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Solar Panel Spacing Calculator

Calculate the row spacing needed to avoid inter-row shading.

About Solar Panel Spacing Calculator

Row spacing must clear the shadow cast at the lowest useful sun angle, which occurs near the winter solstice. Steeper tilts cast longer shadows and therefore need wider spacing. There is a direct trade-off between tilt and density: shallower panels fit more rows in the same area, which often yields more total energy per hectare.

Formula

Solar Panel Spacing

Spacing = horizontal projection + panel height ÷ tan(winter solar altitude)

ground coverage ratio
Share of ground actually covered by panels
winter solar altitude
Lowest midday sun angle, around the winter solstice

Worked example

With the default values below, Solar Panel Spacing Calculator returns Minimum Row Spacing of 5.191. Change any input above and every figure here is recalculated in your browser.

Inputs used

Panel length along the slopeminimum 0.1 m
1.9 m
Tilt angleaccepts 0–90 degrees
30 degrees
Site latitudeaccepts -66–66 degrees
51.5 degrees
Available roof or ground lengthminimum 0 m
30 m

Results

Minimum Row Spacing
5.191 m
Vertical Height of the Tilted Panel
0.950 m
Winter Shadow Length
3.545 m
Rows That Fit in the Available Length
5
Ground Coverage Ratio
31.70%

Step by step

  1. 1Values used
  2. 2Solar Panel Spacing
  3. 3Minimum Row Spacing= 5.191 m
  4. 4Vertical Height of the Tilted Panel= 0.950 m
  5. 5Winter Shadow Length= 3.545 m
  6. 6Rows That Fit in the Available Length= 5
  7. 7Ground Coverage Ratio= 31.70

Assumptions and limits

  • The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is Solar Panel Spacing calculated?

Spacing = horizontal projection + panel height ÷ tan(winter solar altitude) Row spacing must clear the shadow cast at the lowest useful sun angle, which occurs near the winter solstice. Steeper tilts cast longer shadows and therefore need wider spacing.

Why does Solar Panel Spacing matter?

There is a direct trade-off between tilt and density: shallower panels fit more rows in the same area, which often yields more total energy per hectare.

What values do I need to enter?

This calculator takes 4 inputs: Panel length along the slope, Tilt angle, Site latitude, Available roof or ground length. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.

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