Does this send my code anywhere?

No. Reindenting runs entirely in your browser.

Why not use clang-format?

clang-format is a native binary that isn't available in a browser sandbox. This tool instead reindents by tracking brace nesting depth, which fixes common formatting drift without needing a C toolchain installed.

What indent size does it use?

A fixed 4 spaces per nesting level, always spaces rather than tabs. clang-format's actual width depends on your project's .clang-format file, so if your project specifies a different width, the two won't match.

Will it warn me about unbalanced braces?

Not explicitly. Nesting depth is clamped at zero so an extra closing brace can't push it negative, but the tool doesn't flag the imbalance. If the final line's indentation doesn't return to zero, that's a sign a brace is missing somewhere.

C Formatter - Format C Online

Overview

Introduction

C code pasted from documentation or an old file often has indentation that no longer matches its brace structure.

This tool reindents each line based on `{ }` nesting depth, entirely in your browser, without requiring a native compiler.

What Is C Formatter?

A lightweight reindenter that tracks brace, parenthesis, and bracket depth line by line and re-indents accordingly.

It's a whitespace-only pass: tokens, strings, and logic are never touched, only leading indentation.

How C Formatter Works

Each line is scanned for `{}/()/[]` characters to compute a running nesting depth.

Lines that start with a closing brace are dedented one level before printing, matching their opening brace.

When To Use C Formatter

Use it when a C snippet's indentation has drifted after manual edits.

It's a quick visual check that braces are balanced before compiling.

Often used alongside Java Formatter, Go Formatter and Rust Formatter.

Features

Advantages

Runs entirely client-side with no compiler required.
Fixes indentation drift instantly for typical brace-delimited code.
Handles arbitrarily deep nesting without any configuration needed.

Limitations

Not a real parser: brace characters inside string/char literals or comments still affect depth.
For rigorous style enforcement, use clang-format locally.

Examples

Drifted indentation

Input

int main() {
printf("Hello, world!\n");
return 0;
}

Output

int main() {
    printf("Hello, world!\n");
    return 0;
}

Content inside the function body indents one level deeper, matching the opening brace.

Best Practices & Notes

Best Practices

Use this for a quick cleanup pass, then run clang-format locally for rigorous style enforcement.
Check whether the final line's indentation returns to depth zero, that's a quick sign no closing brace is missing.

Developer Notes

Implemented as a single-pass line scanner that tracks a running brace/paren/bracket balance; it does not tokenize strings, char literals, or comments.

C Formatter Use Cases

Quickly cleaning up indentation in a pasted C snippet
Spotting an unbalanced brace by eye before compiling

Common Mistakes

Relying on this for production formatting instead of a real tool like clang-format.
Assuming brace characters inside string or char literals are ignored, they aren't; the scanner counts every `{`, `}`, `(`, `)`, `[`, or `]` regardless of context.

Tips

If output looks wrong, check for a string or char literal containing an unmatched brace character.
Diff the reindented output against your original before committing it, so you can see exactly which lines shifted.

C Formatter