Materials Calculator code

I need to insert code for a materials calculator. I can’t find any free code on the web. I need it to calculate length, width, and depth and include a reset button. I have a basic understanding of code. Any help would be much appreciated. Thanks

If you look on Vorbly site here - https://www.vorbly.com/vorbly-code - you will find a few examples of how to calculate things on your site with or without reset buttons.

Or there are online examples that you can learn from…
http://javascript-coder.com/javascript-form/javascript-calculator-script.phtml
https://www.webdeveloper.com/d/304659-how-to-create-price-calculator-for-html-website/2
https://www.geeksforgeeks.org/html-calculator/
https://codeburst.io/making-a-calculator-with-basic-html-css-and-javascript-part-1-1e4288f0bea1
https://jscalc.io/
https://ucalc.pro/en