Built a free interactive mortgage calculator — drag sliders, see your numbers instantly. No ads, no paywalls

I built (vibe coded) [Hearth](http://hearth.emirpalace.ca) because I wanted to understand my mortgage better without spreadsheets or sketchy online calculators.

It's a **mortgage calculator** that actually makes sense. Just drag sliders: • Home price • Down payment • Interest • Term • Extra payments

See your full payment breakdown (principal vs interest), your amortization schedule, equity curve, and payoff date—all updating live as you move the sliders.

**What makes it different:** • Free. Forever. No ads, no paywalls, no subscriptions. • You own your data (it's all client-side if you want) • Run scenarios — compare different down payments, interest, extra payment strategies side-by-side • See exactly how much interest you save by paying extra • Works on mobile (sliders responsive, charts clean)

Built this for myself and friends. Figure someone here might find it useful too.

Bookmark it if you find it useful—feedback always welcome.