4/10 zones
Find the hour that works everywhere
Add the places you work with, tap an hour of your day, and share the link. Working hours are the light cells, night is dark, and every midnight is marked.
How it works
The first row is your home place and shows one day, midnight to midnight; every other row shows what its own clock reads in the same column. Tap a column to move the red frame, or use the arrow keys: an hour at a time, a quarter hour with Shift, a day with Page Up and Page Down, and Home returns to now. Pick another day in the strip above the board and the readouts on the left follow. A column that is light all the way down is a meeting time everyone can live with. On a daylight-saving day a row has 23 or 25 columns and the shift is marked where it happens. The URL describes exactly what you see, so a copied link opens the same view for anyone.
Everything runs in your browser using its built-in time zone database, and your zones and times never leave it. Page views and clicks are counted anonymously with Google Analytics to improve the tool, with no ads and no cross-site tracking; the About page has the details.