To calculate the area of an irregular polygon is just like calculating the area of a triangle which is the formula of 1/2 bh (bxh) divided by 2

Other formulas I found is:

1. Break the polygon into triangles then add

2. Find missing triangles then subtract

3. Consider other shapes

4. If you know the coordinates of the vertices

For the full formula just visit:

Hope this helps you, thanks! :)