Using the calculators
Keep measurements, units and quote scope consistent from the first input to the final estimate.
Choose the task you can measure
Start with a known dimension, package coverage or quoted rate. A roof footprint is a horizontal area; a sloped roof area follows the roof surface. A gutter run is a length. Use the tool that asks for the quantity you have.
Match every value to its unit
Read the unit beside each field before entering a value. Keep quantities and rates paired: square feet with dollars per square foot, or linear feet with dollars per linear foot. Available calculator pages start with an adjustable example and show its result. Replace these values with your measurements, product details or quoted rates, then calculate again. Reset restores the starting example.
State what a price includes
A dated national reference supports early planning. For a local quote, use the quoted rates and check whether labor, supplies, removal and disposal are already included. Add a separately priced item once; do not add it again when it is bundled into another rate.
Read the result and its rounding
A whole-package count rounds up when a partial package is still needed. A displayed dollar total may be rounded for readability. Read the formula and worked example on the tool page before combining a rounded output with another estimate.
Recognize the limits
Estimates do not replace product instructions, measured site conditions, a contractor quote or local requirements. A page marked “Planning guide” is a planning guide rather than an interactive result page. Use its preparation steps and related tools only within their stated scope.