Why 4 spaces specifically?

It's the most common indentation width in style guides that use spaces. Only exact runs of 4 consecutive spaces are converted; 2-space or irregular indentation won't match cleanly.

Does it affect spaces in the middle of a line, not just indentation?

Yes, the replacement isn't limited to leading whitespace; any run of exactly 4 consecutive spaces anywhere in the text is converted.

Spaces to Tabs Online - Space to Tab Indentation

Overview

Introduction

Switching a codebase or config file's indentation style from spaces to tabs means precisely converting every indentation level.

This tool converts every 4-space run to a tab.

What Is Spaces to Tabs?

A converter that replaces every run of exactly 4 consecutive space characters with one tab character.

It runs entirely client-side as part of this site's String Tools collection, so nothing you paste is ever uploaded to a server.

How Spaces to Tabs Works

A regex matching 4 consecutive spaces is replaced globally with a tab character.

The transformation happens synchronously in JavaScript the moment you type, with no network round trip involved.

When To Use Spaces to Tabs

Use it when converting space-indented source code or config files to tab indentation.

It's a fast way to get the answer without opening a code editor, a REPL, or writing a one-off script just to check.

Often used alongside Tabs to Spaces and Whitespace Remover.

Features

Advantages

Simple, predictable conversion for standard 4-space indentation.

Limitations

Only matches exact 4-space runs; 2-space or inconsistent indentation won't convert as expected.
Doesn't distinguish leading indentation from spaces elsewhere in a line.

Examples

Converting indented code

Input

    indented
    code

Output

	indented
	code

Each 4-space indent becomes a single tab character.

Best Practices & Notes

Best Practices

Verify your source actually uses consistent 4-space indentation before converting, or the result may be uneven.

Developer Notes

The replacement regex is built dynamically as `{width} spaces`, defaulting to 4, so it matches runs of exactly that many consecutive spaces rather than any arbitrary run length.

Spaces to Tabs Use Cases

Converting a space-indented file to tab indentation
Normalizing indentation style across a codebase
Preparing code for a style guide that requires tabs

Common Mistakes

Running this on 2-space-indented code, which won't match the 4-space pattern.

Tips

Use Convert Tabs to Spaces to reverse this operation.

Spaces to Tabs