Date and Calendar Tools

Days

• Add Days to Date

  Add calendar days to a date with option to include the start date in the calculation.

• Days Between Dates Calculator

  Calculate the number of days between two dates with options to include or exclude the start and end dates.

• How Many Days Until a Date

  Day Calculator: from today to any future date.

• Subtract Days from Date

  Subtract calendar days from a date with the option to include or exclude the start date.

• Convert Days to Weeks

  Days to weeks converter with remaining days.

• Convert Days to Months

  Days to months converter with customizable month length. Calculates full months and remaining days.

Working days

• Add Business Days to Date

  The calculator adds business days to a date, skipping weekends and holidays. Shows the completion and delivery date.

• Working Days Calculator Between Dates

  Shows the number of working days between two dates, accounting for weekends and holidays.

• Subtract Working Days from Date

  Calculator subtracts working days from a date, skipping weekends and holidays.

Weeks

• Weeks Between Dates Calculator

  Calculate full weeks and remaining days between two dates.

• Add Weeks to Date

  Add full weeks to any date and find the resulting date with the day of the week.

• Subtract Weeks from Date

  Subtract a specified number of full weeks from any date.

• Convert Weeks to Days

  Weeks to days converter, accepts whole and fractional week values.

Calendar

• Calendar for Any Year

  Calendar with year navigation and week start selection.

• Shift Calendar

  This tool is designed for visualizing work schedules. It generates a calendar grid based on a specified shift cycle and start date.

• Working Days and Days Off Calendar

  Displaying the schedule for the selected year, dividing dates into working days, weekends, and public holidays.

• Day Number in Year by Date

  This tool determines the ordinal day number in a year for any selected date. Specify the day, month, and year to calculate the number from 1 to 366.

• Date by Day of Year

  This tool converts the ordinal day number to a calendar date (day, month, and day of the week) based on the number and specified year.

• Week Number by Date

  Shows the week number for any date using ISO 8601 (international) or US (traditional, from January 1) standards.

• Full Weeks in a Year Calculator

  Calculates how many full weeks fit in a specified year with a selectable first day of the week.

Age

• Age Calculator

  Calculate your age from your date of birth to the current or any other date.

• Age Difference Calculator

  Tool for calculating age difference by birth dates. Results in years, months, and days, plus the total number of days between birth dates.

• Find Your Birth Day of the Week

  This tool shows the day of the week for a specified birth date.

Time & date

• Add Time to Date and Time

  Add any number of hours and minutes to a starting date and time.

• Subtract Time from Date and Time

  Subtract hours and minutes from a starting date and time.

• Time Between Dates Calculator

  Calculate time difference: from minutes to days between two dates.

Months

• Add Months to Date

  Adds a specified number of months to a date with a choice of calculation method: calendar or mathematical.

• Subtract Months from Date

  Subtracts a specified number of months from a date with a choice of calculation method: calendar or mathematical.

• Months Between Dates Calculator

  Calculate calendar months and remaining days between dates.

• Convert Months to Days

  Months to days converter with customizable month length.

Years

• Years Between Dates Calculator

  Shows how many years between two dates and the remainder in months and days according to the calendar.

• How Many Years Have Passed Since a Year

  Calculate the number of years from a specified year to today with support for BCE dates.

Useful resources

• Date Calculator Structure and Calculation Methods

  A breakdown of date calculators: how algorithms convert calendar to numbers, account for leap years, and calculate the difference between dates.

• How to Calculate a Project Deadline

  Step-by-step project deadline calculation: from task breakdown to final date assembly with risk considerations.

• How to Calculate the Day of the Week for Any Date Mentally

  Learn to determine the day of the week for any date without a calendar! We break down John Conway's algorithm.

• ISO 8601 – The Global Standard for Dates and Time

  Learn what the ISO 8601 standard is, how it solves the problem of different date formats worldwide, and why it's important for global web services.