PITI and PMI math
Principal, interest, taxes, insurance, and PMI recalculated as buyers move the sliders, with an amortization summary.
The Problem
Buyers Leave to Do the Math Elsewhere
It happens on every listing page. A buyer sees the price, wonders about the monthly payment, and opens a bank's calculator in a new tab.
01 · Tab switching
Buyers open a bank's calculator in another tab.
The payment math lives on your listing page, so buyers stay.
02 · Partial math
Bank calculators show principal and interest, without taxes or insurance.
Taxes, insurance, HOA dues, and PMI show in one breakdown.
03 · Surprise payments
The payment looks affordable until the lender's estimate arrives.
Price, annual tax, and HOA fees fill in from your listing feed.
04 · Anonymous buyers
Buyers leave before you get their names.
Email-my-estimate and lender-call buttons capture details when buyers ask.
A buyer likes your listing and wants to know the monthly cost. Your page doesn't say, so they open a bank's calculator in another tab. It shows principal and interest only, without taxes, insurance, PMI, or the HOA fee. The number looks affordable until the lender's estimate arrives. By then the buyer is browsing someone else's site, and you didn't get their name.
We start with the math your buyers need: principal and interest, property tax, homeowners insurance, HOA dues, and PMI when the down payment is under 20%. On listing pages, it can pull price, tax, and HOA figures from your feed and let buyers adjust the rest. When they want the numbers emailed or a call from your lender partner, you get the lead. Buyers stay on your page, not a bank's.
The full monthly payment
Principal, interest, taxes, insurance, PMI, and HOA dues in one breakdown buyers can read.
Prefilled from your listings
Price, annual tax, and the HOA fee come straight from your IDX or RESO Web API feed.
Leads when buyers ask
Email-my-estimate and lender-call buttons capture the buyer's details at the right moment.
Our Calculator Build Process
From Loan Defaults to Your First Emailed Estimate in Five Steps
You approve the defaults, the disclosure text, and the design before launch. Your lender partner's compliance team signs off on anything that shows rates or payments.
We look at your listing pages, your IDX provider, and any lender partnership. You get a recommendation on calculators, defaults, and lead routing, plus a fixed price for the whole build.
What's Included
What You Get With Mortgage Calculators for Websites
Everything a buyer needs to judge a payment on your page: the math, the data, the design, and a way to reach you when they're ready.
Compare Options
DeveloperLook vs Free Calculator Widgets vs Lender-Provided Calculators
Free widgets cost nothing, and lender calculators come with rate data. Here's where each fits on an agent or broker site, and where each falls short.
| Feature | DeveloperLookBest fit | Free calculator widget | Lender-provided calculator |
|---|---|---|---|
| Payment breakdown | Full PITI plus PMI and dues | Often principal and interest | Varies by lender |
| Listing prefill | Price, tax, and dues filled in | Typed in by the buyer | Rarely tied to listings |
| Brand control | Your brand throughout | Provider's logo or link | Lender branding |
| Where leads go | Your CRM, plus lender by opt-in | Nowhere, or the provider | Straight to that lender |
| Rate data | Defaults you or a lender set | Generic defaults | Current rates from the bank |
| Disclosure wording | Approved by the lender | A generic disclaimer | Handled by the lender |
| Time to launch | 1 to 5 weeks | A few minutes | Days, if offered |
| Upfront cost | From $650, fixed scope | Free to use | Often free for partners |
DeveloperLook
Free calculator widget
- Payment breakdown
- DeveloperLook: Full PITI plus PMI and duesFree calculator widget: Often principal and interest
- Listing prefill
- DeveloperLook: Price, tax, and dues filled inFree calculator widget: Typed in by the buyer
- Brand control
- DeveloperLook: Your brand throughoutFree calculator widget: Provider's logo or link
- Where leads go
- DeveloperLook: Your CRM, plus lender by opt-inFree calculator widget: Nowhere, or the provider
- Rate data
- DeveloperLook: Defaults you or a lender setFree calculator widget: Generic defaults
- Disclosure wording
- DeveloperLook: Approved by the lenderFree calculator widget: A generic disclaimer
- Time to launch
- DeveloperLook: 1 to 5 weeksFree calculator widget: A few minutes
- Upfront cost
- DeveloperLook: From $650, fixed scopeFree calculator widget: Free to use
Projects We've Built
Finance and Property Sites We Have Built
Finance and property websites from our portfolio. A calculator sits on sites like these as a listing section, a standalone page, or an embed.
