Calctoolz is a collection of free calculators for construction and home improvement projects, covering roofing, drywall, painting, and flooring. Our goal is simple: give you a result you can trust, along with the formula behind it.
How our calculators are made
Every calculator starts with research. Before writing any code, I look up the formula, standard, or specification in the original source, such as manufacturer guidance and official construction references, rather than copying it from other websites. Then I implement that logic in the calculator exactly as the source defines it. Each calculator page explains the formula it uses, so you can follow the math and verify it yourself.
About the founder
I’m Shivam, a software engineer and the founder of Calctoolz. I build and maintain every calculator on this site. My background is in software, which is why I focus on correct logic and clear, fast tools. You can find me on LinkedIn.
A note on accuracy
Calculators give estimates for planning your project. Real projects vary with site conditions, local codes, and material differences, so please read our Disclaimer and confirm important details with a qualified professional.