Format YYYY-MM-DD. Use the button below to fill in today.
Format HH:MM, for example 14:30.
It does not know anyone’s actual schedule. A green tag means the hour is plausible, not that the person is free. Public holidays are not included.
Calculated entirely in your browser. Nothing you enter is sent anywhere.
How to use it
Set the date and time
In your own time zone. Today's date and the current time are filled in for you.
Add up to three participants
Choose each person's zone from the list. Leave any unused.
Read the flags
Green means between 8am and 7pm for them. A cross means it is not.
How the calculation works
The tool converts one instant in time into local wall-clock time for every zone you add, using the time zone database built into your own browser. That is the same data your operating system uses, so daylight saving transitions are handled automatically.
This matters more than people expect. The gap between New York and London is five hours for most of the year but four for roughly two weeks in March and one in October, because the two regions change clocks on different dates. A fixed offset calculation gets those weeks wrong.
Working hours are marked as 8am to 7pm local, deliberately wider than a standard workday. The point is to flag the meetings that are genuinely unreasonable rather than every meeting slightly outside nine to five.
What this calculator does not do
It does not know anyone's actual schedule, holidays or preferences. A green flag means the hour is plausible, not that the person is free.
Public holidays are not included. A meeting at 10am on a national holiday still shows as working hours.
It does not create a calendar invite. Copy the times into whatever calendar you already use.
Questions
Does it handle daylight saving?
Yes. It uses your browser's time zone database, so each zone changes on its own schedule automatically.
Why is my city not listed?
The list covers the major zones. Pick the nearest city in the same zone — the offset is identical.
What counts as working hours?
8am to 7pm local. That is wider than a standard workday on purpose, so the warning means something.
Is anything sent to a server?
No. The conversion happens in your browser using data already on your device.
Related calculators
Reading Time Calculator
Words, characters and reading time.
LIVEProject Hours Estimator
Quote with PERT weighting.
LIVEFreelance Day Rate
Work out your minimum day rate.
LIVESomething wrong with this calculator? Report it and it gets fixed or taken down.
