A fuel gauge for your Claude conversations

What it does

Claude Counter is a browser extension that overlays three pieces of telemetry onto claude.ai: a running token count with a progress bar against the 200k context window, a countdown timer for how long your conversation stays cached (cheaper to resume), and granular session/weekly usage bars drawn from Claude’s own API. It ships as a Chrome/Edge extension, Firefox add-on, or plain userscript.

The interesting bit

The extension doesn’t just scrape the rounded percentages from Claude’s /usage page. It intercepts live SSE message_limit data and queries the native API directly, yielding unrounded utilization fractions. The README notes this produces “more accurate than the rounded /usage page” progress bars — a small but satisfying correction of a UI white lie.

Key highlights

• Approximate token counting via a vendored o200k_base tokenizer (from gpt-tokenizer)
• Cache timer shows remaining cheap-window time, so you know when continuing a thread gets pricier
• Session (5-hour) and weekly (7-day) usage bars with reset countdowns
• All data stays local; no external servers, only requests to claude.ai
• Also available as a userscript for the extension-averse

Caveats

• Token counts are explicitly approximate; the README doesn’t claim exactness
• Requires reading your lastActiveOrg cookie to hit the usage endpoint
• Intercepts API responses and watches DOM mutations, which is standard for this class of extension but worth knowing

Verdict

Heavy Claude users who hit limits or obsess over context windows will find this genuinely useful. Casual users who never check /usage can skip it.