Calculateur de Mortgage
Estimate principal and interest mortgage payment.
Formula and method
This calculator computes Loan amount, Monthly principal and interest directly in your browser without sending data to an external server.
Mathematical formula
- Loan amount:
homePrice<down ? NaN : homePrice-down - Monthly principal and interest:
(() => { if(homePrice<down) return NaN; const principal=homePrice-down; const r=rate ÷ 1200; const n=years × 12; if (r===0) return principal ÷ n; const pow=1+r^(n); return !Number.isFinite(pow) ? principal × r : (principal × r × pow) ÷ (pow-1); })()
Variables and parameters
- Home price (homePrice): default value 400000 $.
- Down payment (down): default value 80000 $.
- APR (rate): default value 6.5 %.
- Term (years): default value 30 years.
Some formulas are undefined for certain input combinations (such as division by zero or logarithms of non-positive numbers). In those cases the live tool displays an alert instead of NaN.
Embed this tool
Paste this snippet into your own site or blog post to embed a live, working copy of this tool. It links back to the full page on SpecWhale.
Frequently asked questions
What equation and variables does Mortgage Calculator use?
Mortgage Calculator evaluates outputs such as <strong>Loan amount, Monthly principal and interest</strong> based on inputs including Home price, Down payment, APR, Term. Check the Mathematical Method section for the explicit formula.
How can I compare different financial scenarios using Mortgage Calculator?
You can click the "Add to Compare" button after computing your scenario to pin it to your temporary side-by-side Compare Workbench, allowing you to evaluate loan, rate, or interest differences.
What happens if I enter invalid or zero values into Mortgage Calculator?
If an input combination is mathematically undefined (such as division by zero or negative square roots), SpecWhale alerts you gracefully rather than returning invalid NaN outputs.
Are my calculations in Mortgage Calculator saved or private?
All calculations are 100% private and run locally in your Web browser. Your numbers are never uploaded to any server, but can be saved locally to your device or exported as CSV/JSON.
Is Mortgage Calculator free to use?
Yes. Mortgage Calculator is completely free, has no usage limit, and does not require an account, email, or API key.
Does Mortgage Calculator store or upload my data?
No. Mortgage Calculator calculates everything locally in your browser. Nothing you type is sent to a server or stored by SpecWhale.
How accurate is Mortgage Calculator?
Mortgage Calculator uses a standard formula (see the Method section above for the exact expression). For high-stakes financial, medical, or legal decisions, confirm the result with a professional or an authoritative source before relying on it.
Can I embed Mortgage Calculator on my own website?
Yes. Use the "Embed this tool" snippet on this page to add a free, working copy of Mortgage Calculator to your own blog post or page.