Why is my custom function not showing in Google Sheets autocomplete?

You have a custom function in Google Sheets that runs correctly when you type it manually, but it does not show up in the formula autocomplete suggestions as you type the equal sign and the first few letters.

This guide walks through the most common reasons that happens in real projects and gives you a short checklist to make your function eligible for autocomplete.

Why is my custom function not appearing in Google Sheets autocomplete?

Google Sheets only shows functions in autocomplete if they come from the active spreadsheet and follow the rules that Apps Script uses for custom functions. If the script is saved in the wrong place, missing the JSDoc annotation, or not yet loaded by the sheet, Sheets will still let you call the function by name, but it will not appear in the suggestions list.

Consider this example function, which matches Google's documentation:

/**
 * Doubles the given number.
 *
 * @param {number} value The number to double.
 * @customfunction
 */
function multiplyByTwo(value) {
  return value * 2;
}

If you paste this into the script editor and type =mult in a cell, Sheets should suggest MULTIPLYBYTWO after it has indexed the function. If it does not, go through the sections below one by one.

Is my Apps Script project actually linked to this sheet?

Autocomplete only knows about custom functions that live in a script project bound to the current spreadsheet. If the function lives in a standalone Apps Script project that is not attached to the sheet, Google Sheets will never list it in autocomplete.

To confirm that the project is linked to the sheet:

• Open the spreadsheet where you want to use the function.
• In the menu, go to Extensions > Apps Script.
• Make sure you see your multiplyByTwo function in this editor.
• If you opened the script from script.google.com first and then connected the sheet later, create a new bound project from the sheet instead and copy your code over.

If the function is not in the bound project opened from Extensions > Apps Script, Sheets will not include it in autocomplete even if the code looks correct.

Did I add JSDoc and save the script correctly?

Google Sheets uses the JSDoc comment directly above your function to recognize it as a custom function and to show helpful argument hints in autocomplete. Small formatting mistakes in the comment can stop autocomplete from listing it.

Double check these details:

• The comment starts with /** and ends with */, with no blank line between the comment and the function keyword.
• The @customfunction tag is inside that comment block, on its own line.
• Each parameter has a matching @param line with the correct type, for example @param {number} value The number to double..
• The function is written with a standard function declaration like function multiplyByTwo(value) { ... }, not as an arrow function assigned to a variable.
• You have clicked Save in the Apps Script editor after changing the comment.

After saving, close the Apps Script tab, refresh your spreadsheet, and then try typing the function name again in a cell.

Did I authorize the script and give Sheets a chance to index it?

Custom functions that call services which require authorization sometimes do not appear in autocomplete until you have run them once and granted permissions. Sheets also caches metadata about functions, so there can be a short delay between saving the script and seeing the function in suggestions.

To rule out authorization and caching issues:

• In the Apps Script editor, run a simple function or menu setup that calls your code so the authorization dialog appears.
• When prompted, choose Execute as you, review the scopes, and authorize the script.
• Return to the spreadsheet, reload the page, and wait a minute.
• Start typing your function name again and watch for autocomplete suggestions.

Some developers also create a tiny custom menu in onOpen that calls their function one time. This can be a practical way to trigger authorization and encourage Sheets to refresh its view of the script.

Could the function name or environment be confusing Google Sheets?

When autocomplete still does not show your function, even though it runs when you type the name manually, the problem is often the function name, the browser state, or the account configuration.

Work through these quick checks:

• Rename the function to something simple. Use only letters, numbers, and underscores, and avoid names that are very close to built in functions. For example, =MYDOUBLE(2) is safer than a name like =DOUBLE.
• Use a single Google account in the browser. Sign out of other Google accounts or use an incognito window so the sheet, the script, and the autocomplete all run under the same identity.
• Confirm you are using a supported browser. Use a current version of Chrome if possible and clear cached script files if suggestions look stale.
• Check that the script is not extremely large. In very large projects autocomplete can lag or fail to show every function. If your script file is huge, try moving the custom function into its own smaller file inside the same project.

After each change, save the script, reload the spreadsheet, and try typing the function name again.

What if my function still does not show in autocomplete?

In some cases, there is a delay on Google's side before new custom functions become visible in autocomplete. During that time, you can still use the function by typing the name in full.

If autocomplete never shows it, but the function runs correctly when you enter it manually, your setup is valid and the issue is only with suggestions. That is frustrating for discoverability, but it does not block your sheet from using the function.