Finance
Mortgage Calculator
Estimate mortgage payments with tax, insurance, PMI, HOA, and extra principal.
Result
Enter your numbers and press Calculate to see the result.
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How the mortgage payment is calculated
Your total monthly payment is more than the loan itself. This calculator combines the principal-and-interest payment from the standard amortization formula with monthly escrow costs — property tax, home insurance, and PMI — plus any HOA dues and optional extra principal payments.
Formulas
Loan amount = home price − down payment
P&I = P × r(1 + r)ⁿ ÷ ((1 + r)ⁿ − 1)
PMI = loan × PMI% ÷ 12, only while down payment is below 20%
Escrow / monthly extras = annual tax ÷ 12 + annual insurance ÷ 12 + HOA + PMI
Total monthly = P&I + tax/insurance/HOA/PMI + extra principal
Worked example
A $350,000 home with 20% down ($70,000), 6.5% rate, 30 years, $3,600/yr tax and $1,200/yr insurance:
- Loan amount: $280,000
- Principal & interest: ≈ $1,769.79/month
- Escrow: (3,600 + 1,200) ÷ 12 = $400/month
- Total: ≈ $2,169.79 per month.
With a down payment under 20%, lenders typically add PMI — at 0.5% annually, a $280,000 loan would add about $117 per month until you reach 20% equity.
What moves your monthly payment the most
- Interest rate — on a $280,000 loan, each 1% of rate changes principal and interest by about $184/month at current levels, so shopping lenders and locking a good rate matters more than almost anything else.
- Term — a 15-year mortgage has higher monthly payments than a 30-year one but can cut total interest by more than half, because you borrow the money for half as long.
- Down payment — reaching 20% down removes PMI and shrinks the loan, lowering the payment twice over.
- Taxes and insurance — these vary widely by location and can add several hundred dollars a month on top of principal and interest, so always include them when you compare homes.
What the rate is now, and what a rate is worth
The 30-year fixed averaged 6.95% and the 15-year fixed 6.26% in the week of 17 September 2026 (Freddie Mac Primary Mortgage Market Survey, via FRED (MORTGAGE30US, MORTGAGE15US), checked 17 September 2026). Rates move weekly; the point of the table below is not the current number but the shape of the curve.
Principal and interest on a $300,000 loan over 30 years:
| Rate | Monthly P&I | Interest over 30 years | vs today |
|---|---|---|---|
| 3.00% | $1,265 | $155,332 | −$721/mo |
| 4.00% | $1,432 | $215,609 | −$554/mo |
| 5.00% | $1,610 | $279,767 | −$375/mo |
| 6.00% | $1,799 | $347,515 | −$187/mo |
| 7.00% | $1,996 | $418,527 | +$10/mo |
| 8.00% | $2,201 | $492,466 | +$215/mo |
| 9.00% | $2,414 | $568,992 | +$428/mo |
Each percentage point costs roughly $197 a month on this loan around current levels — and about $71,012 over the full term. That is the single largest lever in the whole calculation, which is why an afternoon spent collecting quotes pays better per hour than almost anything else in the process.
For scale, the survey has run since April 1971. Its highest weekly reading was 18.63% in the week of 9 October 1981, and its lowest was 2.65% in the week of 7 January 2021. The same $300,000 loan would have cost $4,676 a month at the peak and $1,209 at the trough — a factor of 3.9 for the identical house.
15 years or 30, at today's rates
Shorter terms carry lower rates, and the two effects compound. On the same $300,000 loan at the rates above:
| Term | Rate | Monthly P&I | Total interest |
|---|---|---|---|
| 30 years | 6.95% | $1,986 | $414,904 |
| 15 years | 6.26% | $2,574 | $163,303 |
The monthly payment rises by about 30%, and total interest falls by $251,601 — roughly 61% less. The trade is liquidity: a 30-year mortgage with voluntary extra payments gets most of the saving while leaving you the option to stop, and a 15-year one does not.
How much house can you afford?
A common guideline is the 28/36 rule: keep total housing costs at or below 28% of your gross monthly income, and all debt payments (housing plus car loans, student loans, and credit cards) at or below 36%. Enter a home price that keeps the total monthly figure inside those limits, then adjust the down payment and term until the payment fits your budget comfortably — lenders approve a maximum, but that is rarely the amount you should borrow.
