When should you call?

Select a business or office, its support line and your time zone. Weekly hours include daylight-saving changes, but not holidays, exceptional closures or queues. Confirm unverified schedules with the official source.

India is 9 hours 30 minutes ahead of US Eastern in summer and 10 hours 30 in winter, and it never changes its own clocks, so the gap moves twice a year at the American end. In practice that puts the workable window in your morning: 8am in New York is early evening in Delhi, which is a reasonable hour for a family call and the wrong end of the day for an office. Set both ends above and the tool does this for whichever two places you actually need.

Because the gap between two places is not a constant. The two ends change their clocks on different dates, and several countries do not change at all. The tool checks current offsets for both places.

Personal-call mode uses 9am to 8pm in the recipient's time zone. Being conservative costs you an hour at each end. Being generous costs somebody a call at seven in the morning.

No account is needed to compare times or download a calendar window. Calling opens Airlophone's sign-in and keypad flow. Your own time zone comes from your browser's own setting rather than from your IP address, so the page never has to ask where you are.