# Use formulas to calculate line item prices

Formulas help you calculate quantities for less common situations, such as the cubic yards of concrete in a trapezoidal wall or the number of shingles in a circular roof.

- Open an estimate.
- On the Estimate Items tab, click
**Items**. - Select a line item in the list below the Quick Entry pane.
- Click the
**Calculator**icon for Calc in the Quick Entry pane. - Click
**Formulas**to view a complete list of available formulas. - Select a formula, and enter the required information.
Click
**OK**.