Can I add a calculator to my website that collects the visitor's email?

Yes, the AI can build it.

For a simple calculator, such as a mortgage or affordability calculator, build it directly on your website. Give the AI the list of questions or fields and the formula, and tell it when to change values, for example a price per square foot.

To capture leads, ask for name and email at the start, or ask for the email at the end before showing the results.

1. Create a form with just the email field (and name if you want it).
2. Give the AI that form's integration (the form endpoint), so the calculator posts each entry to your account and you get a lead.
3. Put those contacts in a drip campaign of a few emails.

If you need app-like behavior, such as logins where people save and review past calculations, build a Web App instead, because it has its own database and custom code.