Your time vs anywhere. Find a slot nobody hates.
Puts your time and any other cities side by side, so you can drag across the day and see instantly what a given hour looks like for everybody. It flags which hours are civil to propose and which ones land in someone's night, which is the actual question when you are scheduling across continents.
"They are two hours ahead" is only true until one of you changes the clocks. Daylight saving starts and ends on different dates in different countries — the EU and the US are out of step for a couple of weeks each spring and autumn — and large parts of the world, including most of Asia and Africa, do not observe it at all. Australia is split internally. So a fixed offset you memorised in January quietly becomes wrong in March, which is how recurring meetings drift.
Write the time zone into every invite, and use the city name rather than an abbreviation — CST means two different things depending on the continent. For anything recurring, agree the anchor zone once so it is clear whose clock the meeting follows when the changeovers hit. If one side always takes the bad hour, rotate it.
Your selected cities are kept in your own browser so they are still there next time. Nothing is sent to a server.