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Use this shelf when a date, duration, age, or elapsed-time answer needs to be clear without hand-counting a calendar.
Count days, calculate exact age, and work out elapsed time without saving anything or building a spreadsheet.
Educational date and time estimates only — values stay in the browser and are not saved or sent.
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These are the calculators people are most likely to need first.
Use this shelf when a date, duration, age, or elapsed-time answer needs to be clear without hand-counting a calendar.
Use date difference for two calendar dates, time duration for hours and minutes, and age when the question is birthdate-based.
Check time zone, daylight saving time, inclusive counting, business days, holidays, payroll rules, and the official deadline source.
Suggested workflow: For deadlines, calculate the plain answer first, then rerun it using the official rule for inclusive days, business days, or local time.
Count days, weeks, approximate months, and approximate years between two dates.
Calculate age in years, months, days, total days, and total weeks.
Calculate elapsed hours and minutes between start and end times, including overnight spans.