How we calculate time
These notes explain the methods, assumptions and limits of the time tools.
Life calendar
Years run from birthday to birthday. Weeks are consecutive seven-day blocks beginning at birth. The day view shows one age-year. A February 29 birthday uses February 28 in a non-leap year. Your selected reference age is illustrative; it is not a lifespan prediction.
Open life calendar →World clock
The browser calculates local times using Intl.DateTimeFormat and IANA time-zone names. Daylight saving changes depend on the time-zone rules on the device. Clock accuracy depends on the device clock.
Open world clock →Countdowns
Target dates are converted into a moment in time. The visible countdown updates while the page is open. Device time or time-zone changes can affect how a date appears. Personal countdown dates are entered in the device’s local time zone.
Create a countdown →Work, payday and retirement
These tools use dates and recurrence rules you enter. They do not verify labor law, holidays, payroll rules, or retirement eligibility.
Explore payday timer →For explanation only; not medical, labor, or financial advice.