Envitis Investment Website Design & Development
- Finance
- Dashboard
- Website
Finto Corporate Website Design & Development
- Finance
- Dashboard
- Website
DWLFNDR Real Estate Website
- Real Estate
- Dashboard
- Website
HavenHues Real Estate Website
- Real Estate
- Dashboard
- Website
What Our Clients Say
What Clients Say After Launch
Feedback from teams we have built websites and calculators for.
We had a pretty specific idea of what we wanted our website to become, but I wasn’t sure how easily we could explain all of it to a development team. There were quite a few moving parts, and we were working toward a deadline, so I expected a few things to get lost along the way. That never really happened. They understood what we were trying to achieve, kept us updated throughout the process, and got everything ready within the agreed timeline. The final site feels much easier to navigate, works beautifully on mobile, and is noticeably smoother for our customers. It was a huge relief seeing the original idea actually turn into the website we had in mind.
The mobile experience is probably my favourite part of the new site. We had spent a lot of time making sure the desktop version looked right, and the team kept pushing us to think about how everything would actually feel on a phone too. They were right. The navigation is clean, the interactions feel natural, and everything we’ve tested so far works exactly as it should. They also went through the links, forms, integrations, and other details more than once before launch, which I really appreciated. And even after going live, we could still reach out when something came up. The whole process felt friendly, organised, and surprisingly straightforward.
What I appreciate most is that the website is actually easy for us to manage now. We can update content ourselves instead of sending a developer a message every time we need to change something small. They also paid attention to the technical SEO side, which mattered to us because we didn’t want a new website to create problems for the traffic we already had. I’ve probably asked more questions than I should have since launch, but every question has been handled patiently and without any fuss. The team is easy to work with, they explain things clearly, and when we need something changed, they focus on getting it done rather than making the process complicated.
1,250+
Projects shipped
10+
Years of experience
Top 3%
Upwork Top Rated Plus
5 stars
Average review score
Want results like these?
Tell us what you are building. You get a reply within 24 hours on business days, then a written estimate.
Work Culture
Why Brokers Trust Our Payment Math
A payment calculator is only useful if the number holds up when the loan estimate arrives. These habits keep yours accurate, compliant, and easy to trust.
Math checked against lenders
Before launch, we compare the calculator's results with a loan officer's own figures for several loan scenarios. A payment that's off by a few dollars makes buyers doubt everything else.
Defaults you control
You or your loan partner set default rates, terms, and PMI factors in an admin panel. The calculator shows only numbers you have approved.
Disclosures before launch
If the calculator displays a rate or sample payment, your lender's compliance team approves the wording first. Regulation Z's advertising rules can apply, so we don't guess.
Tested on real phones
Buyers run numbers on their phones while touring homes. We test sliders, keyboards, and screen readers on real devices before launch.
You own the calculator
The calculator's code, settings, and embed are yours from launch day. Move sites or agencies, and your calculator moves with you.
A fixed price before we start
You get a written scope and a fixed price before any code is written. Changes are priced before they're made, not after.
Overview
Who builds a custom mortgage calculator for website listing pages?
DeveloperLook builds a mortgage calculator for website listing pages, loan officer sites, and brokerages. Every build shows principal, interest, taxes, insurance, PMI, and association dues, and sends leads to your CRM. Larger builds prefill listing data and add a lender handoff. Builds start at $650, most go live in 1 to 5 weeks, and you own the code.
