Balance over time
Full amortization schedule
| Period | Payment | Principal | Interest | Extra | Balance |
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Turbo-charge your payoff
How much house can you afford?
Estimates use annual escrow of 1.5% of home price for tax + insurance. Lenders and local requirements vary.
Should you refinance?
Compare two scenarios side-by-side
Scenario A
Scenario B
How to use this mortgage calculator (the right way)
A mortgage is the largest financial commitment most people will ever make, so getting the numbers right matters. This calculator goes beyond the basic "principal and interest" math you'll find on bank websites — it models the full monthly payment (PITI + HOA + PMI), shows you a full amortization schedule, and lets you simulate extra principal payments, bi-weekly schedules, one-time lump sums, refinances, and affordability using the industry-standard 28/36 rule.
Understanding your monthly payment
Your total housing cost (often abbreviated PITI) is a stack of four things: Principal, Interest, Taxes, and Insurance. On top of that, add HOA fees if your property has them and PMI if your down payment is under 20%. Use the pie chart in the Summary tab to see which pieces are eating your budget — for many buyers, taxes and insurance can add 20–30% on top of the "loan payment" they see advertised.
The power of extra payments
Even small extra principal payments compound into enormous savings. Paying just $100 extra per month on a $400,000, 30-year loan at 6.75% can save tens of thousands of dollars in interest and shave multiple years off the loan. Try the Extra Payments tab to run the numbers on your own scenario.
Is refinancing worth it?
A refinance makes sense when the monthly savings pay back your closing costs before you'd move or sell. The break-even month is the honest single metric to watch. Use the Refinance tab — if your break-even is under the number of years you plan to stay, a refi likely pencils out.
How much house can you actually afford?
Lenders use a debt-to-income (DTI) ratio. The conservative rule is 28% of gross income on housing, 36% total. Pushing up to 43% is possible but risky. Our Affordability tab shows all three so you see the trade-off.
Frequently asked questions
How accurate is this calculator?
The math engine uses the standard amortization formula used by every bank and mortgage lender. Monthly amounts match within a few cents; the only variation is that your real lender may round pennies differently and may escrow taxes differently.
What is PMI and when do I pay it?
Private Mortgage Insurance is required by most lenders when your down payment is less than 20% of the home price. Once you reach 20% equity (through payments or appreciation), PMI can be removed. This calculator automatically stops charging PMI the month you cross 20% equity.
Should I take a 15-year or 30-year mortgage?
15-year loans have lower rates and massively less total interest, but higher monthly payments. 30-year loans are more flexible and can be paid off faster with extra payments. Use the Compare tab to see both.
How do bi-weekly payments save money?
Paying half your mortgage every two weeks results in 26 half-payments per year — equivalent to 13 monthly payments, one extra per year. That single extra payment can shave 4–6 years off a 30-year loan.
Is this calculator free?
Yes, 100% free. We're ad-supported. No signup, no email, no paywall.