Time Difference Calculator
Compare live clocks for two to five cities side by side, see every pairwise time difference, and find the shared 09:00–17:00 working-hours window for calls.
Pick at least two cities from the suggestions to compare their clocks.
Formula: Zones come from coordinates via an offline IANA database; offsets and DST are computed for the current date, so differences already reflect daylight saving where observed.
How to use this tool
Type two or more cities and pick each from the suggestions.
Watch the live clocks tick side by side.
Read the pairwise differences and the shared working-hours window.
What people use this tool for
New York vs London vs Tokyo — who is awake right now?
Finding a meeting slot that works in San Francisco, Berlin and Singapore
How it's calculated
Each city is geocoded, its coordinates matched to an IANA zone via an offline database, and offsets computed for the current date with the browser's Intl engine (daylight saving included). The working-hours overlap is found by scanning each zone's 09:00–17:00 window converted to UTC and intersecting them; a window under 30 minutes is reported as none.
Related tools and resources
Frequently asked questions
How many cities can I compare?
Two to five. Add more with the + button; remove with the × button (minimum two).
Does it handle daylight saving?
Yes — offsets are computed for today's date, so DST differences between hemispheres are reflected.
What is the working-hours overlap?
The UTC window where all cities are simultaneously within 09:00–17:00 local time — the practical slot for a call.
Why is there sometimes no overlap?
With cities spread across many zones (e.g. Los Angeles and Sydney) the workdays may not intersect at all.
Are the clocks live?
Yes, they tick every second from your device clock converted into each zone.
What if my city is not found?
Try a larger nearby city or the full 'City, Country' form in the search box.
Is my search data stored?
No — geocoding runs per keystroke and nothing is saved.
Why do some differences include 30 minutes?
A few zones use half-hour or 45-minute offsets (e.g. India, Nepal, parts of Australia).