Date & Time
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All 36 Date & Time Tools
Age Calculator
Exact age, days lived and birthday countdownDate Difference Calculator
Days, months and years between two datesDate Calculator
Add or subtract days and workdays from a dateEbbinghaus Review Planner
Forgetting-curve review dates at 1/2/4/7/15/30 daysCountdown Timer
Days, hours, minutes and seconds to a target dateWorkday Calculator
Number of workdays between two datesTime Zone Converter
Current time across major world citiesWeekday Calculator
Day of the week for any dateHoliday Countdown
Countdown to major Chinese festivalsChinese Lunar Calendar Converter
Gregorian to lunar date with Ganzhi yearNEWSolar Terms Calendar
24 solar terms with exact datesNEWChinese Zodiac Calculator
Zodiac animal by birth yearWeek Number Calculator
ISO week, day of year and year progressTime Calculator
Add/subtract durations and find time differencesZodiac Sign Calculator
Birth date to star sign with dates and elementsDays Alive Calculator
Days lived plus your 10,000-day milestonesRetirement Age Calculator
China 2025 delayed-retirement schedule and dateAnnual Leave Calculator
Statutory leave by tenure, proration and compensationWork Years Calculator
Tenure in years/months/days and annual leave tierHours Calculator
Duration between times, overnight shifts, breaksLeap Year Checker
4/100/400 rules, nearby leap yearsMoon Phase Calculator
Lunar age, illumination, next full/new moonExam Countdown
Gaokao/postgrad exam days remainingSanfu (Dog Days) Calculator
Dog days & Shujiu dates, Geng-day algorithmSunrise Sunset Calculator
9 cities, day/night lengthBaby 100 Days Calculator
Full month, 100 days, milestonesSchool Age Calculator
Aug 31 cutoff, full education timelineBusiness Days Calculator
Count or add working daysAnniversary Calculator
Day/year milestones timelineLunar Birthday Calculator
Lunar to solar · next 10 yearsShichen (Chinese Hours)
Time to shichen · aliases & zodiacTime Add & Subtract
Sum multiple durations · timecodes & splits · averageTime Multiplier
Duration × multiplier · playback speed time · binge totalsShelf Life Calculator
Expiry date · days remaining · expiring/expired checkChinese Almanac
Lunar date · ganzhi cycle · zodiac · solar terms · festivalsChina Public Holidays 2026
Statutory holidays · makeup workdays · countdownRelated Guides
Date Difference: Days Between Dates & Date Arithmetic
Days between dates: count end − start; 2025-01-15 to 2025-03-20 = 64 days. Inclusive counting adds 1. Month lengths vary (28-31) and Feb jumps on leap years — the two traps. Includes the 30/360 banking convention and week/day breakdowns.
Age Calculation: Full Age (周岁) vs Nominal Age (虚岁)
Full age (周岁): completed years since birth — birthday passes, +1. Nominal age (虚岁): 1 at birth, +1 every Lunar New Year — typically 1-2 years higher than full age. Includes exact age-to-the-day math, legal age rules and zodiac-year pitfalls.
Retirement Age: The Delayed Retirement Schedule Explained
China's delayed retirement (from 2025): men 60 → 63 over 15 years (+1 month per 4 months); women cadres 55 → 58 (+1 per 4 months); women workers 50 → 55 (+1 per 2 months). Born later = retire later. Includes the lookup method, flexible early/late options and pension math.
Time Conversion: Hours, Minutes, Seconds, Days & Weeks
1 day = 24 h = 1,440 min = 86,400 s; 1 week = 168 h; 1 year ≈ 8,760 h (8,784 leap). Decimal hours: 1.5 h = 1 h 30 min — 0.1 h = 6 min, not 10. Includes work-hour math, timesheet decimals and the million/billion-seconds milestones.
Countdown Calculation: Days Until Any Date
Days until = target date − today. Countdowns exclude today, include the target (or not — define it). 100-day milestones, workday-only countdowns, and the psychology of deadline math. Includes formulas for weeks+days display and repeated-event countdowns.
Workday Calculation: Business Days Excluding Weekends & Holidays
Workdays = total days − weekend days − holidays (+ makeup workdays). A 30-day span has ~22 workdays. China's twist: 调休 makeup weekends where Saturdays become workdays. Includes the counting algorithm, deadline math and project-schedule pitfalls.