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Mortgage Calculator — See Your Real Monthly Payment

Plug in your numbers and see exactly what you'll pay each month. This calculator shows principal + interest breakdown, total cost over the life of the loan, and how much of your early payments go straight to interest (spoiler: most of it).

Calculate monthly payments, total interest, and total payment

Calculation Result
Calculate monthly payments, total interest, and total payment
Calculate monthly payments, total interest, and total payment

How Mortgage Math Works

Your monthly payment is calculated using the standard amortization formula: M = P × [r(1+r)^n] / [(1+r)^n - 1], where P is the loan principal (home price minus down payment), r is the monthly interest rate (annual rate ÷ 12), and n is the total number of payments (years × 12).

Here's what surprises most first-time buyers: on a 30-year loan at 6.5%, your first payment is roughly 65% interest and 35% principal. You don't hit 50/50 until about year 17. That's why the first few years of extra principal payments have an outsized impact — every extra dollar skips the interest queue.

Important distinction: the rate you enter here should be the nominal interest rate (what's used to calculate payments), NOT the APR. The APR includes fees and closing costs spread over the loan term, so it's always slightly higher. Your lender quotes both — use the lower number (nominal rate) for payment calculation.

How to Use

  1. Enter the home price (or total loan amount if you already know it).
  2. Enter your down payment as a percentage — 20% avoids PMI, but 5-10% is common for first-time buyers.
  3. Enter the loan term — 30 years is standard, 15 years saves massive interest but costs more monthly.
  4. Enter the annual interest rate (nominal rate, not APR) and hit Calculate.

When This Calculator Helps

Figuring out how much house you can afford

Work backwards: if you can comfortably pay $2,500/month, what loan amount does that support at current rates? Adjust the home price until the monthly payment fits your budget. General rule: keep housing under 28% of gross income.

Comparing 15-year vs 30-year loans

On a $400,000 loan at 6.5%: 30-year = $2,528/month, total interest = $510,177. 15-year = $3,484/month, total interest = $227,181. You pay $956 more per month but save $283,000 in interest. Run both scenarios here to see your actual numbers.

Deciding how much to put down

Putting 20% down on a $500K house ($100K) vs 5% ($25K) changes your monthly payment by about $475 and eliminates PMI (~$200/month). But that extra $75K tied up in the house could earn returns elsewhere. This calculator helps you see the monthly impact.

Evaluating a refinance

If rates drop 1% below your current rate, is it worth refinancing? Calculate your new payment, compare to the old one, multiply the monthly savings by the remaining months, and subtract closing costs (~$3-5K). If you break even within 2-3 years, it's usually worth it.

Things Most Calculators Don't Tell You

1.

This shows principal + interest only

Your actual monthly payment includes property taxes (~1-2% of home value annually), homeowner's insurance (~$100-300/month), and PMI if you put less than 20% down (~0.5-1% of loan annually). Add 30-40% to the number you see here for a realistic budget.

2.

Use the nominal rate, not APR

APR includes origination fees and closing costs amortized over the loan term. It's useful for comparing lenders, but it's NOT the rate used to calculate your monthly payment. Use the base interest rate your lender quotes.

3.

Extra payments early on save the most

Adding $200/month extra principal to a $400K/30yr/6.5% loan saves $98,000 in interest and pays off the loan 5 years early. The earlier you start, the more you save — because you're eliminating future interest that would have compounded.

4.

Don't forget opportunity cost

A bigger down payment means lower monthly payments, but that cash could earn 7-10% annually in index funds. If your mortgage rate is 6.5% and the market averages 9%, the math might favor a smaller down payment and investing the difference. Run both scenarios.

Example Calculations

$400,000 home, 20% down, 30 years at 6.5%

A typical scenario for a mid-range home purchase in 2026.

Input

Home price: $400,000 | Down payment: 20% ($80,000) | Loan: $320,000 | Term: 30 years | Rate: 6.5%

Output

Monthly payment: $2,023 | Total interest: $408,141 | Total paid: $728,141 | First payment: $1,733 interest + $290 principal

Same loan but 15-year term

See how much interest you save with a shorter term.

Input

Home price: $400,000 | Down payment: 20% ($80,000) | Loan: $320,000 | Term: 15 years | Rate: 6.0%

Output

Monthly payment: $2,700 | Total interest: $165,952 | Total paid: $485,952 | Savings vs 30yr: $242,189 in interest

Features

  • Instant monthly payment calculation with principal/interest split
  • Total interest and total cost over the full loan term
  • Supports any loan amount, term, and rate
  • Shows how much of each payment goes to interest vs principal
  • All math runs in your browser — no data stored
  • Free, no signup, no ads

Frequently Asked Questions

How much house can I afford on an $80K salary?

The 28% rule says your housing payment should be under 28% of gross monthly income. On $80K that's ~$1,867/month for principal + interest. At 6.5% for 30 years with 20% down, that supports roughly a $350,000 home. But remember to budget for taxes and insurance on top.

What's the difference between 15-year and 30-year mortgages?

On a $320K loan at 6.5%: 30-year costs $2,023/month but $408K total interest. 15-year costs $2,787/month but only $181K total interest. You pay $764 more per month but save $227,000 over the life of the loan. 15-year rates are also typically 0.5-0.75% lower.

Should I put 20% down or less?

Putting less than 20% down means paying PMI (private mortgage insurance) — typically 0.5-1% of the loan amount per year. On a $320K loan that's $133-267/month extra. If you can hit 20%, you eliminate that cost immediately. But if it takes you 5 more years to save 20%, buying sooner at 10% down might make sense depending on home price appreciation in your market.

Does this calculator include property taxes?

No — this shows principal and interest only. Property taxes vary wildly by location (0.3% in Hawaii to 2.5% in New Jersey). Add your local tax rate × home value ÷ 12 to get your real monthly cost. Most lenders collect this in escrow as part of your payment.

How do extra payments affect my mortgage?

Extra principal payments reduce your loan balance faster, which means less interest accrues each month. On a $320K/30yr/6.5% loan, paying just $100 extra per month saves $52,000 in interest and pays off the loan 4 years early. Use our Mortgage Payoff Calculator to model specific scenarios.

Tips & Related Workflows