Free calculators for your website

Add a mortgage, cap rate or DSCR calculator to your site, blog or app for free. Copy the code below and paste it where you want the calculator. It resizes itself, works on phones, follows light and dark mode, and has no ads or lender buttons inside. Please keep the credit link under it.

Mortgage Calculator

Embed code

<iframe src="https://realestatecalculator.org/embed/mortgage" title="Mortgage Calculator" loading="lazy" style="width:100%;max-width:640px;height:760px;border:0" data-rec-embed></iframe>
<p style="font:13px/1.4 sans-serif;margin:4px 0 0">Mortgage Calculator by <a href="https://realestatecalculator.org/">RealEstateCalculator.org</a></p>
<script>addEventListener("message",function(e){if(e.origin!=="https://realestatecalculator.org")return;document.querySelectorAll("iframe[data-rec-embed]").forEach(function(f){if(f.contentWindow===e.source&&e.data&&e.data.recHeight)f.style.height=e.data.recHeight+"px"})})</script>

Cap Rate Calculator

Embed code

<iframe src="https://realestatecalculator.org/embed/cap-rate" title="Cap Rate Calculator" loading="lazy" style="width:100%;max-width:640px;height:520px;border:0" data-rec-embed></iframe>
<p style="font:13px/1.4 sans-serif;margin:4px 0 0">Cap Rate Calculator by <a href="https://realestatecalculator.org/cap-rate-calculator">RealEstateCalculator.org</a></p>
<script>addEventListener("message",function(e){if(e.origin!=="https://realestatecalculator.org")return;document.querySelectorAll("iframe[data-rec-embed]").forEach(function(f){if(f.contentWindow===e.source&&e.data&&e.data.recHeight)f.style.height=e.data.recHeight+"px"})})</script>

DSCR Calculator

Embed code

<iframe src="https://realestatecalculator.org/embed/dscr" title="DSCR Calculator" loading="lazy" style="width:100%;max-width:640px;height:700px;border:0" data-rec-embed></iframe>
<p style="font:13px/1.4 sans-serif;margin:4px 0 0">DSCR Calculator by <a href="https://realestatecalculator.org/dscr-calculator">RealEstateCalculator.org</a></p>
<script>addEventListener("message",function(e){if(e.origin!=="https://realestatecalculator.org")return;document.querySelectorAll("iframe[data-rec-embed]").forEach(function(f){if(f.contentWindow===e.source&&e.data&&e.data.recHeight)f.style.height=e.data.recHeight+"px"})})</script>

Building an app?

The math behind every calculator on this site lives in one small, typed, dependency-free TypeScript package with automated tests: mortgage payments with PMI, FHA, VA and USDA rules, amortization, refinance break-even, affordability, payoff, home equity and HELOC payments, rent vs. buy, and rental analysis (NOI, cap rate, cash-on-cash, DSCR, BRRRR and fix-and-flip). We're preparing it for public release under the MIT license. Want early access? Contact us.

import { mortgageEstimate, rentalAnalysis } from '@realestatecalculator/core';

const m = mortgageEstimate({ price: 400000, down: 40000, rate: 6.5, years: 30,
  taxYear: 4400, insYear: 1800, pmiPct: 0.5 });
m.total;      // 2942.11 — monthly payment including tax, insurance and PMI
m.pmiEndN;    // 110 — first payment without PMI

const r = rentalAnalysis({ price: 300000, downPct: 25, rate: 7.5, years: 30,
  rentMonthly: 2700, vacancyPct: 5, taxYear: 3600, insuranceYear: 1500 });
r.dscr;       // lender-style DSCR (rent ÷ PITIA)

Every formula is documented on our methodology page.