How to Type the Phi Symbol (Φ)

The capital and lowercase phi symbols, at least to my eye, are quite similar. The sole difference is how much of the stem the circle leaves exposed.

Nevertheless, these symbols have different meanings, and it's important to know how to type each. In data centers, for example, you'll frequently come across the small letter Greek letter phi (ɸ) used to indicate phase. While the capital letter phi (Φ) is used to indicate a phased clock signal in an electrical circuit.

This article will go over methods of inserting both the small letter and capital letter phi symbols on the Windows PC, Mac, and on the iOS or Android smartphone.

How to Insert the Phi Symbol on a Windows PC

In Windows, each special character has its own Alt code number. The number assigned to the small letter phi symbol is 237. The capital letter phi symbol is 232.

Hold down the Alt key and type the numbers 237 or 232 in sequence, using the numeric keypad. If you don’t have a numeric keypad, it may be necessary to press the Fn key to gain access to the numbers found across the top of the keyboard.

With Number Lock selected and using the numeric keypad:

If you’re using Microsoft Word, you have several additional options:

Option 1 for Typing the Phi Symbol in Microsoft Word

In Word for Windows, you can use the Alt + X Unicode shortcuts. Type 03C6,then Alt + X for ɸ. Type 03A6,then Alt + X for Φ.

Option 2 for Typing the Phi Symbol in Microsoft Word

From the menu across the top of the screen, select Insert > Symbols > More Symbols. This will bring up a selection of symbols in a grid. In the upper right-hand corner, under Subset, select "Greek and Coptic." Find the correct phi symbol and double click to insert.

Phi Symbol

How to Insert the Phi Symbol on a Mac

Mac OS neglected to include a keyboard shortcut for typing the small or capital letter phi symbols. However, this is easily remedied. Here are three options:

Option 1 for Inserting the Phi Symbol on a Mac

Highlight ɸ or Φ, copy it, then paste it in the correct place. If you’re only going to use phi a single time, this is the easiest technique.

Option 2 for Inserting the Phi Symbol on a Mac

Click on Insert >Emoji & Symbols. This will open the Character Viewer. In the search field enter "phi." This will present you with a variety of phi symbols. Be sure that the insertion point is in the correct spot in your document, then double click on the most appropriate one.

Option 3 for Inserting the Phi Symbol on a Mac

For more frequent phi users, text replacement works best.

First, copy the desired phi symbol from this page. Then open System Settings and scroll down to Keyboard, select it. Under Text Input, click the Text Replacements button. This will open a dialog box that will allow you to create an automatic text replacement. Click the + symbol. Depending on which you are version of phi you need:

Now whenever you type "low-phi" or "hi-phi," the phrase will be replaced with the appropriate symbol. This will sync across devices connected to your Apple ID.

How to Insert the Phi Symbol on an iPhone or iPad

The default keyboard in iOS doesn’t include either phi symbol. The quickest and easiest way to insert it into text is to copy and then paste it into your document.

However, if you need a more robust solution, iOS has a Text Replacement function.

First, copy the appropriate phi from this page. Then navigate to Settings > General > Keyboard > Text Replacement. Hit + in the upper right corner, paste the phi symbol into the Phrase field, and then type "low-phi" or "hi-phi" as the shortcut. Click Done.

Now, when you type the replacement text, it will be replaced with the specified symbol. Conveniently this shortcut syncs across all of the Apple devices associated with your Apple ID.

How to Insert the Phi Symbol on an Android phone

The default keyboard on Android (Google’s Gboard) doesn’t make space for phi. Short of downloading an app that allows keyboard customization, the simplest way to insert a phi symbol is to copy it from this webpage and paste it into your text.

However, if you’re likely to use the symbol with any frequency, you can add it to your Personal Dictionary with the following method:

Now, when you type the replacement text it will automatically change into ɸ or Φ, depending on what you chose.

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