Recently noticed that more and more different e-commerce sites began to use online calculators. At the same time, these are completely different businesses, from online stores to corporate sites with services. Earlier, I also saw that many people use calculators, but recently they seem to have become very popular. Of course, to create a calculator you need to at least be able to program. So it was before. But now I noticed that more and more different plugins for Wordpress and other systems began to appear, through which you can create and place an online calculator on the site. Moreover, various online calculator creation services began to appear, recently the builder of calculators uCalc recently found it. I went and looked at freelancing sites and various web studio sites and it turned out that they also provide calculator services. Are calculators really popular right now? Are they useful for e-commerce and why? What tools do you make online calculators?