DEVELOPERLOOK
Project facts · Mortgage Calculator Development for Websites
- Service
- Mortgage payment calculators (PITI, PMI, leads)
- Typical timeline
- 1 to 5 weeks, by plan
- Platforms
- WordPress, Webflow, Next.js, or any site
- Built with
- React, TypeScript, RESO Web API, CRM APIs
- Experience
- 10+ years of development experience and 1,250+ shipped projects
- Post-launch support
- 30, 60, or 90 days, by plan
- Communication
- Calls in US, UK, and AU business hours
- Starting price
- From $650 USD, fixed scope after discovery
Reviewed 28 Sep 2026 by Saimul Islam
Good fit
Agents with bare listing pages
Your listing pages show a price and nothing else. Buyers leave to run the numbers on a bank's calculator and don't come back.
Loan officers and mortgage brokers
You want a mortgage calculator for website visitors that carries your brand and captures their details. Generic widgets show another company's logo instead.
Brokerages with lender partners
Your brokerage works with a preferred lender. You want listings to show a payment and offer a lender introduction the way your compliance team approves.
Teams whose buyers underestimate costs
Your buyers budget on principal and interest alone, then balk at taxes, insurance, PMI, and association dues. You want the full payment shown up front.
Agencies building realtor sites
Your agency needs calculators for several realtor and lender clients. You want one tested build you can restyle, embed, and support under your brand.
Not a fit
Live rates or approvals
You need live rate quotes or loan approvals online. That's a lender's application system, while our calculator estimates payments and hands buyers to your lender.
Free widget will do
Your budget is under $650 and a free widget will do. A free calculator is a cheaper start, though it usually carries the provider's branding, and we'll say so.
Owner valuation leads
Your goal is listings, not buyers, and you want owners asking what their home is worth. Our Home Valuation Lead Magnet Development page covers that tool.
Buyer ad campaigns
You want campaigns that bring more buyers to your listings each month. Our Real Estate Lead Generation Services program runs those campaigns for you.
Not sure we're the right fit?
Book a free call or message us. We'll tell you honestly whether we're the right team.
Pricing
Transparent Starting Prices for Payment Calculators
These are starting points in USD. Your final price depends on how many calculators you need, listing prefill, and lender links, and you get a fixed proposal after a free calculator review.
For agents and brokers who want one payment calculator on their own site.
$650one-time, USD
- PITI payment math with PMI and HOA dues
- Styled to your brand, built for phones
- Embed on your listing template or any page
- Email-my-estimate lead capture
- Leads sent to your CRM
- 30 days of post-launch support
Recommended
For teams that want payments prefilled on every listing and a lender handoff.
$1,550one-time, USD
- Everything in Branded Calculator
- Price, tax, and dues prefilled from your feed
- Home affordability calculator
- Lender partner card with approved disclosures
- Leads routed to agent and lender
- 60 days of post-launch support
For lenders and brokerages that need several calculators and admin control.
$3,200one-time, USD
- Everything in Listing Payment Suite
- Refinance and rent-versus-buy calculators
- Admin panel for rates, terms, and PMI factors
- Branding per agent or branch
- Lender rate feed, where available
- 90 days of post-launch support
For Agencies
White-Label Calculators for Agencies With Realtor and Lender Clients
You own the client relationship. We build the calculator, connect the listing feed, and set up lead routing under your brand. One tested build can be restyled for each realtor or lender client you add.
How the partnership works
White label: your client only ever sees your brand
- Your client
- You, the agency
- DeveloperLook
Share the brief
Send the client's site, listing feed, and lender details, and we reply with scope and price.
- Client needs
- You share the details
- Details received
We build and test
We build the math, the design, and the lead routing, then test all of it.
- Scope and plan
- Proposal to resell
- Your quoteYOUR LOGO
Launch and support
Your team launches it, and we stay on call for fixes during the support window.
