SubcontractorHub's BOM Calculator helps you estimate costs for materials and services across your solar projects, including soft costs. It not only improves accuracy in planning but also streamlines procurement with built-in approval workflows. Follow the steps below to create BOM formulae and templates for use in projects.
Step 1: Locate "Manage Database" and click "Database" from your SubcontractorHub menu list on the left.
Step 2: Scroll down your database list, select "BOM", and click on the "BOM Formulae" option
Step 3: Click "Add" on the top right corner to create a new BOM Formula
Step 4: Define Your Formula
This is the most critical step where you tell the system how to calculate the quantity of a material you want to include in your BOM.
You will see two main input areas:
Material: Choose the item (e.g. Inverter, Rails, Cement, etc.)
Formula: Use variables (Operands) and mathematical signs (Operators) to define how much material is needed.
Note: A formula is a calculation that tells the system how much quantity to use based on project-specific values.
For example: If you are building a house and want to order cement, you won’t just buy a random quantity, you would calculate how many rooms are being built, the size of each, and use a formula to determine the total cement required.
In solar, it’s the same. If you are ordering an inverter, you might base its quantity on the number of panels or arrays.
Here’s the formula building blocks:
Operands (the variables you can use):
These are the project-specific values the system already knows. Here's the list:
no_of_panels – Number of solar panels
no_of_arrays – Number of arrays
number_of_rows – Number of panel rows
panel_width – Width of a panel (in mm/inches)
panel_size – Total area of one panel
panels_per_row – Panels used per row
rail_length – Total length of rail per panel/row
manual – You can enter your own fixed number
Operators (math symbols to define the formula):
These allow you to calculate based on logic. Choose from:
+ (Addition)
- (Subtraction)
* (Multiplication)
/ (Division)
% (Percentage)
Here are a few examples explaining this further:
1. Let’s say you are ordering rails, and you want 1 rail per panel. Then your formula will be:
2. If you are ordering junction boxes, say one per array, your formula could be:
3. If your material requirement is based on a combination (like inverter based on panels and arrays), then you can build:
Once you have created the formula, the Formula Equation preview below the input will show how it looks logically.
Step 5: Click "Save" to set your new BOM Formula.
Step 6: Go back to the database list, select BOM, and click on the "BOM Template" option.
Step 7: Click "Add" on the top right corner to create a new BOM template.
Step 8: Fill up the necessary fields for your new BOM template and click "Save"
Step 9: After clicking on Save, you will be directed to the "BOM Template Detail" page to add your materials.
Step 10: Click "Add Material", and for each item, select:
The material
Quantity type (Formula or Manual)
If Formula → select the one you created earlier.
Step 11: Scroll up, and click on the "Update" button to create a new BOM Template.