What is the difference between a time zone and an offset?

An offset is a fixed number of hours from UTC, such as UTC+9. A time zone is a region with a history of offsets and daylight-saving rules; the same zone can have two offsets in one year. Converters that use regions, like this one, get summer time right.

Why do PST and EST stay three hours apart but EST and GMT do not?

The US zones change their clocks on the same dates, so their gap is constant. The UK changes on different dates (the last Sundays of March and October), so New York and London are five hours apart most of the year but four hours apart for a few weeks in spring and one week in autumn.

Does the converter use my computer's clock?

The live clocks use your device's current time and convert it to each zone; if your computer's clock is wrong, the clocks here will be too. The date-and-time converter does not depend on your clock, only on the values you enter.

Which zones do not use daylight saving?

India, Japan, South Korea, China, Singapore, Hong Kong, the Philippines, Indonesia, the UAE, Pakistan, South Africa, Brazil (since 2019), Argentina, Hawaii, most of Arizona and Western Australia keep one offset all year. The daylight-saving cards on each pair page show which side changes.

Is UTC the same as GMT?

For everyday purposes yes: both are UTC+0 in winter. UTC is the scientific standard and never changes; the UK's clock does, moving to BST (UTC+1) in summer. UltKit lists GMT as the London region and UTC as the fixed reference.

Can I convert a time for a past or future date?

Yes. Change the date field and the converter applies the daylight-saving rules for that date. Rules are taken from your browser's time-zone data, which is updated with the operating system.

Time Zone Converter

Compare any two time zones side by side. The clocks tick in real time, the converter takes a date and time on one side and shows the other, and daylight saving is applied from the official rules for the date you pick.

PST

Pacific Time

--:--

Now ·

EST

Eastern Time

--:--

Now ·

DateTime · PST

Eastern Time · UTC+0

—

How the converter decides the offset

Every zone here is an IANA time-zone region (America/New_York, Asia/Kolkata and so on), not a fixed number. That matters because most zone abbreviations hide two offsets: EST is UTC−5 but New York runs on EDT, UTC−4, from March to November. The converter asks your browser's time-zone database for the offset that applies on the exact date you enter, so a meeting in July and the same meeting in January convert differently when only one side observes daylight saving.

Abbreviations are also ambiguous. "CST" is Central Standard Time in Chicago, China Standard Time in Beijing and Cuba Standard Time in Havana; "IST" is India, Israel and Ireland. The list below names the region each code means on UltKit, and China's zone is listed separately so the two CSTs never get mixed up.

Daylight saving time

Pacific TimePST / PDT
UTC−8 in winter, UTC−7 in summer
US West Coast
Mountain TimeMST / MDT
UTC−7 in winter, UTC−6 in summer
US Mountain states
Central TimeCST / CDT
UTC−6 in winter, UTC−5 in summer
US Central states
Eastern TimeEST / EDT
UTC−5 in winter, UTC−4 in summer
US East Coast
Alaska TimeAKST / AKDT
UTC−9 in winter, UTC−8 in summer
Alaska
Hawaii TimeHST
No daylight saving; all year UTC−10
Hawaii
Atlantic TimeAST / ADT
UTC−4 in winter, UTC−3 in summer
Atlantic Canada
Coordinated Universal TimeUTC
No daylight saving; all year UTC+0
Worldwide reference
Greenwich Mean TimeGMT / BST
UTC+0 in winter, UTC+1 in summer
United Kingdom, Ireland, Portugal
Central European TimeCET / CEST
UTC+1 in winter, UTC+2 in summer
France, Germany, Spain, Italy, Poland
Eastern European TimeEET / EEST
UTC+2 in winter, UTC+3 in summer
Greece, Finland, Romania, Ukraine
Moscow TimeMSK
No daylight saving; all year UTC+3
Russia (Moscow)
India Standard TimeIST
No daylight saving; all year UTC+5:30
India
Pakistan Standard TimePKT
No daylight saving; all year UTC+5
Pakistan
Gulf Standard TimeGST
No daylight saving; all year UTC+4
UAE, Oman
Singapore TimeSGT
No daylight saving; all year UTC+8
Singapore, Malaysia
Hong Kong TimeHKT
No daylight saving; all year UTC+8
Hong Kong
China Standard TimeCST
No daylight saving; all year UTC+8
China
Philippine TimePHT
No daylight saving; all year UTC+8
Philippines
Western Indonesia TimeWIB
No daylight saving; all year UTC+7
Indonesia (Jakarta)
Japan Standard TimeJST
No daylight saving; all year UTC+9
Japan
Korea Standard TimeKST
No daylight saving; all year UTC+9
South Korea
Australian Eastern TimeAEST / AEDT
UTC+10 in winter, UTC+11 in summer
Sydney, Melbourne, Brisbane (no DST)
Australian Western TimeAWST
No daylight saving; all year UTC+8
Perth
New Zealand TimeNZST / NZDT
UTC+12 in winter, UTC+13 in summer
New Zealand
Brasília TimeBRT
No daylight saving; all year UTC−3
Brazil (São Paulo)
Argentina TimeART
No daylight saving; all year UTC−3
Argentina
South Africa TimeSAST
No daylight saving; all year UTC+2
South Africa
West Africa TimeWAT
No daylight saving; all year UTC+1
Nigeria
East Africa TimeEAT
No daylight saving; all year UTC+3
Kenya, Ethiopia

Three habits that prevent time-zone mistakes

Write the zone next to every time you send ("3 PM ET", not "3 PM"). Prefer the city over the abbreviation when the other person is abroad: "3 PM New York time" is clear in Tokyo, "3 PM EST" may be read as UTC−5 even in summer. And when a date is involved, state the date on both sides, because a late-evening call in California is already the next morning in India.

For recurring meetings, remember that the United States, the United Kingdom and the European Union change their clocks on different Sundays: the US switches on the second Sunday of March, Europe on the last Sunday of March, so the New York–London gap is four hours instead of five for about three weeks each spring. India, Japan, China and most of Asia never change, which shifts their difference to Europe and North America twice a year.

Other conversions with these zones

Frequently asked questions

What is the difference between a time zone and an offset?: An offset is a fixed number of hours from UTC, such as UTC+9. A time zone is a region with a history of offsets and daylight-saving rules; the same zone can have two offsets in one year. Converters that use regions, like this one, get summer time right.
Why do PST and EST stay three hours apart but EST and GMT do not?: The US zones change their clocks on the same dates, so their gap is constant. The UK changes on different dates (the last Sundays of March and October), so New York and London are five hours apart most of the year but four hours apart for a few weeks in spring and one week in autumn.
Does the converter use my computer's clock?: The live clocks use your device's current time and convert it to each zone; if your computer's clock is wrong, the clocks here will be too. The date-and-time converter does not depend on your clock, only on the values you enter.
Which zones do not use daylight saving?: India, Japan, South Korea, China, Singapore, Hong Kong, the Philippines, Indonesia, the UAE, Pakistan, South Africa, Brazil (since 2019), Argentina, Hawaii, most of Arizona and Western Australia keep one offset all year. The daylight-saving cards on each pair page show which side changes.
Is UTC the same as GMT?: For everyday purposes yes: both are UTC+0 in winter. UTC is the scientific standard and never changes; the UK's clock does, moving to BST (UTC+1) in summer. UltKit lists GMT as the London region and UTC as the fixed reference.
Can I convert a time for a past or future date?: Yes. Change the date field and the converter applies the daylight-saving rules for that date. Rules are taken from your browser's time-zone data, which is updated with the operating system.