How we calculate

Enter measurements in the units shown

Use the units printed beside each field. Check that the calculator’s shape matches your project. For product yield, density, or coverage, use information that matches the material and job conditions. Waste is not added unless a calculator says otherwise.

Understand rounding

Most results show up to three decimal places. The evaporation estimate shows up to six. Very small positive values use scientific notation; for example, 1e-6 means 0.000001. Bag and mesh-sheet counts round up to whole units. Use the unrounded value when entering a result into another calculation.

Use the examples

Select Load example to fill in sample values and calculate an example result. Select Reset to clear the fields. If you change an input, calculate again to update the result. Example values are for illustration; they are not defaults or recommendations for your project.

How calculations are checked

Calculations are checked against worked examples, unit conversions, and invalid or boundary inputs. These checks confirm the arithmetic covered by those tests. They do not approve a design or turn an estimate into a construction specification.

Use the calculators

Calculations run in your browser, so JavaScript must be enabled to calculate. Formulas, units, notes, and guides remain available without JavaScript. You can use the forms with a keyboard; errors identify the fields that need attention.

• Understand the estimating limits
• Choose a calculator