- Done by our team
- Your brand on it
- Handed to your clientDone
Partner with DeveloperLookDelivered under your brand
Stay client-facing
Embeds, admin screens, and calls carry your agency's name.
Tested math
Formulas checked against lender figures before any client sees them.
Senior engineering
Developers who build web components that load fast on phones.
Flexible capacity
Add calculator clients without hiring another front-end developer.
The Right Technology for Your Project
Technology Stack
We build calculators as fast, accessible web components, feed them listing data, and send every lead to the CRM you already use.
React
TypeScript
JavaScript
Tailwind CSS
WordPress
Webflow
Next.js
Vercel
- RESO Web API
- IDX feed
Node.js
PostgreSQL
- Follow Up Boss
HubSpot
Google Analytics (GA4)
Google Tag Manager
FAQ
Frequently Asked Questions
Straight answers on cost, payment math, lender partners, disclosures, and branding for agents, brokers, and lenders.
Saimul IslamFounder & CEO, DeveloperLookStill have questions?
Send a message or book a call with the team.
Custom calculators start at $650 for one branded payment calculator with PITI math, PMI, and HOA dues. A listing suite with prefilled data, an affordability tool, and lender handoff is $1,550, and a multi-calculator platform for lenders starts at $3,200. You get a fixed proposal after the free calculator review.
A mortgage calculator for website listings usually goes live in 1 to 5 weeks. A single branded calculator takes about a week, and listing prefill with lender handoff takes 2 to 3 weeks. Multi-calculator platforms take 4 to 5. If your IDX provider limits custom scripts, we check the embed options first.
An embedded calculator answers the buyer's next question on your page instead of a bank's. An interactive real estate mortgage calculator keeps buyers adjusting down payments and terms on your listing, so visits last longer. The lead comes when they ask to email the breakdown or talk to a lender, a moment you'd otherwise miss.
The calculator recomputes every figure each time a buyer moves a slider. Principal and interest use the standard amortization formula on the loan amount, rate, and term. Annual tax and insurance are divided by 12, and HOA dues come from the listing. PMI usually applies to conventional loans with less than 20% down, using a factor the lender provides.
Yes, through a lender card, a rate feed, or a lead handoff to the lender's system. Co-marketing falls under RESPA Section 8, which bans referral fees but allows payment for services actually performed. So your broker and the lender's compliance team approve the setup, and we build what they approve.
We build the mortgage calculator widget for website pages as a web component that takes your fonts, colors, and spacing, so it looks native. Styles live in one place, so a rebrand is a quick change. It runs on WordPress, Webflow, Next.js, and IDX templates that allow custom scripts.
They often do when a rate or payment appears by default. Under Regulation Z, an ad that states a rate must show it as an annual percentage rate. A stated payment amount triggers disclosure of the down payment, repayment terms, and APR. So your lender sets any default rate and the disclosure text.
It follows the federal rules for conventional loans. Borrowers can ask to cancel PMI when the balance is scheduled to reach 80% of the home's original value, and servicers must end it at 78%. The amortization view marks the month PMI drops off, so buyers see the full picture.
They go to your CRM, your lender partner, or both, based on what the buyer asks for. Email-my-estimate requests reach your CRM as buyer inquiries with the listing and payment attached. Lender calls go to the lender only when the buyer opts in on the form.
You own the code, the settings, and the embed from launch day. It runs on your site or your hosting, with no per-view fees from us. Support lasts 30, 60, or 90 days by plan, and any later changes are quoted in writing before we start.
Saimul IslamFounder & CEO, DeveloperLookStill have questions?
Send a message or book a call with the team.
Free 30-min callGoogle Meet
Book a call
Book a free 30-minute call
In 30 minutes on Google Meet we walk you through how we would build it, how long it takes and what it costs. Then you get a written estimate.
Calendar not showing? Book on cal.com or send a brief.