A lightweight browser extension that shows token count, cache timer, usage bars, live 80% usage warnings, and a real-time "last updated" timestamp on claude.ai — all in one clean row.
- 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)
- ⚠ Usage warning — A warning banner appears inline when either your session or weekly usage hits 80%, so you're never caught off guard before hitting the limit
- Last updated — A live "updated X ago" timestamp so you always know how fresh the data is (e.g. "just now", "3m ago", "1h ago")
- Download claude-usage-tracker.zip
- Go to
chrome://extensionsand enable Developer mode - Drag and drop the zip onto the page
- Download claude-usage-tracker.xpi
- Drag it into any Firefox window and click Add
- Install the userscript manager (e.g. Tampermonkey)
- Install from
userscript/claude-counter.user.js
- 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
/usageplus live SSEmessage_limitdata; 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
- The 80% warning banner and "last updated" timestamp are computed entirely client-side with no extra requests
- All data stays local — no external servers, no tracking
- Reads your
lastActiveOrgcookie to query Claude's/usageendpoint - Makes requests only to
claude.ai
- Token counting via gpt-tokenizer (MIT)
- Inspired by the original Claude Usage Extension by lugia19
MIT — see LICENSE