Calctoolz is a collection of free online calculators, starting with construction and home improvement projects such as roofing, drywall, painting, and flooring, with more topics added over time. 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 or specification in the original source 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 check it yourself. If you find a result that looks wrong, I want to hear about it.
About the founder
I’m Shivam, a software engineer based in India 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 that work well on phones, tablets, and desktops.
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.
Get in touch
Found an error or want a new calculator? Email contact@calctoolz.com or visit our Contact page.