The short answer
- On $300,000 at 7.25% over 30 years, the payment is $2,046.53 a month and total interest is $436,750, more than the amount borrowed.
- In the first year, $21,655 of your $24,558 in payments goes to interest. Only $2,904 reduces the balance.
- The payment does not split mostly toward principal until payment 246, in May 2047: more than 20 years in.
- An extra $200 a month pays the loan off in August 2049 instead of November 2056 and saves $123,590 of interest.
What amortization means
To amortize a loan is to pay it off in equal installments that cover both interest and principal, so that the last payment leaves a balance of zero. Most US mortgages, car loans, personal loans and student loans work this way. The payment stays the same each month, but its make-up changes: interest is charged on the balance, so as the balance falls, the interest part shrinks and the principal part grows.
The schedule is fixed the day the loan starts. Given the amount, the rate and the term, you can say exactly what you will owe after 37 payments or after 212. That is what this calculator shows, month by month, with dates.
How the payment is worked out
Lenders use one formula. With the loan amount P, the monthly rate r (the yearly rate ÷ 12) and the number of payments n, the payment is P × r ÷ (1 − (1 + r)−n). It is the only level payment that clears the loan in exactly n months.
Each month the lender then does two simple steps. Interest = balance × r. Principal = payment − interest. The new balance is the old balance minus that principal. Repeat 360 times and you have the whole schedule. Interest is charged on what you still owe, not on the original amount, which is why the split shifts over time.
Inside your first payment
- Monthly rate7.25% ÷ 120.6042%
- Monthly paymentFrom the formula$2,046.53
- Interest in month 1$300,000 × 0.6042%$1,812.50
- Principal in month 1$2,046.53 − $1,812.50$234.03
Almost nine dollars in ten of that first payment is interest. The next month, interest is charged on $299,765.97, which is slightly less, so a few cents more go to principal. That small shift repeats every month for 30 years.
A 30-year schedule, year by year
| Year | Principal paid | Interest paid | Balance at year end |
|---|---|---|---|
| 2027 | $2,921 | $21,637 | $296,845 |
| 2031 | $3,900 | $20,658 | $282,800 |
| 2036 | $5,599 | $18,960 | $258,449 |
| 2046 | $11,534 | $13,024 | $173,326 |
| 2056 | $21,717 | $795 | $0 |
Every full year costs the same $24,558 in payments. In 2027 nearly all of it is interest; by 2056 nearly all of it is principal. The calculator shows every calendar year, and you can open any year to see its twelve monthly rows.
The tipping point
The tipping point is the first payment where more goes to principal than to interest. On this loan it is payment 246, in May 2047, more than two-thirds of the way through. The higher the rate and the longer the term, the later it comes. At the same 7.25%, a 20-year loan tips at payment 126, a 15-year loan at payment 66 and a 10-year loan at payment 6.
The calculator shows your tipping point in the first-year card. It is a good way to see how much of a long loan is spent just carrying the debt.
How fast you build equity
| After | Balance | Paid off | Interest paid so far |
|---|---|---|---|
| 1 year | $297,096 | $2,904 | $21,655 |
| 5 years | $283,136 | $16,864 | $105,928 |
| 10 years | $258,931 | $41,069 | $204,515 |
| 15 years | $224,188 | $75,812 | $292,563 |
| 20 years | $174,319 | $125,681 | $365,486 |
| 25 years | $102,741 | $197,259 | $416,699 |
You owe half the original amount only after payment 263, in October 2048, nearly 22 years in. Over the first five years you pay down less than $17,000. This matters if you plan to sell or refinance: in the early years most of your equity comes from your down payment and any rise in the home’s value, not from your payments.
15, 20 or 30 years
- Payment
- $2,046.53
- Total interest
- $436,750
- Payment
- $2,371.13
- Total interest
- $269,071
- Payment
- $2,629.84
- Total interest
- $173,372
A shorter term raises the payment but cuts interest sharply, both because you borrow for less time and because 15-year loans usually carry lower rates. Freddie Mac’s survey put the 15-year average about 0.7 points below the 30-year on October 1, 2026. Even at the same 7.25%, the 15-year payment of $2,738.59 brings total interest down to $192,946.
What the rate does to the schedule
Total interest on $300,000 over 30 years climbs steeply with the rate. At 3% it is about half the loan; at 7.25% it is nearly one and a half times the loan. The payment moves less: from $1,264.81 at 3% to $2,046.53 at 7.25%. That is why a small rate cut can save tens of thousands over a full term, and why the mortgage points calculator is worth a look before you lock a rate.
Extra monthly payments
| Extra each month | Last payment | Interest saved |
|---|---|---|
| None | November 2056 | – |
| $100 | August 2052 | $73,785 |
| $200 | August 2049 | $123,590 |
| $500 | February 2044 | $210,853 |
Extra principal skips you ahead on the schedule. Each extra dollar removes a dollar of balance that would otherwise have charged 7.25% a year for the rest of the loan. With $100 a month, you put in $30,800 of extra principal and save $73,785 of interest.
