# Roof Panel Footprint Planner

Fit modules into an entered rectangular usable area in two orientations.

[Open this tool](https://whatson.pk/roof-calculator/)

Category: Solar & Battery

A roof panel count needs a usable rectangle after access and setbacks, rather than the building's full footprint.

Enter module dimensions and the measured available area. Compare both orientations before planning tilt rows, shadows and structural requirements.

## Inputs and controls

* Usable roof length (m). Allowed range: 0.01 to 10000
* Usable roof width (m). Allowed range: 0.01 to 10000
* Module length (m). Allowed range: 0.01 to 20
* Module width (m). Allowed range: 0.01 to 20
* Clear gap between modules (m). Allowed range: 0 to 10
* Module power (W). Allowed range: 0.01 to 10000

## How to use

* Enter usable roof length and usable roof width.

* Enter module length, module width, clear gap between modules and module power.

* Select Calculate result. Read the returned values alongside the assumptions below before copying, exporting or acting on the result.


## Why use this tool

The orientation comparison gives a clear footprint check without implying that the larger fit is the approved layout.


## Before relying on the result

Flat rectangular footprint only. Define usable area after setbacks and access. Tilt rows, shadows, structure, fire access and wind loads need a site design. The larger fit is not structural approval.


## Tool limitations

Flat rectangular footprint only. Define usable area after setbacks and access. Tilt rows, shadows, structure, fire access and wind loads need a site design. The larger fit is not structural approval.

## Questions

### Does the fit prove the roof can support the panels?

No. Structure, wind loads, fire access and installation details require a site design.

### What should I check before using Roof Panel Footprint Planner?

Check Usable roof length, Usable roof width, Module length and Module width. Use the exact units shown beside the controls and replace any example values with your own inputs.

Source page last modified (UTC): 2026-10-01T18:56:36+00:00

This profile describes the tool. It does not execute it or supply a professional certification.