Convert PST to GMT Pacific Standard Time ↔ Greenwich Mean Time Free Online Secure
Type a time in PST and read it in GMT 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 PST to GMT (Pacific Standard Time ↔ Greenwich Mean Time)
| PST | GMT |
|---|---|
| 00:00 | 08:00 |
| 03:00 | 11:00 |
| 06:00 | 14:00 |
| 09:00 | 17:00 |
| 12:00 | 20:00 |
| 15:00 | 23:00 |
| 18:00 | 02:00 |
| 21:00 | 05:00 |
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.
When your schedule is in Pacific time and your readers are in Greenwich time
Suppose you work in Los Angeles, San Francisco, Seattle or Vancouver and you are sending a schedule to colleagues, clients or fans in Britain, Ireland or West Africa. Your calendar says 9:00 a.m. PST, and theirs says GMT. To convert PST to GMT, add eight hours. A 9:00 a.m. start is 17:00 GMT, a noon deadline is 20:00 GMT, and a 6:00 p.m. broadcast is 02:00 GMT on the following date. The date matters as much as the hour, because anything after 4:00 p.m. PST has already crossed midnight in Greenwich.
On this page you will find the rule, two lookup tables, a profile of each zone, an explanation of the weeks when the gap is seven hours instead of eight, and a collection of scenarios from software releases to film production. All of the arithmetic runs in your browser, and none of the numbers you type are sent to a server.
The addition behind a “convert PST to GMT” calculation
Add eight hours to the Pacific time
PST sits at UTC−8 and GMT at UTC+0. The Greenwich clock is therefore eight hours ahead. Starting from a 24-hour reading on the Pacific clock, add eight whenever you convert PST to GMT. If the sum is 24 or more, subtract 24 and advance the date by one. 19:30 PST plus eight is 27:30, so the answer is 03:30 GMT the next day.
Eight readings to anchor your intuition
00:30 PST is 08:30 GMT. 06:15 PST is 14:15 GMT. 09:00 PST is 17:00 GMT. 12:00 PST is 20:00 GMT. 15:45 PST is 23:45 GMT. 18:00 PST is 02:00 GMT the next day. 21:30 PST is 05:30 GMT the next day. 23:45 PST is 07:45 GMT the next day. The four earliest stay on the same date, the three latest cross into the following date.
The 4 p.m. landmark
When it is 16:00 on the Pacific coast, it is exactly midnight in Greenwich. Everything before that hour shares its date with Greenwich, and everything after belongs to the next date there. If you remember only one thing when you convert PST to GMT, remember that boundary.
Pacific Standard Time, from the sender’s chair
One clock for a very large economy
California alone would rank among the largest economies in the world, and with Oregon, Washington, Nevada, British Columbia and Baja California it shares a single winter clock. Entertainment, aviation, software, shipping and agriculture all run on it. When any of them publishes a time without a zone, the zone is usually Pacific.
Summer and winter
From the second Sunday of March to the first Sunday of November, Pacific time is PDT, UTC−7. The rest of the year it is PST, UTC−8. In headlines and press releases, the shorthand “PT” covers both. Because the converter on this page uses a fixed offset of eight hours, it describes the winter relationship, and you adjust by one hour for the odd weeks described below.
Greenwich Mean Time, from the reader’s chair
A winter clock in Britain and a permanent one elsewhere
GMT is the standard time of Britain and Ireland from late October to late March and the permanent clock of Iceland and several West African countries. In computing it also appears in HTTP headers and server logs as a synonym for UTC. For a reader, “GMT” signals a fixed reference with no seasonal changes, which makes it a convenient target when you publish something worldwide.
The summer exception
In Britain, between 29 March and 25 October 2026, the wall clock is British Summer Time, UTC+1. People there may still write “GMT” out of habit. If your recipient is a person rather than a program, check which clock they mean when you convert PST to GMT.
