Sunrise and Sunset Calculator
Estimate sunrise, sunset and daylight hours for any date, latitude and longitude.
Last updated · View algorithm, constants and default inputs (JSON)
Results
About this calculator
Estimate sunrise, sunset and daylight from date and coordinates with a simplified solar model. Clock times are approximate UTC estimates; no local time-zone or daylight-saving conversion is applied. The model omits atmospheric refraction, elevation and the equation of time, so use a dedicated source for precise local times.
Worked example
calculated with the default values below
Date 2026-10-31 · Latitude (positive = north) 51.5 ° · Longitude (positive = east) -0.13 ° Sunrise (UTC hours) 7.33 h · Sunset (UTC hours) 16.69 h · Daylight 9.37 h · Solar noon (UTC) 12.01 h · Sunrise (UTC) 07:20 UTC · Sunset (UTC) 16:41 UTC
General background references
Disclaimer
These calculators give general date results. Public holidays, working-day conventions and time-zone rules are set locally and change, so confirm against the official calendar for anything legally or contractually binding.
Implementation source
This record describes the implementation used by this page. It is not independent validation. External references, when available, support only the stated formula or definition; estimates and custom rules retain their own assumptions.
Formula and variables
δ = 23.44° sin(2π(N−81)÷365); sunrise = 12 − λ÷15 − acos(−tan φ tan δ)÷15
- N
- Day of year
- φ
- Latitude (degrees)
- λ
- Longitude (degrees)
- δ
- Solar declination
Times in UTC. Solar noon = 12 − λ÷15; sunset = noon + H; daylight = 2H, where H = acos(−tan φ tan δ)÷15. Argument > 1 = polar night, < −1 = midnight sun.
Frequently asked questions
What time standard do the sunrise and sunset outputs use?
The model calculates approximate solar noon from longitude and displays sunrise and sunset clock times labeled UTC. It does not accept a time-zone or daylight-saving input. Its simple declination and hour-angle formula also omits atmospheric refraction, elevation and the equation of time, so verify exact local times with a dedicated source.