The mortgage formula
Every fixed-rate mortgage payment comes from the same amortisation formula, where P is the amount borrowed, r is the interest rate per month (the annual rate divided by 12), and n is the number of monthly payments:
M = P × r × (1 + r)ⁿ ÷ ((1 + r)ⁿ − 1)
The calculator adds property tax, insurance, PMI, and HOA on top of this figure, because those are what turn a principal-and-interest number into the amount that actually leaves your account each month.
How much can I borrow?
Lenders answer this two ways, and the lower of the two wins. The first is an income multiple — a rough ceiling of roughly 4 to 4.5 times gross annual income in most markets. The second is an affordability test on your actual monthly commitments, which is where the 28/36 rule above comes in.
A household on £60,000 might see a headline offer near £270,000 from the multiple, then have it cut to £230,000 because of a car loan and childcare. Existing debt reduces borrowing power far more than most people expect: roughly every £100 of monthly commitment removes something like £15,000–£20,000 of borrowing capacity.
Worked example: a 300k house
| Input | Value |
|---|---|
| Home price | 300,000 |
| Down payment (10%) | 30,000 |
| Amount borrowed | 270,000 |
| Rate / term | 6.0% over 30 years |
| Principal and interest | ≈ 1,619 per month |
Add property tax, insurance and PMI and the real monthly figure lands closer to 2,050. Over the full term that loan repays about 583,000 — more than twice what was borrowed. Raising the deposit to 20% removes PMI and drops the payment to roughly 1,439 in principal and interest.
First-time buyers
Three things catch first-time buyers out, and none of them are the monthly payment. Closing costs typically run 2–5% of the price on top of the deposit. Mortgage insurance is charged whenever the deposit is under 20% and is a real recurring cost, not a fee. And the maximum approved is not a budget — lenders test whether you can pay, not whether you will still have a life afterwards.
How this differs outside the US
The arithmetic is identical everywhere; the rules wrapped around it are not. Check current figures with a local lender or regulator, since these limits are revised regularly.
| Market | What is different |
|---|---|
| United Kingdom | Fixed rates usually run 2 or 5 years, then revert to a variable rate — the term is 25–35 years but the rate is not fixed for it. Stamp duty replaces US closing costs. |
| Canada (incl. BC, Ontario) | Rates are fixed for a term, typically 5 years, then renewed against a 25-year amortisation. Lenders test against GDS and TDS ratios of roughly 39% and 44%, and a federal stress test applies above the contract rate. |
| Ireland | Central Bank rules cap most first-time-buyer lending at 4 times income, with a 10% minimum deposit. |
| New Zealand | Loan-to-value restrictions set by the Reserve Bank limit low-deposit lending, and floating rates are far more common than in the US. |
None of these change the payment formula — enter your own rate and term and the result holds in any currency.
For a loan without escrow — a car loan or personal loan — use the loan payment calculator.
Mortgage Calculator — frequently asked questions
How much can I borrow for a mortgage?
Most lenders start at roughly 4 to 4.5 times gross annual income, then cut that figure based on your existing debts and outgoings. The lower of the two tests is what you are offered, and existing monthly commitments reduce it sharply.
What is the monthly payment on a 300k house?
With 10% down, 6% interest and a 30-year term, principal and interest come to about 1,619 a month. Adding property tax, insurance and PMI typically brings the real total closer to 2,050.
What is the mortgage payment formula?
M = P x r x (1 + r)^n / ((1 + r)^n - 1), where P is the amount borrowed, r is the monthly interest rate, and n is the total number of monthly payments.
How much deposit do I need as a first-time buyer?
Under 20% is normal, but anything below that adds mortgage insurance to every payment. Budget separately for closing costs, which usually run another 2 to 5% of the purchase price.
What does the monthly mortgage payment include?
It combines principal and interest from the standard amortization formula with monthly escrow — property tax, home insurance, and PMI divided by 12 — plus any HOA dues and extra principal you choose to pay.
What is PMI and when do I pay it?
Private mortgage insurance is typically required when your down payment is below 20% of the home price. It is charged as an annual percentage of the loan amount and usually drops off once you reach about 20% equity.
How does the down payment change my payment?
A larger down payment shrinks the loan amount, which lowers both the principal-and-interest portion and any PMI. Putting 20% down on a $350,000 home means borrowing $280,000 instead of the full price.
How do extra principal payments help?
Every extra dollar reduces the balance that interest is charged on. Even $100 extra per month on a 30-year loan typically cuts several years off the payoff and saves tens of thousands in interest.