ShadowCalc: Sun Shadow Length

TipTinker

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About this app

ShadowCalc works out how long a shadow an object casts at a chosen place and moment, and works backwards from a measured shadow to the object's height. Handy for photographers, garden and patio planning, solar siting, architecture sketches and science class.

• Shadow length from object height, place, date and time
• Measure height: type a shadow length and get the object's height, with a ±1° sun-angle range
• Enter latitude and longitude, or fill them in with your current location
• Sun elevation and azimuth from true north, plus the direction the shadow points
• Read the time in UTC, your device zone, or any zone ID or offset, with daylight saving handled
• Sunrise, sunset, solar noon and golden hour for the chosen date
• Shadow by time: a 15, 30 or 60 minute table you can copy
• A daylight curve of shadow length with solar noon marked as the shortest
• Height presets for a person, a building story, a flagpole or a streetlight
• Meters or feet; typed values convert when you switch
• A clear No Shadow result when the sun is below the horizon; polar day and night are handled
• Save scenarios with notes, load and update them later, and share a result

Sun position follows the NOAA solar equations and includes standard atmospheric refraction. Azimuth is measured from true north.

Official sources:
• NOAA Solar Calculator, calculation details: https://gml.noaa.gov/grad/solcalc/calcdetails.html
• NOAA improved sunrise/sunset calculation: https://gml.noaa.gov/grad/solcalc/sunrise.html
Not affiliated with or endorsed by any government agency.

What’s new

Performance improvements and bug fixes