# Formulas

Use formulas in the calculator to convert from one unit to another. You can use the formulas supplied and you can create your own. For example, you can create formulas to convert from cubic yards (CY) to truckloads. The ratio of cubic yards to truckloads depends on the formula. You can add as many formulas as you want. See Calculator for details on using a formula.

The current quantity is represented in formulas as WT(). For more detailed information on formula logic, see the Using Math Operators and Using Math Expressions section.

You can create custom formulas that prompt you to enter additional values and define formulas based on the entered values and the working total. For example, you could create a formula to determine the square feet of dry wall needed based on the length of the wall in the Takeoff and the height you enter. For example, you could create a formula that converts from square feet (SF) to cubic yards (CY) by prompting you to enter a length to complete the conversion.

The spreadsheet portion of the Edit Formula pop-up window contains a series of columns that are labeled with letters and rows that are labeled with numbers. The cells within the spreadsheet are designated by their location. For example, the cell located in column A on row 3 is referred to as cell A3 (no spaces) in formulas.

The gray spreadsheet cells are text cells that cannot be used in formulas. When building a multi-step formula, enter the text of the question(s) that you want to be prompted to answer in these cells.

The white spreadsheet cells are formula cells. These cells are used to enter quantities to use in the formula. They are referenced as variables in the formula by their location B1, B2, B3, and so on. Enter 0 (zero) in a white cell to activate for use in a formula. You will specify the actual value when you use the formula.

You can change the color of a cell by clicking Toggle.

To open a job in the Manage Estimates screen, click OK.

in the All Tasks pane. Then select the job you want to open, and click## Example 1: Add a formula that converts a Working Total quantity from cubic feet to cubic yards

First, determine the unit of the Working Total to be converted and the unit of the result. In this case, you are converting square feet (SF) to cubic yards (CY).

In the Formula field, enter in the
conversion formula: `WT()/27` (no spaces). The formula takes the
current Working Total quantity (in Cubic Feet) and divides that by 27. The answer
becomes the new Working Total expressed in Cubic Yards.

After you have finished entering the conversion in the Formula field, click Test to test the formula.

Test calculates the formula using a default Working Total of 10.10. The formula you are testing is WT()/27, so the test returns:

`10.10/27 = 0.37
CY`

If the quantity calculated in the test mode does not equal the theoretical answer (in this case 0.37), then you need to review and adjust the formula.

## Example 2: Create a formula that calculates the volume of any common structural slab

First, determine the unit of the Working Total to be converted and the unit of the result. In this case, you are converting square feet (SF) to cubic yards (CY).

Select the gray cell at location A1 and type the following:

`Enter the thickness of the slab
(inches)`

Next, select the gray cell at location A2 and type the following:

`Enter waste factor
(percent)`

To activate the Formula cell next to each
question, select cell B1 and B2 respectively, and enter `0` into
each cell.

Now that you have entered the two question prompts and activated their formula cells, you can enter the math equation in the Formula field. To convert the current Working Total from square feet (SF) to cubic yards (CY), enter the following in the Formula field:

`(WT()*B1/12)/27*(B2/100+1)`

This formula takes the Working Total quantity WT() and multiplies it by the value entered in B1 (thickness of the slab in inches), then divides it by 12 to convert from inches to feet.

The resulting cubic foot quantity is then divided by 27 to convert it to cubic yards. This CY quantity is multiplied by the Waste factor entered in B2 to finish the calculation.

When you test this new custom formula, you are prompted to enter the thickness of the slab and the waste factor needed for the conversion. Enter a thickness of 12 inches and a waste factor of 7 percent, then click on the Cubic Yard field.

(10.10*12/12)/27*(7/100+1) = 0.4 CY