Code Line Counter

Count total lines, code lines, comment lines, and blank lines. Auto-detects language from comment syntax.

Last reviewed: April 2026
Reviewed by , software engineer · last updated April 2026

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Input Code
Results

Results will appear here after you paste code.

Paste code above to count lines.

How to Use the Code Line Counter

To use the Code Line Counter, follow these steps:

1. Choose a language or leave it on Auto-detect to let the tool identify the comment syntax.

2. Paste your code into the input area.

3. The results will update instantly as you type, showing the total, code, comment, and blank line counts with percentage bars.

4. Download the report to save a plain-text summary for documentation.

When to Use the Tool in Real Workflows

Use the Code Line Counter when you need to quickly assess the size and complexity of your codebase. It's particularly useful for:

1. Project managers to estimate code complexity and size for planning.

2. Developers to evaluate documentation quality before code reviews.

3. Organizations to track lines of code (LOC) as a rough proxy for technical debt.

4. Single-file analysis in a browser without installing anything.

How It Works

The Code Line Counter works by analyzing the code you paste into the input area. It counts lines based on the following criteria:

1. Blank lines: Contain only whitespace characters or are completely empty.

2. Comment lines: Start with a comment delimiter or are inside an active block comment.

3. Code lines: Any non-blank, non-comment line. Supports multiple languages, including JavaScript, Python, CSS, HTML, Java, and C#. Can auto-detect the language from the comment syntax.

Tips, Edge Cases, or Limitations

Here are some tips and considerations when using the Code Line Counter:

1. The tool is 100% client-side, meaning your code is never sent to a server.

2. Multi-line block comments are tracked across lines using a state flag.

3. Lines that contain both code and an inline comment are counted as code lines, not comment lines.

4. The tool does not count lines inside multi-line strings.

5. LOC metrics should be interpreted carefully, as fewer, well-crafted lines often indicate higher quality than more verbose code.

Frequently Asked Questions

A code line is any non-blank, non-comment line. A comment line starts with a comment delimiter or is inside an active block comment.
The tool inspects the first 30 lines for tell-tale patterns to identify the language. It supports JavaScript, Python, CSS, HTML, Java, and C#.
No, the tool does not count lines inside multi-line strings.
There is no one-size-fits-all answer, but a good ratio of comments to code depends on the project and the team's coding standards.
No, the tool is 100% client-side, meaning your code is never sent to a server.