Web向けユーティリティ時計
クラシックなオンライン時計にインスパイアされたダークファーストのツール：音と通知付きアラーム、タイマー、世界時刻。高速でクロールしやすいURL。
午前06:04:37
2026年11月10日火曜日
Local System Time
Utility Suites & Categories
Select a suite to open full-featured online calculators, timers, and timing utilities.
アラーム
Reliable browser alarms with recurring options, multiple schedules, and Web Audio API synthesizer fallbacks.
タイマー
Custom and preset countdowns with visual progress rings, fullscreen mode, and audible notifications.
ストップウォッチ
Precision millisecond stopwatch tracking with split times, fastest/slowest lap highlighting, and lap export.
世界時計
Live local times across global cities with automatic Daylight Saving Time handling and multi-city overlap planner.
日付とカレンダー
Exact biological age calculator, working business days counter, date differences, and leap year checks.
電卓・計算機
Instant percentage calculators, metric-imperial scientific unit converter, and keyboard-accessible basic calculator.
生産性ツール
Ultradian sleep cycle planner, Pomodoro focus sprints, customizable interval HIIT timers, and event countdowns.
単位換算ツール
Scientific unit conversions across area, volume, pressure, energy, power, fuel economy, and cooking measurements.
金融・財務計算機
Financial loan EMI calculator, compound growth modeling, GST/VAT invoices, profit margins, and savings goals.
テキストツール
Client-side text tools: word & character counting, case conversions, duplicate line removal, and diff comparison.
Popular Utility Tools & Shortcuts
Engineered for Accuracy, Privacy & Offline Utility
UtilityClock is built from the ground up without third-party tracking, heavy analytics scripts, or remote calculation servers. Everything computes locally on your device.
100% Client-Side Privacy
Your alarm times, dates of birth, stopwatch laps, and calculator inputs never leave your device. No accounts, cookies, or remote logging.
Offline PWA Capable
Equipped with a modern Progressive Web App Service Worker that precaches core tools and audio chimes so you can keep working even when disconnected.
Microsecond Native Precision
Timers rely on high-resolution performance.now() and Web Audio synthesis rather than drifted interval loops.