Time zone converter
Convert a date and time between cities, with daylight-saving changes and clear day differences.
Your inputs
Results update as you edit.
Calculations run in your browser. Inputs are not saved or sent to analytics.
How it works
- UTC instant = − UTC offset
- Destination time = UTC instant + UTC offset
- Worked example: Convert 18:00 in Tokyo on 2026-01-15 to UTC. Tokyo’s offset on that date is nine hours ahead. For locations with daylight-saving changes, use the offset for the chosen date rather than a permanent hour difference.
- 2026-01-15 18:00 (Asia/Tokyo) − 09:00 = 2026-01-15 09:00 UTC.
Input and formula key
Your result
Complete the inputs to see your result.
Your browser has outdated rules for a selected time zone. Update your browser and operating system; verify important dates against current local rules.
Assumptions and limitations
Time zone rules come from your browser and can lag legal changes. Future dates are predictions under those rules. City names and mappings use a reviewed GeoNames subset (CC BY 4.0); no location detection or saving. Dates before 1970 have limited historical reliability.
Sources
- IANA — time zone database and accuracy Sources reviewed: 2026-10-07
- GeoNames — city data, CC BY 4.0 (curated and modified) Sources reviewed: 2026-10-07
- Creative Commons — Attribution 4.0 license Sources reviewed: 2026-10-07
