Convert GMT to PST Greenwich Mean Time ↔ Pacific Standard Time Free Online Secure
Type a time in GMT and read it in PST straight away. The offset is −8 h, the arithmetic wraps at midnight, and the answer says which day it lands on.
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Through the day — Convert GMT to PST (Greenwich Mean Time ↔ Pacific Standard Time)
| GMT | PST |
|---|---|
| 00:00 | 16:00 |
| 03:00 | 19:00 |
| 06:00 | 22:00 |
| 09:00 | 01:00 |
| 12:00 | 04:00 |
| 15:00 | 07:00 |
| 18:00 | 10:00 |
| 21:00 | 13:00 |
Where these units come from
Until the middle of the nineteenth century every town kept its own noon, set by the sun overhead, and nobody minded that the next town was four minutes behind. Railways ended that: a timetable cannot be written for a hundred local noons. Britain put its railways on Greenwich time in 1847, and in 1884 the International Meridian Conference in Washington chose Greenwich as the prime meridian and sketched the twenty-four-hour scheme we still use. Greenwich Mean Time was the world's reference until 1972, when Coordinated Universal Time replaced it: UTC is kept by atomic clocks and tied back to the turning Earth by leap seconds. The abbreviations on this page name standard time — the winter setting — which is why each one is a fixed number of hours rather than something that drifts through the year.
Where you meet them
A time zone becomes real the moment two people in different places have to agree on one moment: a call between offices, a flight that lands before it took off, a market that opens while you are asleep, a deadline written in somebody else's afternoon. Server logs, train and flight schedules and anything stamped with a time are kept in UTC precisely so that the question can always be settled, no matter whose clock was on the wall.
Questions people ask
What about summer time?
The offsets here are standard-time offsets, the ones a zone keeps in winter. Where summer time is observed, the same places move one hour further on for part of the year and take a different name: Central European Time becomes Central European Summer Time, Eastern Standard Time becomes Eastern Daylight Time. The switching dates are not the same in every country, and the two hemispheres change in opposite months, so for a date inside a summer-time period add an hour to whichever side observes it.
Why isn't every difference a whole number of hours?
Because offsets are decided by governments, not by geometry. India is half an hour off the hour, at UTC+05:30; Nepal is three quarters, at UTC+05:45; the Chatham Islands are at UTC+12:45. Any of these can be changed by law, and several countries have moved their offset within living memory.
Is the answer exact?
Where both units are defined in terms of one another by whole numbers, yes — the page says so above the figure, and the only rounding is in how many digits are shown. Where the ratio has no finite decimal, the page shows twelve significant digits and says the relation is approximate rather than pretending otherwise.
Does anything I type leave my device?
No. The arithmetic runs in your browser; nothing is uploaded and there is no server to upload it to. Load the page once and it keeps working with the network switched off.
Greenwich time on a California clock
London and the American West Coast are about as far apart on the clock as two major English-speaking regions can be. When it is 16:00 in Greenwich in winter, it is 08:00 in San Francisco, and when the British working day ends at 17:00 the Californian one has barely begun at 09:00. If you want to convert GMT to PST, subtract eight hours: 18:00 GMT becomes 10:00 PST, 12:00 GMT becomes 04:00 PST, and 05:00 GMT becomes 21:00 PST on the previous calendar day.
This page gives you the rule, a table of every hour of the day, and an account of both zones, then explains why the gap sometimes shrinks to seven hours, how earthquake reports, stock opening bells, football kick-offs and spaceflight windows line up across the two clocks, and which mistakes to watch for. The calculation happens in your browser and nothing is uploaded.
How to convert GMT to PST
Take away eight hours
Pacific Standard Time is UTC−8 and Greenwich Mean Time is UTC+0, so the Pacific clock runs eight hours behind. Subtract eight from the GMT hour whenever you convert GMT to PST. If the answer would be negative, add twenty-four and step back one date. For example, 06:30 GMT gives −1:30, which becomes 22:30 PST the previous day.
Eight readings you can verify
00:30 GMT is 16:30 PST the day before. 06:15 GMT is 22:15 PST the day before. 09:00 GMT is 01:00 PST. 12:00 GMT is 04:00 PST. 15:45 GMT is 07:45 PST. 18:00 GMT is 10:00 PST. 21:30 GMT is 13:30 PST. 23:45 GMT is 15:45 PST. Notice how the first two land on the previous date and the rest do not.
A mental shortcut
Think in thirds of a day when you convert GMT to PST in your head. Eight hours is exactly one third, so GMT midnight to 08:00 corresponds to the previous afternoon and evening in California, GMT 08:00 to 16:00 to the Pacific night and early morning, and GMT 16:00 to midnight to the Pacific working day.
