Disclaimer

Every calculator on this site gives an estimate from a standard formula and the numbers you enter. Results are for planning, learning and checking your own work.

• A result is only as good as its inputs and the formula’s assumptions. Real materials, conditions and measurements vary.
• Results are not professional advice. For building work, structural loads, electrical installations, chemistry outside a teaching lab, or anything where an error could cause harm or cost money, confirm the figures with a qualified professional and follow local codes and the manufacturer’s instructions.
• Quantities for materials (lumber, soil, gravel, paint) do not include waste unless the page says so. Add an allowance.
• The site does not give medical, legal, tax or financial advice.

If you think a result is wrong, please tell us through the contact page. See how the calculators work for rounding rules and limits.