Love the site. I enjoy negotiating a good lease deal almost as much as getting a new car!
I wrote a lease calculator for Android for my personal use, and over the years it evolved and I eventually made it available free on the Google Play Store: https://play.google.com/store/apps/details?id=com.rdl.rdlease
I invite suggestions, feedback, and constructive criticism on how I can improve the app. It’s not quite as fancy as the one here on this site, but it will give very accurate numbers if you enter all the data, or you can just enter the basics to get a rough approximation.
I hope this isn’t violating any site policies. Since it’s a free app (with no ads) I’m assuming it’s OK.