Claude Counter

A minimal browser extension that shows token count, cache timer, and usage bars on claude.ai.

Features

• Token count — Approximate token count for the current conversation, with a mini progress bar against the 200k context limit
• Cache timer — Countdown showing how long the conversation remains cached (cheaper to continue)
• Usage bars — Session (5-hour) and weekly (7-day) usage from Claude's native API, with progress bars and reset countdowns (more accurate than the rounded /usage page)

Installation

Chrome / Edge / Chromium

1. Download claude-counter-0.4.2.zip
2. Go to chrome://extensions and enable Developer mode
3. Drag and drop the zip onto the page

Firefox

1. Download claude-counter-0.4.2.xpi
2. Drag it into any Firefox window and click Add

Userscript

1. Install the userscript from claude-counter.user.js

How it works

• Intercepts Claude's API responses to read conversation data and usage info
• Uses a vendored tokenizer (o200k_base) for approximate token counting
• Uses Claude’s /usage plus live SSE message_limit data; the SSE provides exact, unrounded utilization fractions, so the progress bars are more accurate than the rounded percentages shown on Claude’s native /usage page
• Watches for DOM changes to inject UI elements as you navigate

Privacy

• All data stays local — no external servers, no tracking
• Reads your lastActiveOrg cookie to query Claude's /usage endpoint
• Makes requests only to claude.ai

Credits

• Token counting via gpt-tokenizer (MIT)
• Inspired by Claude Usage Tracker by lugia19

License

MIT