Estimate time zone from longitude

Estimate the theoretical solar time offset (UTC+/-) for a GPS longitude, assuming that each 15° slice of longitude corresponds to one hour of offset.

Example:
Estimated solar offset

UTC+0:09 (0.16 h)

How it works

The Earth completes a full rotation (360°) in 24 hours, which is 15° of longitude per hour. This tool applies that simple rule to estimate the "natural" solar time offset of a place: longitude divided by 15.

Is this the legal time zone of that place?

No — and this matters. Legal time zones follow political and administrative boundaries, not pure longitude: an entire country can adopt a single time zone even if it spans several 15° slices, and some territories use half-hour or quarter-hour offsets (India, Nepal, some Pacific islands). This estimate gives only the theoretical solar time, useful in astronomy or navigation, but it does not replace an official time zone database.

100% local processing: the calculation runs entirely in your browser — no data is sent to a server.