What an eight-hour gap does to the day
Working hours barely touch
When a Californian team is in the office from 09:00 to 17:00 PST, a London team sees them at their desks from 17:00 to 01:00 GMT. The British office, open from 09:00 to 17:00 GMT, is open from 01:00 to 09:00 PST. The two shifts meet at a single moment, 17:00 GMT, which is 09:00 PST, and never overlap beyond it.
The practical compromise
Most teams that run a “convert PST to GMT” calculation for a recurring meeting pick a call at 08:00 PST, which is 16:00 GMT. The Californian has had a coffee and the Londoner still has an hour to go. The alternative is a call at 17:00 GMT that is 09:00 PST, tolerable for the Californian, but it pushes the Londoner to the very end of the working day.
Flying east
An overnight flight from San Francisco that leaves at 16:00 PST, which is midnight GMT, and takes about ten hours and forty-five minutes lands at 10:45 GMT. The passenger has lost a night of sleep and arrives with half of the British day gone. The clock shows a gain of eight hours on the way east.
Seven hours instead of eight: the exceptions
Whose clocks move when
Pacific clocks go forward on the second Sunday in March and back on the first Sunday in November. British clocks go forward on the last Sunday in March and back on the last Sunday in October. For 2026, the Pacific dates are 8 March and 1 November, and the British dates are 29 March and 25 October.
Counting the odd weeks
Between 8 and 28 March, California runs on PDT (UTC−7) while Britain still runs on GMT: the gap is seven hours. Between 25 and 31 October, Britain is already back on GMT while California is still on PDT: seven hours again. That makes four weeks of the year. For example, 10:00 PDT on 18 March is 17:00 GMT, not 18:00.
What the calculator does
The page applies eight hours. If you are converting a Pacific time in one of the four odd weeks, remove one hour from the result. At every other time of year the gap is eight hours, whether the labels are PST and GMT in winter or PDT and BST in summer.
Release trains and code freezes
A deploy window in two clocks
Software teams in the Bay Area often schedule releases for Tuesday morning at 09:00 PST, because the engineers are fresh and the weekend is far away. In London, that is 17:00 GMT, the end of the working day for the support team that will receive the tickets. A change that goes wrong at 09:30 PST reaches the on-call engineer in Britain at 17:30 GMT, when they are heading home.
Writing it in the runbook
A good runbook states the window in both zones and notes the date. If the release is on 17 March, when the clocks have already moved in California, write 09:00 PDT and 16:00 GMT. A “convert PST to GMT” calculation reminder in the checklist avoids shipping at the wrong hour.
Film production and overnight turnaround
A pipeline that never sleeps
Productions that shoot in Los Angeles and finish visual effects in London benefit from the eight-hour gap. A day of shooting that wraps at 18:00 PST sends its files at 02:00 GMT, and London artists who arrive at 09:00 GMT find the material waiting. Their notes, returned by 17:00 GMT, appear on the production’s desks at 09:00 PST, at the start of the Californian day.
Why it works
Each side works while the other sleeps, giving the project a nearly continuous schedule. The key is a shared timeline. When the studio publishes a delivery deadline of “noon PST”, the London team converts it to 20:00 GMT and plans accordingly.
Live premieres and online broadcasts
Setting the start time
A creator in Los Angeles who schedules a live premiere for 12:00 PST should know that British viewers will see it at 20:00 GMT, a comfortable evening slot. A premiere at 17:00 PST is at 01:00 GMT, a time when most British viewers are asleep and when European viewers rely on the replay.
Time stamps in the chat
Chat logs usually show each viewer’s own local time, so the same message is stamped 12:03 on one screen and 20:03 on another. If you are recording a transcript in a spreadsheet, use the “convert PST to GMT” calculation on the Pacific entries to bring all stamps into GMT first.
