?

The number on screen gets added to memory. If you did not mean to, tap M− with the same number to undo it, or close the app to erase memory entirely.