It is very simple to use


North America

(USA, Canada, Mexico...)


(All Europian countries)


Almost all countries

North Africa

All aboce equator

Solar Panel Angle Calculator (SPAC)

If you have decided to invest in solar panels and do not know where to start, then you are in the right place: The Solar Panel Angle Calculator (SPAC) calculates: the setting angle for fixed and tilting panels, obstacles (shadows from neighboring objects such as trees, houses, etc.) and the energy you can get. That doesn’t mean you won’t need advice or a project from solar installers, but you’ll have a pretty good starting point that no one will be able to scam you in the worst case scenario. You will also know (based on your roof orientation where you are placing the solar panel) what you can expect in terms of how much electricity you will get and thus the economic return.

All you have to do is to enter a few data about the object on which you are installing solar panels, namely: the latitude of the place where your object is located (or choose from the list of cities) you are planning, the orientation and the slope of the roof. For now, SPAC only considers the Northern Hemisphere: USA, Mexico, Canada, Europe and Asia. The potential of these locations is good due to their generally good sunny conditions, especially in the central US and southern Europe. Asia has great potential, especially for Arab, Middle Eastern countries, India, Indochina. It is very important that at least one part of the roof is facing south. If your roof  facing completely to the west or completely to the east, then the calculations of this application are not valid.
Roof faced on the north is out of question.

Two options

Roof or ground

Solar power plants

Small solar power plant located on the backyard or any unused land.

There are several variants in case you decide on a small solar power plant on ground.


Solar panel on roof house​

Solar panels on a roof that is at least partially facing south (south south-east or south-west)​ The ideal angle of a fixed panel on the roof or on ground – depending on the geographical location of your property.



The altitude angle is greater in summer than in winter, which means that the shadow is smaller. So we can say  the sun is lower in  winter than in summer. The shadow of surrounding objects is longer in winter than in summer. SPAC calculates the altitude and azimuth angles for each solar hour, so that we can calculate the length and position of the shadow of surrounding objects and possibly conclude whether and how much shadow will partially obscure the solar panel.

The harmful influence of surrounding objects

Trees, surrounding houses, or any nearby objects that exceed the level of the solar panel can have a harmful effect by casting a shadow, especially in winter.

Improper solar panels distance

If solar panels are placed too close to solar power plants, a shadow effect may occur, where one panel partially obscures the other

maximum efficiency

Following the sun

The solar panel does not have to be fixed, as I mentioned earlier. It is possible to adjust the panel so that the sun’s rays fall at an angle of approximately or exactly 90 degrees – to increase efficiency.

One axis tracker

Adjusting the panel by rotating around one axis is done depending on the day of the month or the month of the year. For this purpose, we need the altitude angle data that SPAC calculate by on the latitude of your installation location. This panel can stand completely horizontally in the case of cloudy weather when only the diffuse radiation component is used. Settings can be done manually or automatically.

Sun follow panel, two axis tracking

The sun follow panel has a much higher efficiency, but also a more complicated tracking system which requires rotation around the vertical axis depending on the time - the hour angle. The rest is similar as one axis adjustment system. So its adjusments depends from date and time and couldnt be done manualy.

how to

How to measure

The best solar panels in 2023

Best solar panels for residental use in 2023

Solar tutorial

SPAC tutorial.

SPAC aplication

How does the SPAC application work?.

Solar swindle ?

Impruving solar can be a swindle; pay attention to these facts.