Day Length Calculator
Day length from sunrise to sunset for the selected location and date.
By Aryan Khan, Founder & Editor · Updated October 2026
For example, London gets 16 hours 39 minutes of daylight on 21 June 2026 and just 7 hours 50 minutes on 21 December (computed) — the same city living two different lives half a year apart.
How to use Day Length Calculator
Sunrise to sunset, counted — with the poles handled honestly:
The Day Length Calculator computes the hours of daylight between sunrise and sunset for any place and date, including polar cases where the answer is honestly zero or twenty-four. Enter a location and date and read the day's length — for gardens, trips and feeling the seasons in numbers.
- 1Set location and date.
- 2Read day length.
What people use Day Length Calculator for
1. Garden and growing decisions
Day length drives plant behaviour as much as temperature does. Photoperiod-sensitive crops read this number; so should the gardener choosing what to sow when.
2. Trip planning by light
A December city break in Edinburgh runs on under seven hours of daylight; the same trip in June gets seventeen. Itinerary density should follow the Sunrise Sunset Calculator's clock, not optimism.
3. Solar and energy estimates
Day length caps the day's possible sunshine and frames panel expectations before weather takes its share — the geometric ceiling on every solar estimate.
4. Chasing or fleeing the midnight sun
North of the Arctic Circle the calculator returns 24 hours in season — the fact behind the trip, computed for your exact dates rather than a brochure's 'summer'.
Worked examples
Computed for New York: 15 hours 06 minutes on 21 June 2026 (sunrise 05:24, sunset 20:30) against 9 hours 15 minutes on 21 December (07:16–16:31). Six hours of swing — the whole difference between a summer evening and a winter commute in the dark, twice.
On the equator every day of the year is about 12 hours 7 minutes — not exactly 12, because the sunrise convention counts the Sun's upper limb with refraction. The boring line on the graph is a subtlety wearing a disguise.
Day length at the solstices (computed)
Standard solar algorithm, 2026 solstice dates — the year's two extremes by latitude.
| Place | 21 June | 21 December |
|---|---|---|
| Quito (equator) | ≈12 h 07 m all year | ≈12 h 07 m all year |
| New York (40.7°N) | 15 h 06 m | 9 h 15 m |
| London (51.5°N) | 16 h 39 m | 7 h 50 m |
| Reykjavik (64.1°N) | ≈21 h | ≈4 h 10 m |
| Tromsø (69.7°N) | 24 h (midnight sun) | 0 h (polar night) |
Day length is sunrise-to-sunset on the standard horizon. Twilight adds usable light at both ends — civil twilight alone can add an hour a day at high latitudes in summer.
How many hours of daylight, exactly?
Day length is latitude and date, nothing else: the tilt of Earth's axis decides how long your hemisphere's daily arc keeps the Sun above the horizon. This tool computes it for any place and date with the NOAA algorithm, reports the duration in hours and minutes alongside sunrise, sunset and solar noon, and makes the seasonal story legible — approach a solstice and the number stretches or shrinks toward its annual extreme, which at high latitudes becomes the drama of midnight sun and polar night.
The result matters more than people expect: solar-panel yield estimates, crop and garden planning, photography scheduling, depression-aware winter planning, and trip timing ('how much light will the hike actually get?'). Elevation barely moves the number and the page says so; refraction conventions are stated, not smuggled. Pair it with the sunrise-sunset calculator for clock times, the moon-phase tool for the night counterpart, and the geographic-lines pages to see the latitudes — tropics and polar circles — that govern the whole system.
How to interpret the result
The most common errors come from using a correct result to answer the wrong geographic question. Keep these points in mind for Day Length Calculator:
- For photography, plan around sun altitude, not clock time: golden hour is an altitude band, so its clock time migrates with the seasons even at a fixed place — the calculator's windows handle that for you.
- When comparing day length across a year, remember the curve is your latitude's signature: near-equatorial sites hover at twelve hours while high latitudes swing wildly. Choose expectations by latitude, not by calendar folklore.
Limits & appropriate use
Solar arithmetic's limits are small but real: the official zenith encodes average refraction, not today's atmosphere; coordinates are rounded to your input's precision; and terrain is absent unless you add height yourself — a mountain rises the sun late and the formulas won't know. Time adds the political layer: zones and DST are human law, and western edges of big zones (Spain, western China) make solar noon wander hours from clock noon. Every output here therefore carries its convention and both clocks, because an unanchored sunrise time is an argument, not a fact.
Lunar and seasonal outputs carry their own gentle limits: phase from the synodic approximation is hours-precise, which outruns every planning need but not ephemeris science; day length is geometric daylight, not sunshine, and clouds belong to climate's department. Escalation is rare and well-defined — astronomical almanacs and ephemerides for science, terrain-aware apps for mountain photography, and the tz database maintainers whenever a government invents a new DST rule at 48 hours' notice, as they delight in doing.
