Calculate daylight duration for any location and date, see the minutes the day is gaining or losing, and compare the year's longest and shortest days.
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Enter a latitude, longitude, date and UTC offset (or tap an example city) to get the exact length of daylight, how many minutes the day is gaining or losing compared with the day before, and how that duration swings between the year's longest and shortest days. It works from the equator, where days stay near 12 hours, to the poles, where the sun can stay up or down for months.
Day length, or daylight duration, is the time between sunrise and sunset — the span the sun is above the horizon. It depends on your latitude and the date, because Earth's 23.4° axial tilt swings the sun's path north and south through the year. Near the equinoxes the day changes fastest (a few minutes per day at mid-latitudes); near the solstices it briefly holds steady before reversing. At the equator daylight barely moves from about 12 hours, while beyond the polar circles it can reach 24 hours or drop to zero.
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This calculator answers 'how long is the day and how is it changing' — the total daylight duration and how many minutes you gain or lose each day. The Sunrise & Sunset Calculator answers 'at what time' — the exact clock times of sunrise, sunset, solar noon and twilight. Use this one for the duration and trend, and that one for the actual times.
It depends on latitude and season. Around the equinoxes the day changes fastest — roughly 2–3 minutes per day at mid-latitudes and much more near the poles. Around the solstices the change slows almost to zero for a couple of weeks, which is why late June and December feel like the days are turning. At the equator the length barely moves all year.
Two effects add a few minutes: the atmosphere refracts sunlight so the sun is visible while it is still geometrically below the horizon, and sunrise and sunset are timed to the sun's upper edge, not its center. Together they push equinox daylight to about 12 hours and 7 minutes rather than exactly 12.
No. Longitude and time zone shift sunrise and sunset by the same amount, so the gap between them — the daylight duration — is unchanged. Only your latitude and the date set the length. The UTC offset here only affects the clock times shown for sunrise, sunset and solar noon.
Above the Arctic and Antarctic circles the day length can reach a full 24 hours (midnight sun) or fall to zero (polar night) for weeks or months. The calculator flags these cases instead of showing a normal duration, and the sunrise and sunset fields read as no event.