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 lands in your dashboard as a lead.
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 rates and PMI lookup tables from the spreadsheet you already price loans with
- Captures every borrower as a pre-qualified lead with price, down payment, rate and DTI already calculated
- Update rate sheets, county tax tables or LLPA adjustments later just by asking ChatGPT, no rebuild
- Backtest the form against past closings so the quoted payment matches what you actually funded
Why it closes more deals
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.
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.
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.
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 convert — by the numbers
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)
2× conversions
Interactive content generates roughly twice as many conversions as static content. (Content Marketing Institute)
51% of buyers
51% of B2B software buyers now begin their research in an AI chatbot rather than a search engine. (G2, 2026)
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:
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 Add, 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 →
"Build a mortgage calculator from my pricing workbook. Use the PMT formula on the Amortization tab, pull property tax by state from the Tax Rates tab, and add PMI from the PMI lookup table when the down payment is under 20 percent. Output the full PITI payment."
Example run: A borrower enters a 450,000 dollar home with 90,000 down at 6.75 percent over 30 years. The form returns roughly 2,940 dollars per month PITI, then sends you the lead with their price, 20 percent down and DTI already calculated.
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
Monthly paymentProperty tax and insurancePMI when neededTotal interest
FAQ
Does it include taxes, insurance and PMI, not just principal and interest?
Can I keep the exact amortization math from my spreadsheet?
How do I update rates when the market moves?
Build yours in the next 10 minutes.
Your first form is free. No credit card.
Add to ChatGPT, free →