GMT as the Californian sees it
An evening zone
From the West Coast, GMT is the clock of the future: by the time San Francisco is eating lunch, Greenwich is already settling into the evening. Anything scheduled for the British morning therefore happens in the middle of the Californian night, and anything scheduled for the British evening is a Californian morning.
What the label hides
The term GMT may mean the zero-offset scale or the London wall clock. Between 29 March and 25 October 2026 the London wall clock is British Summer Time, UTC+1. If someone in London says “see you at 3 p.m. GMT” in June, ask which clock they mean, because the answer to “what time is that in Los Angeles?” differs by an hour.
Pacific Standard Time in practice
The cities it covers
Pacific time applies to California, Oregon, Washington and most of Nevada in the United States, to British Columbia in Canada, and to Baja California in Mexico. Los Angeles, San Francisco, San Diego, Sacramento, Portland, Seattle, Las Vegas and Vancouver all share it. The winter label is PST at UTC−8, and the summer label is PDT at UTC−7.
The industries it serves
The Pacific zone hosts the technology firms of Silicon Valley, the film and television studios of Hollywood, the aircraft makers and software companies of the Seattle area, and the ports of Los Angeles and Long Beach. A great deal of English-language news about these industries is stamped in Pacific time, which is why so many readers need to convert GMT to PST.
One abbreviation, three meanings
PST also stands for Philippine Standard Time (UTC+8) and Pakistan Standard Time (UTC+5). In this converter, PST is always the North American zone at UTC−8.
Eight hours and the working day
Almost no overlap
A London office open from 09:00 to 17:00 GMT is open from 01:00 to 09:00 PST. A Californian office open from 09:00 to 17:00 PST is open from 17:00 to 01:00 GMT. The two day-shifts touch only at 17:00 GMT, which is 09:00 PST. On a normal day, there is no shared office hour, so cross-coast meetings are set outside regular hours for at least one side.
Which side gives way
Many London-based teams accept an evening call at 17:00 to 18:00 GMT, which is 09:00 to 10:00 PST. Many Californian teams accept an early start at 07:00 or 08:00 PST, which is 15:00 or 16:00 GMT. The compromise, once you convert GMT to PST, is to meet at 16:30 GMT, which is 08:30 PST: the Londoner is at the end of the afternoon and the Californian has just arrived.
Flying the route
A flight leaving London at 11:00 GMT and lasting eleven hours lands at 22:00 GMT, which is 14:00 PST. The traveller seems to arrive in the middle of the afternoon on the same day on which they left, a gain of eight hours on the clock.
When the gap is seven hours instead of eight
The two calendars
The United States begins daylight saving time on the second Sunday of March and ends it on the first Sunday of November. Britain begins on the last Sunday of March and ends on the last Sunday of October. In 2026 the American dates are 8 March and 1 November, while the British dates are 29 March and 25 October.
Four odd weeks
From 8 to 28 March, Los Angeles is on PDT, UTC−7, while London remains on GMT, so the gap is seven hours. From 25 to 31 October, London is back on GMT while Los Angeles is still on PDT, and again the gap is seven hours. During the rest of the year the gap is eight hours: GMT to PST in winter, BST to PDT in summer.
How to handle it
The calculator above uses the winter difference. For a date in one of the four odd weeks, subtract seven hours instead: 17:00 GMT on 16 March is 10:00 PDT, not 09:00 PST. If the date is unclear, state the zone and the date in the message.
Earthquake bulletins
Why geologists use UTC
The United States Geological Survey publishes the time of each earthquake in UTC, which for this purpose is the same as GMT. A magnitude 4.7 event listed at 14:32 UTC happened at 06:32 PST in California. Residents who felt it after breakfast may need a moment to match the bulletin to their memory, and a “convert GMT to PST” calculation makes the match instant.
Aftershock sequences
Bulletins often list a main shock and a series of aftershocks. If the first is at 03:10 UTC and the next at 05:45 UTC, then in Los Angeles they occurred at 19:10 and 21:45 the previous evening. Keeping the date straight is half the work.
Stock market sessions
Wall Street from California
The main American equity session runs from 9:30 a.m. to 4:00 p.m. Eastern, which is 6:30 a.m. to 1:00 p.m. Pacific. In GMT, that is 14:30 to 21:00. A trader in San Francisco must be at the desk before sunrise, while a trader in London sees the opening bell shortly before 3:00 p.m.
