The time of the time zone, in which the Royal Greenwich Observatory was once located near the British capital, was adopted as the zero point of reference for time zones. Greenwich Mean Time is abbreviated as GMT (Greenwich Mean Time). A revised standard is now in force, which is designated as UTC (Coordinated Universal Time). It differs from Greenwich by less than one second and is used more often in accurate calculations, and when determining the time of day in different parts of the planet, Greenwich time is still relevant.
Instructions
Step 1
Determine the time offset of your time zone from the Greenwich meridian. You can find it out, for example, from the system time settings in the operating system of your computer. Click the clock in the notification area of the taskbar with the left mouse button, and an additional panel with a calendar and an analog clock will pop up on the screen. In the lower part of it there is a link "Change the date and time settings" - click on it. The system will open an additional settings window with three tabs, one of which is called "Date and Time" and has a section "Time Zone". In this section, you will see the shift of your local time relative to the Greenwich meridian - the corresponding inscription can be, for example, this: "UTC +04: 00 Volgograd, Moscow, St. Petersburg". This means that your operating system's system clock is four hours ahead of time zone zero.
Step 2
Subtract the time offset for your time zone from the current time in order to determine the corresponding GMT time. For example, if your clock shows 26 minutes past nine in the morning, and the time zone corresponds to Moscow time, then this shift is equal to four hours, which means that your GMT time is 26 minutes after five in the morning.
Step 3
Use an online service to determine Greenwich Mean Time if you have Internet access. This is an even easier way. For example, you can follow the link https://time100.ru/gmt.html and you will see the current time by Greenwich Mean Time immediately, without additional calculations.
Step 4
Use the built-in functions of the programming language if you need to programmatically determine Greenwich time - they are provided in most scripting languages. Most often, such functions refer to UTC time, and this is reflected in their names. For example, in PHP these are the gmdate and gmmktime functions, in JavaScript - a whole group of functions (getUTCDate, getUTCDay, getUTCMilliseconds and others), in MQL5 - TimeGMT, etc.
