Date & Time Calculators
Age Calculator
Find your age in completed years and total elapsed days between two dates.
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Date & Time Calculators
Compare calendar dates, calculate completed age, and count elapsed or remaining days with explicit date rules.
Date & Time Calculators
Date Difference Calculator
Count the exact number of elapsed days between two calendar dates.
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Days Until Calculator
Count down the number of days from a starting date to a target date.
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Use the age calculator for completed calendar years, the date difference calculator for elapsed days between two dates, and the days-until calculator for a countdown from today or another starting date. The tools compare calendar dates rather than clock times.
- Completed age changes only after the birthday has occurred in the reference year.
- Elapsed-day results use calendar dates and UTC day boundaries to avoid daylight-saving shifts.
- Date Difference returns an absolute count; Days Until preserves the positive or negative direction.
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Worked decisions, assumptions, and checks that put the tools in context. Guides are currently published in English.
Calendar Days, Inclusive Counts & Completed Age: Avoid Off-by-One Errors
Choose between elapsed days, inclusive calendar dates, signed countdowns, and completed age with leap-year examples and clearly defined calendar rules.
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