Tools
Free, fast calendar tools.
All tools run in your browser — no sign-up, no tracking of inputs, no data ever sent to a server.
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Week Number Calculator
ISO week number for today or any date you pick.
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Days Between Dates
Difference in days, weeks, months, business days.
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Date Calculator
Add or subtract days, weeks, months, or years.
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Age Calculator
Exact age in years, months, days, hours.
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Countdown Timer
Live countdown to Christmas, New Year, and custom dates.
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Why these tools?
Spreadsheets and operating system date pickers can answer most of these questions, but they're slow when you just need a quick number. These tools give you the answer in one keystroke and stay accurate for ISO weeks, leap years, and business-day counts.
Privacy
Every calculation happens in your browser using JavaScript. The dates you enter never leave your device.