Date Calculator

• Date Interval: Calculate days, weeks, months and years between two dates

• Date Arithmetic: Add or subtract days, weeks, months, years from a specified date

• Age Calculation: Calculate precise age and birthday information based on birth date

• Workdays Calculation: Calculate workdays between two dates (option to include weekends)

• Weekday Query: Query what day of the week a specific date is, plus day/week of year info

• Leap Year Rules: Years divisible by 4 but not by 100, or divisible by 400

• Workdays: Usually Monday to Friday, excluding weekends and holidays

• Quarter Division: Q1(Jan-Mar), Q2(Apr-Jun), Q3(Jul-Sep), Q4(Oct-Dec)

• ISO Week: International standard week starts Monday, first week contains January 4th

• Timezone: This calculator uses local timezone for calculations