Time Zone Converter
Convert time between any two time zones
If you're looking to calculate the amount of time between any two dates, try our Date Difference.
Date & Time
How it works
Pick a date and time, select your "from" and "to" timezones, and the converter shows what time it is in the destination timezone.
Searching timezones
In the timezone dropdowns, you can search by: city name (e.g. "London", "Tokyo"), timezone abbreviation (e.g. "EST", "GMT"), or UTC offset (e.g. "UTC+5:30").
How time zones came to exist
Before the railways, every town kept its own local solar time, and noon was simply when the sun was highest. This was fine when travel was slow, but by the 1840s British railway companies found it impossible to publish reliable timetables when Bristol ran 10 minutes behind London. Great Western Railway adopted a single "railway time" based on Greenwich in 1840, and most of Britain had followed by 1847.
The same problem hit the US on a massive scale. On 18 November 1883, the American railroads unilaterally switched to four standardised time zones; a day known as "the Day of Two Noons" in cities that had to set their clocks back. The US government did not officially adopt the system until the Standard Time Act of 1918.
The international standard was established at the International Meridian Conference in Washington in 1884, where 25 nations agreed to divide the world into 24 hourly zones centred on the prime meridian at Greenwich, London. France abstained (they preferred Paris) and only aligned in 1911.
The same problem hit the US on a massive scale. On 18 November 1883, the American railroads unilaterally switched to four standardised time zones; a day known as "the Day of Two Noons" in cities that had to set their clocks back. The US government did not officially adopt the system until the Standard Time Act of 1918.
The international standard was established at the International Meridian Conference in Washington in 1884, where 25 nations agreed to divide the world into 24 hourly zones centred on the prime meridian at Greenwich, London. France abstained (they preferred Paris) and only aligned in 1911.
UTC, GMT, and offsets
GMT (Greenwich Mean Time) is based on solar time at the Royal Observatory in Greenwich. UTC (Coordinated Universal Time) replaced it as the global standard in 1972 and is kept by atomic clocks; it occasionally adds a leap second to stay within 0.9 seconds of solar time. For most practical purposes GMT and UTC are interchangeable, but UTC is the precise scientific standard.
Every timezone is expressed as an offset from UTC. India at UTC+5:30 and Nepal at UTC+5:45 are examples of the half- and quarter-hour offsets some countries adopted to better align with their geography.
Every timezone is expressed as an offset from UTC. India at UTC+5:30 and Nepal at UTC+5:45 are examples of the half- and quarter-hour offsets some countries adopted to better align with their geography.