How to calculate retaining wall?

To calculate a retaining wall, you need to determine the following factors:
-The type of material used (e.g. concrete, stone, masonry, etc.)
-The size and shape of the wall
-The desired height of the wall
-The slope of the ground behind the wall
-The soil conditions
-The amount of water runoff the wall will need to resist
-Any additional structural considerations, such as tie-backs or reinforcing steel bars

Once you have determined these factors, you can then calculate the total amount of material needed for the wall, the cost of the materials and labor, and the estimated time for completion. You may also need to obtain a permit from your local building authority before starting the project.