Online Time Tracker od thedoctor

Time Tracker automatically monitors your browsing activity and shows exactly how long you spend on each website. View your usage through an interactive calendar with daily totals, detailed bar charts (by hour, week, month, year or all time) and per-site history with averages. A live badge on the toolbar shows your current session at a glance.

Features:

Automatic, passive time tracking: no manual input needed
Calendar view with color-coded daily totals
Interactive charts with daily, weekly, monthly, yearly and all-time ranges
Per-site detail pages with visit history and daily averages
Hourly breakdown for any given day
Toolbar badge showing live time on the active site
Auto-pauses when idle or window loses focus
Export & import your data as JSON
Delete individual entries, sites or all data
Available in 9 languages (English, Türkçe, Español, 中文, Français, Русский, Deutsch, 日本語, Italiano)
Expand to a full-page view for a larger dashboard
Works on Firefox Desktop and Android

No data collection, everything stays in your browser