Lines of Code Counter

How to use

1. 1Paste source code into the existing sample block, click Add block for an empty one, or drop one or more files anywhere in the drop zone.
2. 2Pick a language for each block from the dropdown. Files dropped onto the page have their language detected from the file extension automatically.
3. 3Read per-block stats on the right of each block: total lines, source lines (SLOC), comment-only lines, blank lines, longest line, and size.
4. 4Scroll to the Aggregate card for the project totals and the By language table for a per-language summary.
5. 5Click Copy summary for a plain-text recap or Copy CSV to drop a row-per-block table into a spreadsheet.

About this tool

Lines of Code Counter scans one or many source files and reports total lines, source lines (SLOC), comment-only lines, blank lines, lines with trailing comments, line-comment lines, block-comment lines, longest line length, character count, and UTF-8 byte size, all from inside your browser. Each block is classified by language and tokenized with a per-language state machine that walks the input character by character, tracking whether the cursor is inside ordinary code, a string literal, a line comment, or a block comment, so a comment-like sequence inside a string never counts as a comment and a stray quote inside a comment never confuses the scanner. Coverage includes the C family (C, C++, Java, C#, Go, Rust, Kotlin, Swift, Scala, PHP), JavaScript and TypeScript with JSX and TSX (including template literals and ${} interpolations), CSS, SCSS, and Less, HTML, XML, and SVG with HTML-style block comments, JSON, JSON5, JSONC, YAML, TOML, SQL with single-line and block syntax, the scripting family (Python, Ruby, Perl, Shell, Lua, R, Elixir, Haskell), Markdown, and plain text. Shebang lines on Unix-style scripts are treated as comment lines so a Python or Bash file that opens with a hashbang lands in the right bucket. Drop multiple files onto the page and each one is read with the FileReader API, language is detected from the file extension (over forty extensions are mapped), and a per-block panel shows the breakdown alongside a sortable language totals table. The aggregate panel shows SLOC and comment percentages, blank-line percentages, the longest line across the entire project, and the total UTF-8 byte size, which is useful for code review, refactor planning, pull-request triage, school assignment stats, freelance time estimation, and weekly review reports. Copy a plain-text summary for a code review note or copy a CSV with one row per file plus a totals row to drop straight into a spreadsheet. Everything runs locally in your browser; the code and files you drop here are never uploaded to a server.

Free to use. Works in your browser. No signup, no login.