Date & time
Open Date & time on Happytails.ai. This view has the same page content and links, with explicit tool capabilities. Read the processing notes before using a tool.
Page guide
Find the right tool and get straight to your task.
No account needed.Age calculator
Work out completed years and total days between two dates.
Time calculator
Add up durations and see the total in hours and seconds.
Time zone converter
See what the same date and time means in another time zone.
Time card calculator
Work out hours and pay after taking out unpaid breaks.
Timer
Set a countdown in seconds.
Time duration
Work out the hours between two times, with breaks taken out.
Pomodoro timer
One focus session. Then a proper break.
Stopwatch
Measure elapsed time and take lap readings.
Business days
Count weekdays between dates, leaving out the holidays you enter.
Add days
Find the date a set number of days before or after another date.
Date difference
Find out how much time separates two dates.
Day of the week calculator
Find which weekday a date falls on.
Week number calculator
Find a date's ISO week number and week-year.
Habit tracker
Count daily, weekly or monthly habit streaks from your check-ins, with completion rates and every missed period listed.
Jet lag schedule planner
Compare your usual sleep window on the home and destination clocks, shifted step by step at a rate you choose. Add each planned night to your calendar.
Meeting availability poll builder
Make a one-page availability poll that shows each time slot in the organizer's zone, extra zones and each viewer's own time. People send back a short code, and you paste the codes here to count the answers.
Multi-city meeting planner
Find the hours when working days in several cities overlap. Each day lists the shared window in every city's local time and flags days near a clock change.
Road trip itinerary planner
Split a road trip into driving days using your own daily driving limit and break rule. See each drive, break and overnight stop, and add the plan to your calendar.
Time blocking planner
Plan a day by fitting your tasks into the time left around fixed commitments. Higher priority tasks go first, and anything that does not fit is listed.
Trip day-by-day calendar builder
Turn itinerary rows into a day-by-day trip plan and a calendar file. Each row keeps its own time zone, and rows without times become all-day entries.
About date & time
These free date and time calculators answer the questions that come up at work, at school and when planning. The Age calculator, Date difference and Business days tools count the time between dates, while Add days finds a deadline. The Time calculator and Time duration add or subtract hours and minutes, the Time card calculator totals a work week, and the Time zone converter lines up meetings across cities.
For counting work days, use Business days rather than Date difference, because it leaves out weekend days. For tracking time live, pick the Timer, Stopwatch or Pomodoro timer and keep the tab open while it runs.
Popular date & time
Common questions
Does the time zone converter handle daylight saving time?
Yes. The Time zone converter uses standard time zone data that includes daylight saving rules, so a chosen date shows the correct offset. Pick the exact date of your meeting, since offsets can change between seasons.
Will the timer keep running if I switch tabs?
Keep the tab open. Browsers can slow pages in background tabs, and a sleeping device may delay alerts. The Timer and Stopwatch track elapsed time against the clock, but closing the tab resets them.
How does the age calculator count months and days?
The Age calculator counts full years first, then full months, then the remaining days between the birth date and the date you choose. It accounts for month lengths and leap years, so results match what you would count on a calendar.