- Science-grade ephemerides → astronomical almanacs/JPL horizons.
- Mountain sunrise/sunset → terrain-aware horizon adjustments.
- Legal daylight definitions → jurisdictional statutes (they vary!).
Data & methodology
The shared daylight chart samples calculated day length every three days across 2025; it is an annual overview, not a date-specific input.
For source details, licences and model limitations, see Data Sources and Methodology.
Key terms worth knowing
- Civil twilight
- Sun between 0° and −6°: usable outdoor light without lamps.
- Synodic month
- The 29.53-day new-moon-to-new-moon cycle behind phases.
Editorial guidance: MapBench explains the method and limitations so the tool can be used as a transparent reference, not as a black-box answer. For legal boundaries, safety-critical routing, surveying, engineering, regulated decisions or official statistics, verify the result with the responsible authority or a qualified professional.
Category: Sun & Moon. Results are intended for everyday analysis and planning unless a page explicitly states otherwise.
Method, assumptions & limits
- This tool’s method
- The shared daylight chart samples calculated day length every three days across 2025; it is an annual overview, not a date-specific input.
- Before relying on the answer
- Check the date, location and time zone together. A solar or lunar event is tied to all three, and some events do not occur at high latitudes on a given date.
- What the result cannot establish
- A calculated event assumes the model's horizon and atmospheric conventions. Buildings, terrain and local weather can alter what you observe.
Coverage: Worldwide. Search, basemap and external data requests may use third-party services; browser-based does not mean every operation is offline. Read the source and licence notes, calculation methodology and privacy policy. If a result looks inconsistent, report a correction with the inputs and mode used.
Frequently asked questions
Clear answers about the calculation, accuracy and appropriate use.
Polar day?
Near poles day length can be 0 or 24 hours.
Are sunrise and solar times exact to what I will see?
Calculated events use astronomical geometry. Terrain, buildings, weather and atmospheric conditions can shift what an observer actually sees.
Does daylight saving change the Sun's position?
No. Daylight saving changes the civil clock label, not solar geometry. Timezone rules affect displayed local time.
Why can polar locations show unusual results?
High latitudes can have days when the Sun does not rise or set, so some solar events legitimately do not occur on a selected date.
What counts as the 'day' here?
Sunrise to sunset, using the standard convention: the Sun's upper edge at the horizon, with average atmospheric refraction included (−0.83°). It is the almanac definition, not the moment the sky first brightens.
Why is the equinox day not exactly 12 hours?
The same convention: limb-plus-refraction buys a few extra minutes, and the equinox itself rarely falls on the date at your longitude. Most places see their true 12-hour day a few days off the equinox — the 'equilux'.
How fast does day length change?
Fastest at the equinoxes — around 2–3 minutes a day at mid-latitudes, more toward the poles — and not at all at the solstices, where the curve flattens. September steals daylight faster than December ever did.
Does elevation lengthen my day?
Yes, slightly: a higher horizon view sees the Sun earlier and later — roughly a few minutes per 1,000 m in open country. Mountains on the horizon take back with interest what altitude gives.
What about places inside the polar circles?
In season the answer is the honest extreme: 24 hours (the Sun never sets) or 0 (it never rises). The calculator reports those rather than failing — they are the correct answers for real dates and towns.
Daylight saving — does it change day length?
No. Clock labels move an hour between morning and evening; the sunrise-to-sunset total is untouched. The base FAQ on this page says it plainly because everyone asks once.
Can I get a whole year for one place?
Day-by-day queries build the picture; the pattern is a smooth annual wave peaking at your summer solstice. Gardeners and photographers often chart the year around a few anchor dates from this calculator.
Why do sunrise and sunset not balance around noon?
Solar noon is rarely clock noon — longitude within the time zone and the equation of time shift it. Day length only counts the span; where the span sits in the clock day is the Sunrise Sunset Calculator's story.
Related tools and resources
The endpoints: the Sunrise Sunset Calculator; twilight's bonus: the Civil Twilight Calculator; polar extremes: the Polar Day Night Checker; live view: the Day Night Map.
More free tools
Sources, methodology & editorial trust
- ✓ Browser-first processing where supported
- ✓ External sources are documented
- ✓ No account required for public tools
- ✓ Review data sources
Calculations are documented with their assumptions, limitations and source context rather than presented as unexplained answers.
Reviewed and maintained by Aryan Khan, Founder & Editor of MapBench.
Part of our sun & moon hub
Day Length Calculator sits in the sun & moon cluster, alongside 27 other tools that answer neighbouring questions with different methods or datasets.
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