Mortgage Calculator for Loan Officers

Try it yourself

This is a real, working CalcForms calculator, right here on the page. Enter your details and watch the estimate update on the spot. It is exactly what your customers would use, and every submission reaches you as a lead.

forms.badabingapp.cc/mortgage-calculator

What your customer answers

The live form above asks for these, in this order.

Their email, so the lead reaches you
Home price: a number
Down payment: a number
Interest rate %: a number
Loan term: 30 years, 15 years

What they see: Estimated monthly payment, worked out from their answers on the spot.

What it calculates

Shows principal, interest, taxes, insurance and PMI as one live monthly payment while the borrower types
Keeps your exact payment formula, property-tax and insurance factors and PMI rule from the spreadsheet you already price loans with
Captures every borrower as a pre-qualified lead with price, down payment, rate and term already attached
Update rate sheets, county tax tables or LLPA adjustments later just by asking ChatGPT, no rebuild
Run a few of your own past closings through the form so the quoted payment matches what you actually funded

Why it closes more deals

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A live number closes deals

Customers who see a real estimate the second they enter their details are far likelier to book than ones told to call for a quote. The number is the hook.

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Runs your most complex spreadsheet

Multi-tab workbooks, lookup tables, tiered rates, conditional line items, the lot. If the math runs in Excel, CalcForms runs it behind a clean form.

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Update it by chatting

Prices move. Ask ChatGPT to change a rate, add an option, or insert a step and the live form updates in seconds. No developer, no redeploy.

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Backtest before you publish

Run your last 20 real jobs through it and tune the formula until the live estimate matches what you actually charge. Ship it once it lines up.

Why calculator forms are worth it, by the numbers

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47.3% vs 2.8%

In an analysis of 50,000+ forms, interactive forms averaged a 47.3% conversion rate versus 2.8% for static forms. (Outgrow)

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51% of buyers

51% of B2B software buyers now begin their research in an AI chatbot rather than a search engine. (G2, 2026)

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1 in 3

A third of B2B buyers have chosen a vendor they had never heard of before, on an AI assistant's recommendation. (G2, 2026)

How this form was built

No template builder and no code. One message to ChatGPT with CalcForms added:

✦ ChatGPT with CalcForms

Build a mortgage calculator from my pricing workbook. Ask for home price, down payment, interest rate and a 30 or 15 year term. Run PMT on the loan amount, add property tax at 1.1 percent and insurance at 0.35 percent of the price per year, plus 0.7 percent PMI when the down payment is under 20 percent. Output one estimated monthly payment.

Done. I built Mortgage Calculator with your pricing and deployed it to forms.badabingapp.cc. Every submission is saved with the inputs, the results and the email. Want to add a field or change a rate? Just tell me.

Build this exact form

CalcForms is an app you add to ChatGPT once. After that you build and edit forms just by chatting. Works in Claude too.

Add CalcForms to ChatGPT. Open the CalcForms app page, click Install plugin, and sign in with your email. One time, about 60 seconds. A free ChatGPT account works. (Using Claude? Setup here.)
Say the words below. ChatGPT builds the form with your math inside and gives you a link.
Share it, then change it by asking. Send the link to customers. Change a rate or add a question later just by asking.

Step-by-step: turn your spreadsheet into a form, add your price list, show customers one number. All guides →

Say this to ChatGPT

"Build a mortgage calculator from my pricing workbook. Ask for home price, down payment, interest rate and a 30 or 15 year term. Run PMT on the loan amount, add property tax at 1.1 percent and insurance at 0.35 percent of the price per year, plus 0.7 percent PMI when the down payment is under 20 percent. Output one estimated monthly payment."

How does it work? CalcForms is an official ChatGPT app. Once it is added, ChatGPT can build, publish and update real calculator forms for you, all from the chat window. Your customers never need ChatGPT; they just open a link.

What it works out

Principal and interest
Property tax and insurance
PMI when needed
Total monthly payment

Last updated 6 October 2026

FAQ

Does it include taxes, insurance and PMI, not just principal and interest?

Yes. It returns full PITI. Property tax and insurance come from the factors in your sheet, and PMI is added automatically whenever the down payment is below 20 percent.

Can I keep the exact amortization math from my spreadsheet?

Yes. CalcForms preserves your real Excel payment and pricing logic across tabs, so the borrower sees the same payment your own workbook produces.

How do I update rates when the market moves?

Just ask ChatGPT. Tell it the new rate sheet or LLPA adjustments and the live form updates, no developer and no rebuild.

Build yours in the next 10 minutes.

Free in ChatGPT, unlimited forms and submissions. No credit card.

Add to ChatGPT, free →