I built a mortgage payment calculator for people who just want clean, fast numbers without the lead-gen friction.

https://toolvault.co/tools/mortgage-payment-calculator

It started because every time I tried to run mortgage scenarios, I hit one of these problems:

Forms that demand email/phone before showing results

Slow, ad-heavy pages that feel like landing funnels, not tools

Calculators that only show principal + interest, ignoring real monthly costs

What this tool does:

Calculates full monthly housing cost: principal, interest, property tax, insurance, PMI, and HOA fees

Shows an amortization-style breakdown so you can see how payments shift from interest to principal over time

Lets you quickly tweak: home price, down payment, interest rate, loan term, and extra monthly costs

Works well on mobile and desktop, no account or email required

A few design decisions I made:

No popups, no dark patterns, no “talk to a lender” wall

Reasonable ad density only (I do monetize it, but tried hard not to make it miserable)

Defaults tuned for 2026-style rates but everything is editable

Things you can use it for:

“How much house can I realistically afford?” style scenarios

Comparing 15 vs 30 year terms and seeing total interest difference

Testing how much a bigger down payment really changes the monthly

Quick refinance what-ifs (set down payment to 0 and plug in your current balance + new rate)

I’m a solo dev working on a suite of small, focused tools, and this is one of them. The account posting this is ~20 days old with basically no karma, so I’m very open to blunt feedback on both the product and how I’m launching it.

I’d love feedback on:

Is the UX clear, or does anything feel confusing or distracting?

Are there any must-have inputs I’m missing (e.g. specific tax/insurance assumptions, regional quirks)?

Would you trust / actually use this when evaluating a home or refinance, and if not, what’s missing?

If this is useful to you, I’m happy to iterate based on your comments and ship improvements quickly.

Submissions

Show HN: Mortgage Payment Calculator (fast, no signup)

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