Concerts and theatre
Curtain times
A concert at the Hollywood Bowl that begins at 8:00 p.m. PST starts at 04:00 GMT. A matinee at 2:00 p.m. PST starts at 22:00 GMT. A British fan watching a live stream of the evening concert would need to stay up until the small hours or watch a recording on the next day.
Reverse planning
Promoters who want a British audience to watch live often schedule a Californian early afternoon performance, say 1:00 p.m. PST, which is 21:00 GMT. It is a compromise that suits both audiences, with a pleasant Californian lunch hour and a British evening.
Weather forecasts and bulletins
Forecast discussions
Regional forecast offices in the American West publish text discussions several times a day in local time. A bulletin issued at 3:30 a.m. PST appears at 11:30 GMT. A discussion at 3:00 p.m. PST appears at 23:00 GMT. People who follow Pacific storms from Europe can match them with the satellite images published in UTC.
What to watch for
Storm warnings are often stated as “through 4:00 p.m. PST Thursday”. Converted, this is “through midnight GMT between Thursday and Friday”, a date that is easy to misread. Keep the date with the time when you convert PST to GMT.
Pacific time in the news
Embargoes and releases
Press embargoes in American technology news are often lifted at 6:00 a.m. PST, which is 14:00 GMT. A British outlet that publishes at 14:00 GMT is publishing simultaneously with the American ones. If you have an interview that closes at 3:00 p.m. PST, the British story must wait until 23:00 GMT.
Reading datelines
An article stamped “Updated 4:45 p.m. PST” was updated at 00:45 GMT on the following date. Researchers who build timelines from news archives need to convert the stamps before sorting them.
Every hour in one table
PST to GMT
00:00 PST is 08:00 GMT. 01:00 PST is 09:00 GMT. 02:00 PST is 10:00 GMT. 03:00 PST is 11:00 GMT. 04:00 PST is 12:00 GMT. 05:00 PST is 13:00 GMT. 06:00 PST is 14:00 GMT. 07:00 PST is 15:00 GMT. 08:00 PST is 16:00 GMT. 09:00 PST is 17:00 GMT. 10:00 PST is 18:00 GMT. 11:00 PST is 19:00 GMT. 12:00 PST is 20:00 GMT. 13:00 PST is 21:00 GMT. 14:00 PST is 22:00 GMT. 15:00 PST is 23:00 GMT. 16:00 PST is 00:00 GMT (next day). 17:00 PST is 01:00 GMT (next day). 18:00 PST is 02:00 GMT (next day). 19:00 PST is 03:00 GMT (next day). 20:00 PST is 04:00 GMT (next day). 21:00 PST is 05:00 GMT (next day). 22:00 PST is 06:00 GMT (next day). 23:00 PST is 07:00 GMT (next day).
How to read the rows
Each entry pairs one Pacific hour with its Greenwich hour and notes when the date changes. The rows were computed by adding eight hours, which is exactly what the calculator does when you convert PST to GMT.
Minutes included
Ten further readings
01:05 PST is 09:05 GMT. 03:20 PST is 11:20 GMT. 05:50 PST is 13:50 GMT. 07:35 PST is 15:35 GMT. 10:10 PST is 18:10 GMT. 13:25 PST is 21:25 GMT. 16:40 PST is 00:40 GMT (next day). 19:55 PST is 03:55 GMT (next day). 22:15 PST is 06:15 GMT (next day). 23:05 PST is 07:05 GMT (next day).
The minutes stay put
A whole-hour difference leaves minutes untouched. If your answer has different minutes from your input, check your typing.
Neighbouring zones from Greenwich
The ladder
From GMT, subtract five hours for Eastern, six for Central, seven for Mountain and eight for Pacific. Alaska is nine and Hawaii is ten. A phrase like “Mountain Time” should not be treated as Pacific.
One moment, five clocks
When it is 09:00 in Los Angeles, it is 10:00 in Denver, 11:00 in Chicago, 12:00 in New York and 17:00 in London. Presenting all five in an invitation is a courtesy that spares readers from having to convert PST to GMT on their own.
