01
Report a calculation issue
Include the calculator name, selected units, the inputs you used, the result you expected, and the result you saw. Do not include private or sensitive information.
02
Suggest a content correction
Include the page URL, the statement that needs review, and a primary source when available.
03
General feedback
Tell us which project you were planning and what would have made the tool easier to use.
Email channel
Email ivanfrogecn@gmail.com with the calculator name, inputs, and the result you saw. This address opens your email provider; the site does not store messages or project measurements.
Email the project teamBefore reporting a difference
Product labels and supplier package sizes can differ from planning defaults. The methodology explains what the calculator controls.
Check the methodology →Browse calculators →