Time Converter UK: GMT, BST & More

This time converter for the UK works out the current time in the United Kingdom and converts it to or from any other time zone worldwide. You enter a time and choose the source and target zones, and you get back the converted time, plus the UTC offset difference. The calculator below handles the core maths of UTC offsets and daylight saving changes, so you can see exactly what the time will be in London, New York, Tokyo, or anywhere else.

Formula

The conversion uses a simple offset model:

Converted time = Original time + (Target offset − Source offset)

Where:

• Original time is the time you start with, expressed as minutes after midnight (e.g., 14:30 = 870 minutes).
• Source offset is the UTC offset of the zone you are converting from, in minutes (e.g., GMT = 0, BST = +60).
• Target offset is the UTC offset of the zone you are converting to, in minutes.
• Converted time is the result, shown as a 24-hour clock time (HH:MM).

This is the standard method used by time zone converters: every zone is defined by its offset from Coordinated Universal Time (UTC), and daylight saving simply changes that offset by one hour during certain months.

Worked Example

Using the default values in the calculator: time = 12:00 (720 minutes after midnight), source = GMT (offset 0), target = EST (offset −300 minutes).

1. Convert the input time to minutes: 12:00 = 12 × 60 = 720 minutes.
2. Find the offset difference: target − source = −300 − 0 = −300 minutes.
3. Add the difference to the original time: 720 + (−300) = 420 minutes.
4. Convert back to hours and minutes: 420 ÷ 60 = 7 hours, 0 minutes → 07:00.

So 12:00 GMT is 07:00 EST (Eastern Standard Time, used in New York during winter). The calculator shows the same result: 07:00.

UK Time Zones: GMT and BST

The United Kingdom uses two time zones depending on the season:

• Greenwich Mean Time (GMT) – UTC+0, used from late October to late March. This is the UK’s standard time.
• British Summer Time (BST) – UTC+1, used from late March to late October. Clocks go forward one hour in spring and back one hour in autumn.

The transition dates are not fixed; they follow the European Union rule (until Brexit, and still in practice) of the last Sunday in March and the last Sunday in October. For example, in 2025, BST starts on 30 March and ends on 26 October. During BST, the UK is one hour ahead of GMT, so 12:00 GMT becomes 13:00 BST.

Historically, GMT was the world’s time standard before UTC replaced it in 1972. UTC is essentially the same as GMT for everyday purposes, but UTC is an atomic time scale, while GMT is based on the Earth’s rotation. The difference is less than a second, so for time conversion they are interchangeable.

How to Use the Converter

To convert a time between the UK and another zone, follow these steps:

1. Enter the time you want to convert in 24-hour format (e.g., 14:30 for 2:30 PM). The calculator uses minutes after midnight, so 14:30 is 870.
2. Select the source zone (the zone the time is currently in) from the drop-down.
3. Select the target zone (the zone you want to convert to).
4. Read the converted time and the offset difference in hours.

For example, if you have a meeting at 10:00 BST and you need to know the time in New York (EDT, which is UTC−4 during summer), the converter shows 05:00 EDT. The offset difference is −5 hours (BST is +1, EDT is −4, so −4 − (+1) = −5).

Common Mistakes and Misconceptions

One frequent error is forgetting that the UK is not always on GMT. During the summer months, the UK is on BST (UTC+1), so converting to New York in July requires using BST, not GMT. If you use GMT in summer, you will be one hour off.

Another common mix-up is confusing UTC and GMT. While they are effectively the same for civil time, UTC is the modern standard and does not observe daylight saving. GMT as a time zone does not observe daylight saving either, but the UK’s civil time does. So when someone says “GMT” in a UK context, they usually mean the winter time, not a permanent zone.

Also, note that the US and UK change clocks on different dates. The US begins daylight saving on the second Sunday in March and ends on the first Sunday in November, while the UK uses the last Sunday in March and October. This means for a few weeks in March and November, the offset difference between the UK and US is not the usual 5 or 8 hours – it can be 4 or 7 hours. Always check the current dates if you are converting around those periods.

