How to use the common availability finder
- Enter the shortest window you want to find and choose a 12 or 24 hour clock.
- For each person type the weekly times they can meet, such as Mon-Fri 9:00-12:00, 13:00-17:00; Sat 10am-2pm.
- Add as many people as you need, up to ten.
- Read the windows everyone shares, the total shared time and the time each person offered.
Formula
merge each person's windows on each day when they overlap or touch
shared time on a day = the intersection of every person's windows on that day
keep windows that are at least as long as the shortest window you set
Days run Monday to Sunday and repeat every week. Times must be in the same time zone, and a window cannot cross midnight, so split it into two days.
Three people and a one hour meeting
Ana is free Monday to Friday 9:00-12:00 and 13:00-17:00. Ben is free Monday, Tuesday and Thursday 10:00-15:00, Wednesday 8:00-11:00 and Friday 13:00-18:00. Cy is free Monday to Thursday 11:30-14:30 and Friday 9:00-12:00.
On Monday Ana and Ben share 10:00-12:00 and 13:00-15:00, and adding Cy leaves 11:30-12:00 and 13:00-14:30. Only the second is at least 60 minutes, and the same holds on Tuesday and Thursday. There are 3 shared windows of 1 h 30 min, 4 h 30 min in total, all from 1:00 PM to 2:30 PM. With a 30 minute minimum the 11:30 slots appear too, and the count rises to 6. A 3 hour minimum finds none.
How times can be written
Days can be single (Mon), ranges (Mon-Fri), lists (Mon,Wed,Fri) or the words Weekdays, Weekends and Daily. Times can be 24 hour (13:30), whole hours (9-17) or with am or pm (9am-12:30pm). Separate groups with a semicolon or a new line, and separate several time ranges for the same days with commas. The tool names the person and the piece of text when it cannot read something.
Once you have a window, convert it for each person with the Time Zone Converter and check the current time in their cities with the World Clock. For ranges of dates instead of weekly times, the Date Overlap Calculator finds the days two ranges share.
What a shared window does not tell you
A window of 90 minutes can host a meeting of up to 90 minutes starting at its first minute, or later by any amount that still leaves the meeting inside the window. The tool does not know about holidays, one-off changes, travel time or daylight saving changes, so confirm the day you pick with everyone.
Assumptions and limits
- The same week repeats, and everyone's times are in one time zone.
- Windows that only touch, such as 9-10 and 10-11, count as one window of two hours.
- A window may end at midnight, written 24:00, but not cross it.
- The names and times stay out of share links, the calculation runs in your browser, and nothing is uploaded.
Frequently asked questions
What if people are in different time zones?
Convert each person's times into one common zone before you enter them. The tool compares the clock times as written and does not know where anyone lives.
Why does a window that looks long not appear?
It is probably shorter than the minimum you set, or one person is not free for all of it. Lower the minimum to see the shorter windows too.
Can I find only the best start time?
The table lists whole windows. For a meeting of a given length, the start can be anywhere from the start of the window to the end minus the length.
What does the offered time per person mean?
It is the total time each person listed in the week after overlaps are merged, shown so you can see who has the least flexibility.