Show HN: Mortgage Payment Calculator (fast, no signup)(toolvault.co)
toolvault.co
Show HN: Mortgage Payment Calculator (fast, no signup)
https://toolvault.co/tools/mortgage-payment-calculator
1 comments
I appreciate the lack of "talk to a lender" wall.
Compare https://whathemortgage.com/ ← similar, for Dutch mortgages. It supports both annuity and linear interest structures. Also open source which might help you!
Compare https://whathemortgage.com/ ← similar, for Dutch mortgages. It supports both annuity and linear interest structures. Also open source which might help you!
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.