Dated examples in four seasons
Winter
On Thursday 22 January, 13:30 PST is 21:30 GMT. Both sides are on standard time, so the gap is eight hours.
Early spring
On Saturday 21 March, 13:30 on a California clock is PDT, and Greenwich is at 20:30. The United States moved on 8 March while Britain moves on 29 March, so the gap is seven hours.
Summer
On Saturday 25 July, 13:30 PDT is 21:30 BST. Both are on summer time, so the gap is back to eight hours.
Late autumn
On Monday 26 October, 13:30 PDT is 20:30 GMT, because Britain went back to winter time on 25 October while California stays on summer time until 1 November.
Checklist: how to convert PST to GMT
Before the sum
Read the middle letter
In PST the S is for standard, and in PDT the D is for daylight. If the source says PT, use the calendar: from 8 March to 1 November it is PDT.
Choose the 24-hour format
Convert 3:30 p.m. to 15:30 and 12:00 a.m. to 00:00 to avoid mistakes.
The sum itself
Add eight
If the total exceeds 24:00, subtract 24 and move to the next date.
Test the landmark
16:00 PST must come out as midnight GMT. If your method gives something else, it is wrong.
Students, applications and exam sittings
Deadlines set in Pacific time
Universities on the West Coast often close applications at 11:59 p.m. Pacific. In Greenwich that moment is 07:59 on the following morning. A British applicant who is still revising the personal statement at 06:00 GMT is therefore inside the window, even though the calendar in London already shows the next day.
Remote exams
An online proctored exam that starts at 8:00 a.m. PST begins at 16:00 GMT. Students in Europe who sit the same paper must plan the afternoon around it, and a “convert PST to GMT” calculation before the day avoids the classic mistake of turning up eight hours early or late.
Farms, ports and logistics
The Pacific supply chain
Container ships that arrive at the ports of Los Angeles and Long Beach are scheduled for berths in local time. A berth window that opens at 06:00 PST opens at 14:00 GMT, so a shipping agent in London can watch the first crane lift at lunchtime.
Perishable goods
Growers in the Central Valley ship berries and vegetables overnight for next-day delivery. A truck that leaves at 20:00 PST departs at 04:00 GMT, and a buyer in Britain sees the departure notice before breakfast. When a delay is announced at 02:00 PST, the buyer receives it at 10:00 GMT.
Mistakes to avoid when you convert PST to GMT
Subtracting by habit
Greenwich is east of California, so its clock is ahead. A result smaller than the starting time means you subtracted.
Using five hours for the Pacific
Five hours separates GMT from the Eastern zone. The Pacific needs eight.
Keeping the old date
An event at 8:00 p.m. PST on Thursday takes place at 04:00 GMT on Friday. Keeping Thursday sends people a day early.
Mistaking the abbreviation
Philippine Standard Time is UTC+8, not UTC−8. A message from Manila that says PST requires a different calculation.
Frequently asked questions
How far apart are PST and GMT?
Eight hours. GMT is ahead.
What is the formula to convert PST to GMT?
Pacific hour plus eight, minus 24 if the total reaches 24.
What is 10:00 a.m. PST in GMT?
18:00 GMT.
When is the gap seven hours?
When California is already on summer time and Britain is not: 8 to 28 March and 25 to 31 October in 2026.
Is my input stored?
No. It stays in your browser.
Related time zone converters
You might also want Convert PST to WET, Convert PST to EET, Convert UTC to GMT, Convert CET to GMT, Convert GMT to CST, Convert CET to PST, Convert IST to EET, Convert IST to EST, Convert GMT to EET. To go the other way, use Convert GMT to PST.
In brief, to convert PST to GMT you add eight hours, remember the 4 p.m. landmark at which the date changes, and allow for the four weeks in which the gap is seven. The calculation never leaves your device and needs no account.