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Loan & Mortgage Calculator

Monthly payment, total interest, and full amortization — instant.

The monthly payment number is seductive — it turns a $300,000 commitment into something that feels like a Netflix subscription. The amortization table is the antidote: it shows exactly how much of that payment is interest (most of it, at first) and how the balance actually falls. This calculator gives you both.

Monthly payment
$1,580.17
Total paid
$568,861.22
Total interest
$318,861.22
Payments
360
YearPrincipalInterestBalance
1$2,794.31$16,167.73$247,205.69
2$2,981.45$15,980.59$244,224.23
3$3,181.13$15,780.91$241,043.10
4$3,394.17$15,567.87$237,648.93
5$3,621.49$15,340.55$234,027.44
6$3,864.03$15,098.02$230,163.42
7$4,122.81$14,839.23$226,040.61
8$4,398.92$14,563.12$221,641.69
9$4,693.52$14,268.52$216,948.17
10$5,007.86$13,954.18$211,940.32
11$5,343.24$13,618.80$206,597.07
12$5,701.09$13,260.95$200,895.99
13$6,082.90$12,879.14$194,813.09
14$6,490.28$12,471.76$188,322.80
15$6,924.95$12,037.09$181,397.85
16$7,388.73$11,573.31$174,009.13
17$7,883.56$11,078.48$166,125.56
18$8,411.54$10,550.50$157,714.02
19$8,974.88$9,987.16$148,739.15
20$9,575.94$9,386.10$139,163.21
21$10,217.26$8,744.78$128,945.95
22$10,901.53$8,060.51$118,044.42
23$11,631.62$7,330.42$106,412.80
24$12,410.61$6,551.43$94,002.18
25$13,241.78$5,720.26$80,760.41
26$14,128.60$4,833.44$66,631.80
27$15,074.82$3,887.22$51,556.98
28$16,084.41$2,877.63$35,472.57
29$17,161.61$1,800.43$18,310.96
30$18,310.96$651.08$0.00

How amortization works — and why early payments hurt

Every fixed-rate loan uses the same mechanism: each payment is split between interest (charged on the remaining balance) and principal (reduction of what you owe). In month one, almost all of your payment is interest. In month 360 of a 30-year mortgage, it's almost all principal.

That front-loading is the reason extra payments are so powerful early on. Making one extra payment in year 1 reduces the principal by the full extra amount — which reduces the interest charged on every remaining payment. Making that same extra payment in year 25 saves almost nothing, because the balance is already small.

The true cost of a lower rate

Borrowers obsess over monthly payment differences. A better frame is total interest cost. At 6.5% APR on a $250,000 / 30-year mortgage, you pay $318,000 total — $68,000 in interest. At 7.5%, that climbs to $350,000 — $100,000 in interest. The $95/month difference compounds into $32,000 over three decades.

This is why shopping for rate is worth more than negotiating price on the appliances. A 0.5-point rate reduction on a $400,000 mortgage saves more than the cost of the inspection, lawyer, and moving truck combined.

15-year vs 30-year mortgages

The two most common mortgage terms make a stark trade-off.

  • 30-year: lower monthly payment, more flexibility, but you pay roughly 2× as much total interest as you would on a 15-year at the same rate.
  • 15-year: payment is ~40% higher, but you build equity fast and pay roughly half the interest. Rate is usually 0.5–0.75% lower than the 30-year as well.
  • Hybrid approach: take the 30-year for payment security, but pay as if it's a 25-year. You get flexibility without paying the full 30-year interest cost.
  • Break-even on the 15-year depends on your alternative: if you'd invest the monthly-payment difference at 7%+ returns, the 30-year can win mathematically. Most people don't — the forced savings of a 15-year wins behaviorally.

How much loan can you actually afford?

Lenders use debt-to-income (DTI) ratio: total monthly debt payments divided by gross monthly income. Most conventional loans cap at 43–45% back-end DTI (all debts). A safer personal rule: keep housing costs under 28% of gross income (the 'front-end' ratio).

On a $100,000 gross income ($8,333/month), 28% = $2,333 in housing costs. At 6.5% APR, that buys roughly a $370,000 loan. Add down payment and you have your target price range.

How to use the loan calculator

Three inputs, instant results. Here's how to get the most out of it.

  1. 1
    Enter the loan amount
    For a mortgage, this is the purchase price minus your down payment. For a car or personal loan, it's the amount you're borrowing. Don't include taxes and insurance here.
  2. 2
    Set the APR
    Use the Annual Percentage Rate your lender quoted, not just the interest rate. APR includes fees and gives a more accurate picture of true cost. Check your loan offer letter or use current average rates from a rate comparison site.
  3. 3
    Set the term
    Standard mortgages are 15 or 30 years. Car loans are typically 3–7 years. Personal loans 2–7 years. A shorter term = higher monthly payment but dramatically lower total interest.
  4. 4
    Read the amortization table
    Scroll through the year-by-year breakdown. Note when the principal share of each payment finally exceeds the interest share — that's your equity inflection point.
  5. 5
    Test the 'extra payment' scenario
    Reduce the term by 2–3 years in the calculator and see what the new monthly payment would be. If the difference is manageable, you've just found a discipline-free way to pay off your loan years early.

FAQ

How is a loan monthly payment calculated?
Using the amortization formula: M = P × r × (1+r)^n / ((1+r)^n − 1), where P is principal, r is the monthly rate (APR/12), and n is the number of payments.
What's the difference between APR and interest rate?
The nominal interest rate is the rate charged on the loan. APR includes that rate plus mandatory fees, giving a closer picture of true yearly cost.
Does this include taxes and insurance?
No — it shows principal + interest only (P&I). For full PITI, add your local property tax and insurance separately.
What happens if I make one extra payment per year?
On a standard 30-year mortgage you'll typically cut 4–5 years off the term and save tens of thousands in interest. The earlier in the loan you start, the bigger the effect — because early payments are mostly interest.
How much does a 1% rate difference cost over 30 years?
On a $250,000 mortgage, moving from 6% to 7% APR adds roughly $170/month and about $62,000 in total interest over the life of the loan. Use the calculator to run your own numbers — the exact figure depends heavily on loan size.
What is an amortization schedule?
A month-by-month (or year-by-year) breakdown of each payment: how much goes to interest, how much reduces the principal, and what balance remains. Early payments are mostly interest — the principal share grows over time.

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