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Shadow & Solar Analysis Calculators

Professional solar geometry tools for sun angle, shadow length, solar window, and daylight hours. Optimise pergola orientation, tree placement, and shade structure design for any latitude.

Location & Time
Positive = N, negative = S
Set to your local timezone offset including DST
Solar Altitude / Elevation
–
°
Solar Azimuth
–
° from North
Solar Declination
–
°
Hour Angle
–
°
Solar Noon
–
local time
Sunrise
–
local time
Sunset
–
local time
Sun Status
–
Monthly Solar Summary
MonthSunriseSunsetDaylengthSolar Noon Altitude
NOAA Solar Position Algorithm (Meeus 1998 simplified): Declination δ = 23.45°×sin(360/365×(day−81)). Hour angle H = 15°×(localSolarTime−12). Altitude = asin(sin(lat)sin(δ)+cos(lat)cos(δ)cos(H)). Azimuth derived from spherical trigonometry, measured clockwise from North.
Object & Sun Geometry
Auto from Tab 1 or enter manually
Auto from Tab 1 or enter manually
Positive = ground slopes toward the sun (reduces shadow)
For overlap check across a row
Horizontal Shadow Length
–
m
Slope-Corrected Length
–
m
Shadow Direction
–
° from North
X Offset (East-West)
–
m
Y Offset (North-South)
–
m
Shadow Area (elliptical approx.)
–
m²
Overlap Check
Shadow length L = height / tan(altitude). If altitude ≤ 0°, shadow is infinite (sun below horizon — no shadow cast in normal sense). Slope correction: L_slope = L × cos(slope)/cos(altitude-slope) approximated for slopes facing the sun.
Pergola Geometry
Assessment Time
Auto from Tab 1
Auto from Tab 1
Floor Area
–
m²
% Shaded at Solar Noon
–
%
% Shaded at 09:00
–
%
% Shaded at 15:00
–
%
Slat Shadow Ratio
–
ratio
Annual Shaded Hours (est.)
–
hrs/yr
Glare Reduction Estimate
Hourly Shadow Profile
TimeSolar AltitudeSolar Azimuth% Floor Shaded
Slat shadow projects onto the floor based on solar altitude and the angle between rafter direction and solar azimuth. % shaded = slat_width / (slat_width + gap) when sun is perpendicular to rafters; reduces toward 0% when sun is parallel to rafters. CIBSE AM11 recommends 50–70% shading for comfortable outdoor seating in summer.
Tree Specification
Auto from Tab 1
Auto from Tab 1
Growth Projection
Shadow Length — Current
–
m
Shadow Area — Current
–
m²
Shadow Length — Target Year
–
m
Canopy Spread — Target Year
–
m
% Ground Shaded — Current (noon)
–
%
% Ground Shaded — Target (noon)
–
%
Neighbouring Property Encroachment
–
m
Growth Status
Shadow length and canopy area are projected based on linear annual growth rates until canopy spread reaches a typical mature maximum. Consider seasonal variation: this projection uses the entered solar altitude (typically representative of a single assessment date — repeat for summer/winter solstice for full annual picture).
Site Orientation
Direction the main facade faces
Auto from Tab 1
Obstructions
Hours Unobstructed — Summer Solstice
–
hrs
Hours Unobstructed — Equinox
–
hrs
Hours Unobstructed — Winter Solstice
–
hrs
Vertical Sky Component (VSC) Estimate
–
%
BRE 209 No-Sky Line Assessment
BRE 209 (2022) Site Layout Planning for Daylight and Sunlight: gardens and amenity spaces should receive at least 2 hours of sunlight on 21 March (equinox) to at least 50% of their area, ideally more. VSC <27% may indicate insufficient daylight to a window. This tool provides an indicative obstruction analysis — full assessments require 3D modelling software.
Location & Date
Auto from Tab 1
Daylength
–
hrs : min
Sunrise
–
local time
Sunset
–
local time
Solar Noon
–
local time
Peak Solar Altitude
–
°
Civil Twilight Dawn
–
local time
Civil Twilight Dusk
–
local time
Golden Hour Duration
–
min
Summer Solstice
–
Equinox
–
Winter Solstice
–
Annual Daylength Summary
MonthSunriseSunsetDaylengthPeak Altitude
Twilight angles: civil (0–6° below horizon, enough light for outdoor activity), nautical (6–12°, horizon visible at sea), astronomical (12–18°, full darkness for astronomy). Golden hour ≈ period when solar altitude is between 0° and 6°, producing warm directional light favoured for photography and landscape lighting design.

CalcType: Professional Solar Geometry & Shade Analysis Solutions — This advanced sun and shadow analysis suite is engineered to support evidence-based shading strategy and microclimate design for landscape architects, urban designers, and site planners. Utilising internationally recognised solar geometry algorithms based on the NOAA Solar Calculator (Spencer 1971) and astronomical declination models, the platform calculates precise solar altitude and azimuth angles for any global latitude, enabling accurate shadow casting for vertical objects, overhead structures, and tree canopies. The Pergola & Overhead module factors in rafter geometry and slat opacity to determine seasonal floor coverage, while the Tree Shadow module projects crown ellipses based on height, spread, and canopy density. The Solar Window tool quantifies site obstructions and validates horticultural sun exposure requirements (full sun, part shade, full shade) in accordance with standard planting guidelines. Daylight Hours calculations support seasonal planting schedules, lighting design trigger times, and biodiversity planning. Whether you are siting a shade sail for summer comfort, positioning specimen trees to protect south-facing façades, or validating sun access for rooftop gardens, CalcType provides the technical rigour required for microclimate-responsive, evidence-based site design. Technical Disclaimer: The solar geometry data and shadow projections provided by this calculator are intended for preliminary estimation and schematic design purposes only; all final shading analyses, daylight assessments, and solar access studies must be verified using licensed sun-path simulation software (e.g. NOAA Sun Calculator, Ladybug/Honeybee, Ecotect, or HelioScope) and validated by a qualified landscape architect, environmental designer, or solar engineer prior to construction or planning submission. Actual shadow patterns may vary due to terrain topography, atmospheric conditions, reflectance, and Daylight Saving Time adjustments; therefore, CalcType assumes no liability for thermal comfort failures, planting losses due to incorrect sun exposure assessment, or regulatory non-compliance resulting from the use of these tools.