diff --git a/scripts/source_stats.py b/scripts/source_stats.py
new file mode 100755
index 000000000000..9b0093a937ba
--- /dev/null
+++ b/scripts/source_stats.py
@@ -0,0 +1,164 @@
+#!/usr/bin/env python3
+
+"""Script to compute statistics about source code."""
+
+from __future__ import annotations
+
+__copyright__ = """
+Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+Exceptions. See /LICENSE for license information.
+SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+"""
+
+import argparse
+from alive_progress import alive_bar  # type:ignore
+from multiprocessing import Pool
+import re
+import termplotlib as tpl  # type:ignore
+from pathlib import Path
+from typing import Dict, List, Optional
+from dataclasses import dataclass, field, asdict
+from collections import Counter
+
+BLANK_RE = re.compile(r"\s*")
+COMMENT_RE = re.compile(r"\s*///*\s*")
+LINE_RE = re.compile(
+    r"""
+    (?P<class_intro>\b(class|struct)\s+(?P<class_name>\w+)\b)|
+    (?P<end_open_curly>{\s*(?P<open_curly_trailing_comment>//.*)?)|
+    (?P<trailing_comment>//.*)|
+    (?P<id>\b\w+\b)
+""",
+    re.X,
+)
+
+
+@dataclass
+class Stats:
+    """Stats collected while scanning source files"""
+
+    lines: int = 0
+    blank_lines: int = 0
+    comment_lines: int = 0
+    empty_comment_lines: int = 0
+    comment_line_widths: Counter[int] = field(default_factory=lambda: Counter())
+    lines_with_trailing_comments: int = 0
+    classes: int = 0
+    identifiers: int = 0
+    identifier_widths: Counter[int] = field(default_factory=lambda: Counter())
+    ids_per_line: Counter[int] = field(default_factory=lambda: Counter())
+
+    def accumulate(self, other: Stats) -> None:
+        self.lines += other.lines
+        self.blank_lines += other.blank_lines
+        self.empty_comment_lines += other.empty_comment_lines
+        self.comment_lines += other.comment_lines
+        self.comment_line_widths.update(other.comment_line_widths)
+        self.lines_with_trailing_comments += other.lines_with_trailing_comments
+        self.classes += other.classes
+        self.identifiers += other.identifiers
+        self.identifier_widths.update(other.identifier_widths)
+        self.ids_per_line.update(other.ids_per_line)
+
+
+def scan_file(file: Path) -> Stats:
+    """Scans the provided file and accumulates stats."""
+    stats = Stats()
+    for line in file.open():
+        # Strip off the line endings.
+        line = line.rstrip("\r\n")
+        # Skip over super long lines that are often URLs or structured data that
+        # doesn't match "normal" source code patterns.
+        if len(line) > 80:
+            continue
+        stats.lines += 1
+        if re.fullmatch(BLANK_RE, line):
+            stats.blank_lines += 1
+            continue
+        if m := re.match(COMMENT_RE, line):
+            stats.comment_lines += 1
+            if m.end() == len(line):
+                stats.empty_comment_lines += 1
+            else:
+                stats.comment_line_widths[len(line)] += 1
+            continue
+        line_identifiers = 0
+        for m in re.finditer(LINE_RE, line):
+            if m.group("trailing_comment"):
+                stats.lines_with_trailing_comments += 1
+                break
+            if m.group("class_intro"):
+                stats.classes += 1
+                line_identifiers += 1
+                stats.identifier_widths[len(m.group("class_name"))] += 1
+            elif m.group("end_open_curly"):
+                pass
+            else:
+                assert m.group("id"), "Line is '%s', and match is '%s'" % (
+                    line,
+                    line[m.start() : m.end()],
+                )
+                line_identifiers += 1
+                stats.identifier_widths[len(m.group("id"))] += 1
+        stats.identifiers += line_identifiers
+        stats.ids_per_line[line_identifiers] += 1
+    return stats
+
+
+def parse_args(args: Optional[List[str]] = None) -> argparse.Namespace:
+    """Parsers command-line arguments and flags."""
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument(
+        "files",
+        metavar="FILE",
+        type=Path,
+        nargs="+",
+        help="A file to scan while collecting statistics.",
+    )
+    return parser.parse_args(args=args)
+
+
+def main() -> None:
+    parsed_args = parse_args()
+    stats = Stats()
+    with alive_bar(len(parsed_args.files)) as bar:
+        with Pool() as p:
+            for file_stats in p.imap_unordered(scan_file, parsed_args.files):
+                stats.accumulate(file_stats)
+                bar()
+
+    print(
+        """
+## Stats ##
+Lines: %(lines)d
+Blank lines: %(blank_lines)d
+Comment lines: %(comment_lines)d
+Empty comment lines: %(empty_comment_lines)d
+Lines with trailing comments: %(lines_with_trailing_comments)d
+Classes: %(classes)d
+IDs: %(identifiers)d"""
+        % asdict(stats)
+    )
+
+    def print_histogram(
+        title: str, data: Dict[int, int], column_format: str
+    ) -> None:
+        print()
+        print(title)
+        key_min = min(data.keys())
+        key_max = max(data.keys()) + 1
+        values = [data.get(k, 0) for k in range(key_min, key_max)]
+        keys = [column_format % k for k in range(key_min, key_max)]
+        fig = tpl.figure()
+        fig.barh(values, keys)
+        fig.show()
+
+    print_histogram(
+        "## Comment line widths ##", stats.comment_line_widths, "%d columns"
+    )
+    print_histogram("## ID widths ##", stats.identifier_widths, "%d characters")
+    print_histogram("## IDs per line ##", stats.ids_per_line, "%d ids")
+
+
+if __name__ == "__main__":
+    main()