The London overlap
The London market closes at 16:30 GMT, which is 08:30 PST, only two hours after New York opens. A Californian investor who watches both is therefore awake early and sees most of the overlap before 9:00 a.m.
Spaceflight from the California coast
Launch windows
Rockets that fly polar orbits from Vandenberg in California publish launch windows in Pacific time. A window opening at 10:30 PST opens at 18:30 GMT. A night launch at 22:15 PST goes off at 06:15 GMT the next day. Spotters in Britain who want a glimpse of the broadcast have to take the date into account.
Landing and recovery
Boosters that land on a drone ship in the Pacific are reported in the same clock. A landing announced for 10:41 PST is 18:41 GMT. If you convert GMT to PST for each event on the schedule, you end up with a timeline readable in London or Dublin.
Football fans on the West Coast
Early breakfast matches
A Saturday match with a 12:30 GMT kick-off starts at 04:30 PST. A 15:00 GMT match starts at 07:00 PST and a 17:30 GMT match at 09:30 PST. Californian supporters of English clubs gather in bars that open at dawn, and some stream on phones before work.
Midweek evenings
A midweek European fixture at 19:45 GMT is at 11:45 PST, in the middle of the working morning. At 20:00 GMT, it is noon. The match often finishes while American lunch is still on.
Television, awards and premieres
The gala hour
Major film awards start in the late afternoon in Los Angeles, around 17:00 PST, which is 01:00 GMT the next day. The ceremony runs for three or four hours, ending about 05:00 GMT. British viewers watch through the night or catch the highlights next morning.
Premiere releases
Streaming services often unlock a new series at midnight Pacific. That is 08:00 GMT. A British viewer eating breakfast can start the first episode at the same time as a Californian watching at midnight.
Remote work between London and the Bay Area
Asynchronous habits
Teams that span the two coasts rely on written updates. The British side posts a status report at 17:00 GMT, which arrives at 09:00 PST, in time for the Californian morning. The Californian side posts at 17:00 PST, which arrives at 01:00 GMT, ready for the British morning.
One live meeting a week
Many groups keep a single synchronous meeting. 16:30 GMT on Tuesday is 08:30 PST that same morning. A calendar entry should carry both times, and the “convert GMT to PST” calculation should be repeated after each clock change.
The full day in one table
GMT to PST, every hour
00:00 GMT becomes 16:00 PST (previous day). 01:00 GMT becomes 17:00 PST (previous day). 02:00 GMT becomes 18:00 PST (previous day). 03:00 GMT becomes 19:00 PST (previous day). 04:00 GMT becomes 20:00 PST (previous day). 05:00 GMT becomes 21:00 PST (previous day). 06:00 GMT becomes 22:00 PST (previous day). 07:00 GMT becomes 23:00 PST (previous day). 08:00 GMT becomes 00:00 PST. 09:00 GMT becomes 01:00 PST. 10:00 GMT becomes 02:00 PST. 11:00 GMT becomes 03:00 PST. 12:00 GMT becomes 04:00 PST. 13:00 GMT becomes 05:00 PST. 14:00 GMT becomes 06:00 PST. 15:00 GMT becomes 07:00 PST. 16:00 GMT becomes 08:00 PST. 17:00 GMT becomes 09:00 PST. 18:00 GMT becomes 10:00 PST. 19:00 GMT becomes 11:00 PST. 20:00 GMT becomes 12:00 PST. 21:00 GMT becomes 13:00 PST. 22:00 GMT becomes 14:00 PST. 23:00 GMT becomes 15:00 PST.
Reading the table
Each row shows one GMT hour and the matching Pacific hour, with a note when the date differs. The rows were computed with the same eight-hour subtraction that the converter uses when you convert GMT to PST.
Readings that include minutes
Ten more examples
01:05 GMT becomes 17:05 PST (previous day). 03:20 GMT becomes 19:20 PST (previous day). 05:50 GMT becomes 21:50 PST (previous day). 07:35 GMT becomes 23:35 PST (previous day). 10:10 GMT becomes 02:10 PST. 13:25 GMT becomes 05:25 PST. 16:40 GMT becomes 08:40 PST. 19:55 GMT becomes 11:55 PST. 22:15 GMT becomes 14:15 PST. 23:05 GMT becomes 15:05 PST.
The minutes never change
Because the difference is a whole number of hours, the minutes in the answer always match the minutes of the question. If they do not, you have misread the input.
Seattle, Portland and Vancouver
The northern end of the zone
The Pacific Northwest keeps the same Pacific time as California. The days are shorter in winter, with sunrise after 07:30 PST in Seattle in December, which is after 15:30 GMT. A Londoner planning a winter call to Seattle should know that the Pacific morning is also dark.
