Introduction
Need to know the time difference between two cities? Our Time Zone Difference Calculator makes it simple. Pick any two or three locations in the world, set a date and time, and instantly see how many hours and minutes apart they are. The tool handles Daylight Saving Time changes for you, so the results stay accurate all year long.
This calculator is useful when you need to schedule a call across time zones, plan a trip, or figure out what time it is right now in another country. You can compare up to three time zones at once, swap them with one click, and switch between 12-hour and 24-hour formats. A step-by-step breakdown shows you exactly how the math works, and a chart lets you see each zone's UTC offset side by side.
Just type a city name, country, or time zone abbreviation like EST or JST into the search box. The calculator does the rest.
How to Use Our Time Zone Difference Calculator
Enter two or three locations along with a date and time. The calculator will show you the exact time difference between each time zone, a step-by-step breakdown, and a visual chart of UTC offsets.
Time Format: Use the toggle at the top to switch between 12-hour (AM/PM) and 24-hour clock format. This changes how time is shown in every slot.
Location or Timezone: Type a city name, country, or time zone code (like "EST" or "Asia/Tokyo") into the search box in each slot. Pick the correct match from the dropdown list. The first two slots are required. The third slot is optional if you want to compare three zones at once.
Date: Choose the date you want to compare. This matters because daylight saving time can change the offset between zones on different dates.
Time: Enter the hour, minute, and second for your chosen slot. If you are in 12-hour mode, click the AM/PM button to toggle between morning and afternoon. When you change the time in one slot, the other slots update right away to show the same moment.
Use Current Time: Click this button inside any slot to fill all slots with the current time from your device. You can also click "Use Current Time (all slots)" in the toolbar at the top.
Swap Button: Click the round arrow button between the first two slots to switch their time zones with each other.
Calculate: Press this button to refresh the results. The calculator also updates live as you type, but you can press it any time to be sure.
Reset: Press this button to clear all your choices and return the calculator to its default settings of New York, London, and Mumbai.
What Is a Time Zone Difference?
The Earth is split into different time zones. Each zone follows its own clock. For most of the year, when it is noon in New York, it is already 5:00 PM in London. This happens because the Earth spins, and the sun reaches different places at different times. A time zone difference tells you how many hours and minutes apart two places are on the clock.
Why Time Zones Exist
Before time zones, every town set its own clock by the sun. This caused confusion, especially for trains and communication. In 1883, U.S. and Canadian railroads adopted a four-zone system.3 In 1884, a conference in Washington adopted the meridian through Greenwich as the prime meridian for longitude and timekeeping.4 Today each zone is set a number of hours ahead of or behind UTC (Coordinated Universal Time), which took effect internationally on January 1, 1972.4 For example, New York is UTC−5 in winter and UTC−4 in summer.
What Is UTC Offset?
A UTC offset is the number of hours and minutes a time zone adds to or subtracts from UTC. Tokyo has an offset of UTC+9, meaning it is 9 hours ahead of UTC.5 Some offsets are not whole hours. India is UTC+5:30, and Nepal is UTC+5:45.5
How Daylight Saving Time Affects the Difference
Many countries use Daylight Saving Time (DST). They move their clocks forward by one hour in spring and back by one hour in fall. This means the time difference between two cities can change depending on the date. In the United States, daylight saving time runs from the second Sunday of March to the first Sunday of November.1 In the UK, the clocks go forward on the last Sunday in March and back on the last Sunday in October.2 So London and New York are 5 hours apart for most of the year, but only 4 hours apart for a few weeks each spring and fall. Always check the difference for the specific date you need.
When You Need to Know the Time Difference
Knowing the exact time difference is useful when you need to schedule a call or meeting with someone in another country, catch a live event broadcast from a different region, plan travel across multiple time zones, or set a deadline that people in different places must follow. Getting it wrong can mean missing a flight, joining a meeting an hour late, or waking someone up in the middle of the night.
If you are coordinating across business days in different countries, keep in mind that weekends and holidays vary by region too.