How to Count Days and Weeks Correctly
Inclusive dates, elapsed time, and ISO weeks: understand which convention your calculation uses.
Read articleDate and Time Calculators
Date and Time Calculators
Browse date and time calculators and related tools on Calculator 360.
What Week Is It
Find the ISO 8601 week number of an explicitly chosen date. ISO weeks begin on Monday, and their year can differ from the calendar year around New Year.
Days Until Calculator
Count days until a target from the local starting date you enter, or compare any two entered calendar dates. Past targets show a negative Days Until value.
Age Calculator
Calculate completed years, additional months, days, and total days from a birth date to the reference date you choose.
Time Duration Calculator
Find the duration between two times, including a crossing of midnight, or add up to 31 time spans with optional breaks.
Date Calculator
Add or subtract a whole number of calendar days. The result displays an English date and weekday.
Working Days Calculator
Choose the right calculator
Find ISO week numbers, date differences, ages, and time durations using the available date and time calculators.
What Week Is It
Find the ISO 8601 week number of an explicitly chosen date. ISO weeks begin on Monday, and their year can differ from the calendar year around New Year.
Days Until Calculator
Count days until a target from the local starting date you enter, or compare any two entered calendar dates. Past targets show a negative Days Until value.
Age Calculator
Calculate completed years, additional months, days, and total days from a birth date to the reference date you choose.
Time Duration Calculator
Find the duration between two times, including a crossing of midnight, or add up to 31 time spans with optional breaks.
Date Calculator
Add or subtract a whole number of calendar days. The result displays an English date and weekday.
Working Days Calculator
Frequently asked questions
Which tools are available?
Only the calculators listed on this page are available in English.
Do I need an account?
No. The available tools work without an account.