Mortgage Calculator
What will your monthly payment be? Calculate P&I or full PITI, see year-by-year equity built, and compare different rates, terms, and down payments side by side.
Add property tax and insurance to see your total monthly housing cost (PITI).
Try a scenario
How to Use This Calculator
Tab "Monthly Payment"
Enter your home price, down payment (as a percentage or fixed amount), interest rate, and loan term. The result shows your monthly principal-and-interest (P&I) payment, total interest paid, and total cost. Toggle Include property tax & insurance to see your full PITI estimate.
Tab "Amortization Summary"
See your mortgage broken down year by year — how much principal you repay each year, how much interest you pay, your remaining balance, and the equity you have built. The equity bar chart shows your ownership growing over the loan term.
Tab "Compare Scenarios"
Enter a home price and term, then set three different rate/down-payment combinations. The side-by-side table shows monthly payment, total interest, and total cost for each scenario — perfect for deciding between a higher down payment, a shorter term, or waiting for a better rate.
The Formula
PMT = P × r_m × (1 + r_m)^n / ((1 + r_m)^n − 1)
where:
P = loan amount (home price − down payment)
r_m = annual interest rate / 12
n = loan term in months (years × 12)
Total interest paid:
Total interest = (PMT × n) − P
Monthly equity change:
Principal repaid = PMT − (balance × r_m)
New balance = previous balance − principal repaid
All calculations use standard fixed-rate amortization. No country-specific rates, taxes, fees, or insurance rules are applied. Results are estimates only.
Worked Examples
Example 1 — $400,000 home, 20% down, 6% for 30 years
A buyer puts 20% down ($80,000) on a $400,000 home, taking a $320,000 loan at 6% fixed for 30 years.
At 6% for 30 years, you pay more than the loan amount again in interest alone. Total cost is 1.72× the original loan.
Example 2 — Same home at 15 years: save $205,000 in interest
Same $320,000 loan at 6% but over 15 years instead of 30.
The monthly payment is $783 higher, but you save over $204,000 in interest and own your home outright 15 years earlier. The break-even: paying $783/mo extra for 15 years ($140,940 total extra) to save $204,261 — a net gain of over $63,000, plus the peace of mind of being mortgage-free earlier.
Example 3 — 5% down vs 20% down: monthly cost and 5-year equity
Comparing two buyers on the same $400,000 home at 6.5% for 30 years.
| Scenario | Down payment | Loan amount | Monthly P&I | Equity after 5 yrs | Total interest |
|---|---|---|---|---|---|
| 5% down | $20,000 | $380,000 | $2,402 | $47,800 | $485,000 |
| 20% down ★ | $80,000 | $320,000 | $2,023 | $112,600 | $408,000 |
The 20%-down buyer pays $379/mo less, has $64,800 more equity after 5 years, and saves $77,000 in total interest — in addition to avoiding PMI (typically $100-$200/mo on the 5%-down scenario). The 5%-down buyer gets into the home sooner but at significantly higher lifetime cost.
Understanding Your Mortgage
Principal vs Interest: the early payment trap
In a 30-year mortgage at 6%, your first payment on a $320,000 loan is approximately $1,919. Of that, $1,600 goes to interest and only $319 reduces your balance. By month 360, almost all of each payment is principal. This is why the first few years feel like you are "treading water" — you are mostly paying the lender for the use of money, not building equity. Making even one extra payment per year in the early years can cut years off your loan and save tens of thousands in interest.
What PITI includes
Principal + Interest is what this calculator shows by default. Your actual monthly housing cost also includes:
- Property tax — varies widely by location, typically 0.5% to 2.5% of home value per year. Enable the PITI toggle to estimate this.
- Homeowner's insurance — typically $800 to $2,000/year depending on home value and location.
- PMI — private mortgage insurance applies when your down payment is under 20%. Typically 0.5% to 1.5% of the loan amount per year, added to your monthly payment until you reach 20% equity.
- HOA fees — if applicable. Not included in this calculator.
Fixed rate vs adjustable rate
This calculator uses a fixed-rate mortgage — your interest rate and monthly payment stay constant for the entire term. An adjustable-rate mortgage (ARM) starts with a lower fixed rate for an introductory period (e.g. 5 or 7 years), then adjusts periodically based on a market index. ARMs can be cheaper short-term but introduce uncertainty. If you plan to sell or refinance within 5-7 years, an ARM may make sense; for long-term ownership, a fixed rate provides predictability.
How equity builds
Your equity is the portion of the home you own outright: home value minus remaining loan balance. It grows in two ways: (1) each mortgage payment reduces your balance, and (2) if home prices rise, the asset value grows. The Amortization Summary tab shows year-by-year equity growth assuming a constant home value — real equity may be higher if prices appreciate. At the halfway point of a 30-year mortgage (year 15), you have paid about 58% of total interest but only reduced your balance by about 33%.
The impact of the interest rate
A 1% difference in rate has a dramatic effect over a 30-year loan. On $320,000:
| Rate | Monthly P&I | Total interest |
|---|---|---|
| 5.0% | $1,717 | $298,000 |
| 6.0% | $1,919 | $371,000 |
| 7.0% | $2,129 | $446,000 |
| 8.0% | $2,348 | $525,000 |
Going from 5% to 8% costs an extra $631/month and $227,000 in total interest. This is why refinancing when rates fall — even by 1% — can be worth the closing costs.
Frequently Asked Questions
Country-Specific Mortgage Calculators
For local mortgage calculators that include stamp duty, government schemes, and country-specific rules: