Sunrise and sunset calculator
Choose a city or enter latitude and longitude, set the date and the time zone, and get sunrise, sunset, solar noon, the length of the day and the start and end of civil twilight. It opens on today's date.
Runs in your browser: nothing you enter is sent anywhere.
How to use it
- Pick a date. It starts with today.
- Choose a city from the list, or enter latitude and longitude (decimal degrees, north and east positive, a comma works as a decimal point). The button Use my location fills them from your device.
- Check the time zone. The times are shown on the clock of that zone, with summer time included automatically.
How it works
The calculation follows the NOAA solar calculator. It finds the Sun’s declination and the equation of time for the date, then the solar noon: the moment the Sun crosses the local meridian, at 12:00 UTC minus 4 minutes per degree of longitude east, corrected by the equation of time. Sunrise and sunset lie the Sun’s hour angle before and after noon, found from the latitude and declination for a Sun 0.833° below the horizon. Civil twilight uses 6° below. When that angle is never reached, the day is marked as polar day or polar night.
Worked example
London on 21 June 2026 (latitude 51.5074° N, longitude 0.1278° W): sunrise at 04:43 and sunset at 21:21 British Summer Time, solar noon at 13:02, so the day is 16 h 38 min. At the equator on the March equinox the day is 12 h 07 min, a few minutes more than 12 hours because of refraction and the Sun’s width.
Good to know
- The calculation treats the horizon as flat and at sea level. In mountains or valleys the visible sunrise differs.
- The times are rounded to the second but not that precise: treat them as good to a minute or two.
Frequently asked questions
How is sunrise defined?
Sunrise is when the upper edge of the Sun appears on the horizon. The calculation puts the Sun's centre 0.833° below the horizon, which allows for the Sun's radius and for the bending of light by the atmosphere.
What is civil twilight?
It is the time when the Sun is less than 6° below the horizon. Before sunrise it begins at dawn, after sunset it ends at dusk. Outdoors it is still light enough to see without artificial lighting.
Why can the Sun stay up or down all day?
Near the poles, in summer the Sun's path never reaches the horizon, giving polar day, and in winter it never rises, giving polar night. At Tromsø in Norway, for example, the Sun does not set on 21 June and does not rise on 21 December.
How accurate is it?
The method is the one used in the NOAA solar calculator. At middle latitudes expect agreement within a couple of minutes. Weather, hills and air pressure change the real moment the Sun is seen, and close to the poles the result is less exact.
Does the tool use my location?
Only if you press the location button, and the browser asks you first. The coordinates stay in your browser and are not sent anywhere.