Film and visual effects
Vancouver and London are two of the world’s main centres for visual effects work. Shots reviewed at 10:00 PST in Vancouver are reviewed at 18:00 GMT in London, and artists in London sending files at 17:00 GMT deliver to Vancouver at 09:00 PST.
Neighbouring American zones
The ladder from GMT
Subtract five hours for Eastern, six for Central, seven for Mountain and eight for Pacific. Alaska is nine hours behind and Hawaii is ten. If a contact says “Mountain”, do not use eight hours.
One example hour in five zones
At 18:00 GMT the clocks read 13:00 in New York, 12:00 in Chicago, 11:00 in Denver, 10:00 in Los Angeles and 09:00 in Anchorage. Writing all of these in an invitation is one way to spare readers from having to convert GMT to PST on their own.
Examples with dates in four seasons
January
On Tuesday 20 January, 18:00 GMT is 10:00 PST. Both sides are on winter time, so the eight-hour rule applies.
March
On Tuesday 17 March, 18:00 GMT is 11:00 PDT. The United States moved to summer time on 8 March, so the gap is seven hours.
July
On Tuesday 21 July, 18:00 BST is 10:00 PDT. Both sides are on summer time, so the gap returns to eight hours.
November
On Tuesday 3 November, 18:00 GMT is 10:00 PST. Both sides are back on winter time after 1 November.
Checklist: how to convert GMT to PST
Before
Read the label
PST, PDT or PT? If it is PT and the date falls between 8 March and 1 November, treat it as PDT.
Use 24-hour time
Convert 4:15 p.m. to 16:15 before subtracting or adding.
After
Subtract eight hours
If the GMT hour is below 08:00, add twenty-four first.
Check the date
GMT hours from 00:00 to 07:59 fall on the previous date in California.
Online classes and bootcamps run from California
Students in Europe
A course taught live from Berkeley or Stanford at 10:00 PST begins at 18:00 GMT. That is evening in Britain and 20:00 in Bucharest, which suits adults studying after work. An afternoon session at 14:00 PST begins at 22:00 GMT, which is already too late for many European participants and is usually recorded.
Office hours and deadlines
Instructors who hold office hours from 16:00 to 17:00 PST are available from midnight to 01:00 GMT, so a student in London who wants to attend must stay up. Assignments due at 23:59 PST fall at 07:59 GMT the next morning, which is why European students often submit while having breakfast.
Planning a trip between the two coasts
The first day in California
A visitor who lands in Los Angeles at 14:00 PST has been awake since about 02:00 PST if they set out at 10:00 GMT and slept little on the aircraft. The body clock is already late in the evening: 14:00 PST is 22:00 GMT. Staying awake until 21:00 PST, which is 05:00 GMT, is the standard advice for adapting quickly.
Calling home
Calling London from California in the morning is easiest between 07:00 and 09:00 PST, because that is 15:00 to 17:00 GMT. After 09:00 PST the British office has closed and the family may be preparing for bed after 21:00 GMT. A short convert GMT to PST before packing your phone charger saves awkward calls.
Mistakes when you convert GMT to PST
Adding instead of subtracting
California is behind London. If your answer is later than the GMT time, you added.
Using five hours instead of eight
Five hours is the gap to New York. For the Pacific coast subtract eight.
Missing the previous date
Early morning in GMT is the previous evening in California. A deadline of 03:00 GMT on Friday is 19:00 PST on Thursday.
Confusing PST with Philippine time
Philippine Standard Time is UTC+8, not UTC−8. A colleague in Manila who writes PST means something else.
Frequently asked questions
What is the difference between GMT and PST?
Eight hours. PST is behind GMT.
How do I convert GMT to PST?
Subtract eight hours, adding twenty-four and stepping back a date if the result is negative.
What is 18:00 GMT in PST?
10:00 PST.
Why is the gap sometimes seven hours?
Because the United States and Europe change their clocks on different dates, creating four odd weeks.
Is anything sent to a server?
No. Your input stays in the browser.
More time zone converters
Related converters: Convert GMT to CET, Convert GMT to UTC, Convert EET to PST, Convert IST to PST, Convert PST to EET, Convert CET to GMT, Convert EST to CET, Convert CET to UTC, Convert IST to CST. For the reverse direction, open Convert PST to GMT.
To convert GMT to PST, in short, subtract eight hours, watch the date, and remember the four weeks in which the gap is seven. The work is done on your own device, with no account and no upload.