See exactly how every payment splits between principal and interest — month by month, year by year. Works for mortgages, auto loans, personal loans, and student loans.
Quick answer: A $300,000 mortgage at 7% for 30 years = $1,996/mo · Total interest: $418,527 · You pay more in interest than principal for the first 21 years.
Loan Details
$
%
Extra Payments (optional)
$
$
Monthly Payment
$1,996
Total Cost
$718,527
Total Interest
$418,527
Payoff Date
March 2056
Payment Breakdown
Principal (Loan Amount)
$300,000
Total Interest Paid
$418,527
Loan Amount$300,000
APR7.00%
Term360 months
Monthly Payment$1,996
Total Payments$718,527
Total Interest$418,527
Interest / Principal CrossoverMonth 253 (Year 22)
Payoff DateMarch 2056
Extra payments save $0 in interest and cut 0 months off your loan term. New payoff: —.
Side-by-side comparison
Standard
$1,996
monthly payment
Total interest$418,527
PayoffMar 2056
With Extra Payments
$1,996
monthly payment
Total interest$418,527
PayoffMar 2056
Balance & Payment Breakdown Over Time
Remaining BalancePrincipal PaidInterest Paid
View amortization chart data as table
The full amortization schedule is available in the Year-by-Year and Month-by-Month tabs below.
Year
Principal Paid
Interest Paid
Total Paid
Remaining Balance
#
Date
Payment
Principal
Interest
Balance
How Amortization Works
Amortization is the process of paying off a loan through equal periodic payments. Each payment covers that month's interest first, and whatever's left reduces your principal balance. This is why in the early years of a 30-year mortgage, most of your payment goes to interest — and the last few years are almost entirely principal.
The amortization formula
Monthly payment = P × r / (1 − (1 + r)−n) where P = loan amount, r = monthly interest rate (APR ÷ 12), and n = total number of monthly payments. Each month's interest = remaining balance × r. Each month's principal = monthly payment − interest.
Why the first payment is mostly interest
On a $300,000 mortgage at 7% APR, month 1 interest = $300,000 × 0.5833% = $1,750. Your $1,996 payment covers that, leaving only $246 to reduce your balance. By month 360, your balance is ~$1,990 and your interest is only ~$12 — almost the entire payment kills the remaining debt.
Extra payments — the math
Extra payments reduce the principal directly, which lowers every future month's interest. On a $300,000 / 7% / 30-year mortgage, adding just $200/month extra saves ~$86,000 in interest and cuts the term by ~6 years. A $10,000 lump sum in year 1 saves ~$31,000 in total interest. Use the calculator above to model your exact scenario.
Typical loan terms and rates (2026)
Loan Type
Typical Term
2026 Rate Range
$300K / Best Rate / Monthly
30-Year Mortgage
30 years
6.5% – 7.5%
$1,896 – $2,098
15-Year Mortgage
15 years
6.0% – 7.0%
$2,532 – $2,694
Auto Loan (new)
5–7 years
5.5% – 8.5%
$3,212/mo (5yr, $30K)
Personal Loan
2–7 years
7% – 25%
varies by amount
Student Loan (federal)
10–25 years
5.5% – 8.0%
fixed by program
Amortization vs simple interest
Standard loans (mortgages, auto, personal) use amortizing interest — the balance and interest recalculate monthly. Some older car loans use Rule of 78s (pre-computed interest front-loaded), which penalizes early payoff. Always confirm your loan uses simple monthly amortization before making extra payments, especially on older auto loans.
Calculations use standard amortization formula per IRS Publication 936 and CFPB mortgage guidelines. Rates are national averages for illustrative purposes. Freddie Mac PMMS (Primary Mortgage Market Survey) is the authoritative source for current mortgage rates. · Methodology
Frequently Asked Questions
What is the difference between an amortization schedule and a payment schedule?▾
A payment schedule shows only how much you owe each month and when. An amortization schedule goes deeper — it shows exactly how each payment is split between principal and interest, and what your remaining balance is after each payment. Amortization schedules are critical for understanding the true cost of a loan and for planning extra payments.
When does a 30-year mortgage reach 50% principal paid?▾
For a standard 30-year mortgage at 7%, you cross the 50% principal paid mark around year 21–22. This is the "crossover" point shown in the calculator. Before that point, every payment you make goes more toward interest than principal. After year 22, your monthly payment starts killing more debt than it costs in interest. This is why paying even a little extra in the first 5–10 years has an outsized impact.
Does making extra payments reduce the monthly amount or shorten the term?▾
By default, most lenders apply extra payments to reduce the term — your required monthly payment stays the same, but your loan ends earlier. Some lenders let you choose to "recast" the loan, which recalculates a lower required payment on the reduced balance. Recasting is better for cash flow; keeping the payment the same is better for total interest savings. Ask your lender which option they support.
What is negative amortization?▾
Negative amortization happens when your monthly payment is less than the interest accrued for that month. The unpaid interest gets added to your principal balance — meaning your debt grows even as you're making payments. This happened on some adjustable-rate mortgages (ARMs) during 2004–2008. Modern QM (Qualified Mortgage) rules prohibit negative amortization on most consumer loans, but it can still occur on some student loans during deferment or income-driven repayment periods.
Can I deduct mortgage interest on my taxes?▾
Yes, for most homeowners. The mortgage interest deduction allows you to deduct interest paid on up to $750,000 of mortgage debt (for loans originated after December 15, 2017). This deduction is only available if you itemize deductions — with the 2026 standard deduction at $15,000 (single) and $30,000 (married), most taxpayers don't itemize. The amortization schedule shows exactly how much interest you pay each year, which is the figure you would report on Schedule A.
How does a 15-year mortgage compare to a 30-year mortgage?▾
On a $300,000 loan: a 30-year at 7% costs $1,996/month and $418,527 in total interest. A 15-year at 6.5% costs $2,614/month and $170,520 in total interest. The 15-year payment is $618/month higher, but you save nearly $248,000 in interest and own your home outright 15 years earlier. If you can afford the payment, the 15-year almost always wins on total cost. Use the calculator to run both scenarios side by side.