Why the UK Has Two Time Zones

The UK’s daylight saving scheme was introduced during World War I to save fuel and extend daylight hours. The Summer Time Act 1916 established BST, and the practice has continued, with a few exceptions like during World War II when the UK used double summer time (UTC+2) and a period of year-round BST from 1968 to 1971 as an experiment. The experiment was abandoned because of accidents in the dark winter mornings, but the current system of GMT in winter and BST in summer has been in place since 1972.

The main benefit is that evenings have more daylight during the summer, which reduces energy use for lighting and encourages outdoor activities. The downside is that mornings are darker, which some argue is a safety issue for schoolchildren and workers. Several proposals to move the UK to permanent BST (UTC+1) have been debated, but none have been adopted.

Converting Between UK and Other Zones

Here are the standard offsets for common zones relative to UTC (without daylight saving):

• New York (Eastern): UTC−5 (EST) / UTC−4 (EDT)
• Los Angeles (Pacific): UTC−8 (PST) / UTC−7 (PDT)
• Tokyo (Japan): UTC+9 (no DST)
• Sydney (Australia): UTC+10 (AEST) / UTC+11 (AEDT)
• Mumbai (India): UTC+5:30 (IST, no DST)
• Berlin (Germany): UTC+1 (CET) / UTC+2 (CEST)

To convert from the UK to another zone, you simply subtract the UK’s offset from the target’s offset. For example, in winter (GMT, UTC+0), Tokyo (UTC+9) is 9 hours ahead, so 08:00 GMT is 17:00 JST. In summer (BST, UTC+1), Tokyo is 8 hours ahead, so 08:00 BST is 16:00 JST.

Frequently Asked Questions

Is the UK on GMT or BST right now?

It depends on the date. From the last Sunday in March to the last Sunday in October, the UK is on British Summer Time (BST, UTC+1). The rest of the year it is on Greenwich Mean Time (GMT, UTC+0). You can check the current date and the known transition dates to determine which applies.

What is the difference between GMT and UTC?

For time conversion purposes, there is no practical difference. GMT is a time zone based on the Earth’s rotation, while UTC is an atomic time standard. They are within a second of each other, and both are used as the reference for all other time zones. The UK uses GMT as its winter time zone, but the offset is identical to UTC.

How do I convert 2 PM UK time to US Eastern Time?

You need to know whether the UK is on GMT or BST, and whether the US is on standard or daylight time. In winter (GMT, EST), 14:00 GMT is 09:00 EST (subtract 5 hours). In summer (BST, EDT), 14:00 BST is 09:00 EDT (subtract 5 hours, because both have shifted by one hour). The tricky part is the transition weeks when one country has changed and the other hasn’t – then the difference is 4 or 6 hours instead of 5.

Why does the UK have daylight saving time?

Daylight saving time was introduced in 1916 to save energy during World War I by shifting daylight to the evening. It continues today to make better use of daylight during the longer summer days, reducing the need for artificial lighting and giving people more evening daylight for recreation. It is not required by any international law, but it is widely used in Europe and North America.

What is the time difference between London and New York?

London is 5 hours ahead of New York during standard time (GMT vs EST) and also 5 hours ahead during daylight time (BST vs EDT), because both zones shift by one hour on roughly similar schedules. However, during the transition weeks in March and November, the difference can be 4 or 6 hours. For example, in late March, the UK may have already moved to BST while New York is still on EST, making the difference 4 hours.

Does the UK use 24-hour time?

In writing, the UK commonly uses the 24-hour clock for schedules, transport timetables, and official documents (e.g., 14:30). In everyday speech, people often use the 12-hour clock with AM/PM (e.g., 2:30 PM). Both are understood, and time converters typically accept 24-hour input for clarity.

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in t | Time (minutes after midnight) | - | 720 | 0
sel from | From zone | UTC=0, GMT=0, BST=60, EST=-300, CST=-360, MST=-420, PST=-480, CET=60, IST=330, JST=540, AEST=600
sel to | To zone | GMT=0, BST=60, EST=-300, CST=-360, MST=-420, PST=-480, CET=60, IST=330, JST=540, AEST=600
out conv | Converted time | clock | t + (to - from) | 0
out offset | Offset difference | hours | (to - from) / 60 | 1