We don't do anything unpleasant. You may stop reading here, most likely you won't find anything interesting down there, but if you read all the way to the bottom, you'll get a prize!
Providing a valuable service and solving your problems is our primary goal, doing nasty crap would go against this rule. Sometimes it's not clear whether something is cool or not (for example, we support the website with ads, and ad networks do track you), so just in case what we do might be interpreted as uncool, we'll list everything that might be suspicious below.
We are not collecting any personal data at the moment. We will once we'll have user accounts.
Our advertising partners (won't list them, as we're about to change them and they're pretty much the same evil) do all that's in their power to track you to provide more relevant ads. Personally, I kinda prefer seeing ads of things I'm interested in, but I do understand why other people feel uneasy about ad networks knowing so much about them.
We are using Google Analytics to collect data to understand our visitors better - which calculators you use, how you use them, what features you like, etc. To us, it's all anonymous data. To Google... well, they serve ads for a living, don't they?
We are not storing anything you input into calculators unless it's a rare situation when an error happens - in such a case we send everything you did with the calculator (entered 50 into "cost", then 25 into "margin", and so on). We use Sentry (a 3rd party service) to handle those error reports for us. They automatically store your IP address and the referrer (an address of the web page you came from), so theoretically we could use it to identify you somehow. But we don't. Making calculators is way more fun.
The general rule applies - be nice, we'll do our best as well.
Good job, you made it to the bottom. Now you get to watch these cute animals. I promise, in six minutes you'll barf a rainbow.