Yearly and one-time extras
Not everyone can spare money every month. A yearly extra, such as part of a tax refund, works too. Paying $2,000 extra every April on the same loan ends it in June 2050 and saves $109,920 of interest, for $48,000 of extra principal in all.
A one-time lump sum early in the loan is powerful. $10,000 paid with the seventh payment, in June 2027, moves the payoff from November 2056 to November 2053 and saves $65,133 of interest. The calculator lets you combine all three kinds of extra payment and see the effect on each month of the schedule.
Why early extras count most
The same $10,000 paid 20 years in, with the December 2046 payment, saves only $9,942 of interest and ends the loan in February 2056, nine months early. Paid in June 2027, it saved $65,133. Early money has decades of interest to avoid; late money has only a few years.
Check for a prepayment penalty
Most mortgages made since 2014 have no prepayment penalty, and where one is allowed it can only apply in the first three years. Your Loan Estimate and Closing Disclosure say whether yours has one.
Extra payments and recasting
On a US mortgage, an extra payment does not lower your required payment. It shortens the loan instead, and the schedule above shows exactly that: the payment stays at $2,046.53 and the last payment moves earlier. Some servicers will “recast” the loan after a large lump sum, for a fee of a few hundred dollars: they recompute the payment over the remaining term on the new, lower balance. Recasting lowers your payment but saves less interest than keeping the payment and finishing early.
Payment dates and the first payment
Mortgage interest is paid in arrears: the payment due on January 1 covers December’s interest. At closing you prepay interest from the closing date to the end of that month, and the first regular payment is usually due on the first day of the second month after closing. Close on October 20, 2026, for example, and the first payment is typically due December 1, 2026.
Enter that first payment date in the calculator and every row of the schedule shows its month and year. The last payment date is the one to circle: it is when the home is yours outright.
What the schedule leaves out
An amortization schedule covers principal and interest only. Most mortgage payments also include property tax and homeowners insurance, collected into an escrow account, and sometimes PMI. Those parts can change each year, so your actual bill can rise even on a fixed-rate loan. To see the full monthly cost with tax, insurance, PMI and HOA dues, use the mortgage calculator.
Car, personal and student loans
The same schedule applies to any fixed-rate installment loan. A $30,000 car loan at 7.5% over 60 months costs $601.14 a month and $6,068 of interest. Set the term in years (5 for 60 months) and the calculator does the rest. For loans with fees, compare the APR; the loan calculator covers personal loans with an origination fee, and the auto loan calculator adds sales tax and a trade-in.
Adjustable-rate and interest-only loans
On an adjustable-rate mortgage (ARM), the schedule holds only until the first rate change, often after five, seven or ten years. At each reset the lender recomputes the payment over the remaining term at the new rate. You can model that here by running the remaining balance at the new rate for the years left.
Interest-only loans and home equity lines of credit do not amortize during their draw or interest-only period, so the balance does not fall at all unless you pay extra. The HELOC calculator shows how the payment jumps when such a loan starts to amortize.
Checking your own statement
Your monthly mortgage statement shows the principal and interest split of your last payment and your current balance. Compare them with the calculator’s row for the same month. Small differences of a few cents come from rounding, which servicers do each month. A larger gap usually means the start date, rate or amount entered does not match the loan, or that an extra payment was applied to escrow rather than principal. When you send extra money, write “apply to principal” or choose that option online.
The schedule and your taxes
If you itemize deductions, mortgage interest on up to $750,000 of debt used to buy, build or improve your home is generally deductible (IRS Publication 936). The yearly interest column in the schedule is close to what your servicer reports on Form 1098 each January. Because interest falls each year, the deduction shrinks over time. Most households take the standard deduction ($32,200 for married couples filing jointly in 2026), so for them the interest gives no tax benefit at all.
Using the calculator well
- Enter the loan amount, the note rate (not the APR) and the term in years.
- Set the first payment date so the schedule shows real months.
- Under More options, add any monthly, yearly or one-time extra payment.
- Read the first-year card, the balance chart and the yearly table, and open a year to see each month.
- Share the page link: it keeps your inputs.
To plan a payoff by a target date, or to compare paying extra with investing, use the mortgage payoff calculator.
Key numbers
| Item | Figure |
|---|---|
| Monthly rate | Yearly rate ÷ 12 |
| Payment formula | P × r ÷ (1 − (1 + r)^−n) |
| $300,000 at 7.25%, 30 years | $2,046.53 a month, $436,750 interest |
| Same loan, 15 years at 6.6% | $2,629.84 a month, $173,372 interest |
| Average 30-year rate (October 1, 2026) | about 7.3% |
| Average 15-year rate (October 1, 2026) | about 6.6% |
| Mortgage interest deduction cap | $750,000 of home debt |