Time Zone Calculator
Written by Thierno Sadou Diallo, formula verified per our methodology • Last checked on 9/6/2026
To convert a time between two time zones, add the difference between their UTC offsets to the starting time. At 2:00 PM in Paris (UTC+1, winter time), it's 10:00 PM the same day in Tokyo (UTC+9).
Explanation
This calculator converts a time from one place to another based on their respective offsets from Coordinated Universal Time (UTC), the international reference. It adds the difference between the two offsets to the starting time, and indicates whether the result falls on the same day, the day before, or the day after — a large time difference between two distant places frequently pushes the result onto a different calendar day. An important point about this tool's scope: it converts between two UTC offsets that you provide yourself; it doesn't automatically know each country's daylight saving time rules (which change dates from year to year and region to region, and which some countries don't apply at all). You therefore need to enter the UTC offset actually in effect at the place and date you're interested in — for example UTC+1 for France in winter, UTC+2 in summer. To calculate your exact age rather than a time difference, see our age calculator.
Example: 2:00 PM in Paris (UTC+1) to Tokyo (UTC+9)
Inputs
Starting time: 2:00 PM. Source offset: UTC+1 (Paris, winter). Target offset: UTC+9 (Tokyo).
Calculation
Offset difference = 9 − 1 = 8 hours. 2:00 PM + 8h = 10:00 PM, the same calendar day.
Result
When it's 2:00 PM in Paris, it's 10:00 PM the same day in Tokyo.
Frequently asked questions
Why doesn't this calculator automatically handle daylight saving time?
Because daylight saving rules vary from country to country, sometimes change dates from one year to the next, and many countries worldwide don't apply them at all. Reliable automatic handling would require a continuously maintained time zone database, outside the scope of this static calculator. Check the UTC offset in effect on the date you're interested in before entering it.
How do I find a place's current UTC offset?
A search like "current time [city] UTC" generally gives the offset currently in effect, accounting for daylight saving time if applicable. This offset can change twice a year in countries that apply seasonal time changes.
What does a UTC offset with a half hour (like UTC+5:30) mean?
Some countries (India, notably) use a UTC offset that isn't a whole number of hours, for example UTC+5:30. This calculator accepts offsets in 30-minute steps to cover these cases — enter 5.5 to represent UTC+5:30.