$300,000 mortgage at 8%: monthly payment over 30 and 15 years
A $300,000 loan at 8% costs $2,201.29 a month in principal and interest on a 30-year term and $2,866.96 on a 15-year term. Those two numbers, and everything that follows from them, are below — computed with the standard amortization formula, not estimated.
| 30-year fixed | 15-year fixed | |
|---|---|---|
| Monthly principal & interest | $2,201.29 | $2,866.96 |
| Total interest over the term | $492,466 | $216,052 |
| Total paid (principal + interest) | $792,466 | $516,052 |
| Interest as a share of total paid | 62% | 42% |
Principal and interest only. Property taxes, homeowners insurance, mortgage insurance and HOA dues are added to the actual payment. Rates shown are for the arithmetic, not an offer; see 30-year vs 15-year for how to choose.
Where the payments go: the 30-year amortization
Year one: $26,416 paid, $23,909 of it interest, $2,506 principal. That ratio is why equity builds slowly at first and why extra principal payments early are worth the most.
| After | Remaining balance | Paid down |
|---|---|---|
| 5 years | $285,210 | $14,790 |
| 10 years | $263,174 | $36,826 |
| 15 years | $230,345 | $69,655 |
| 20 years | $181,434 | $118,566 |
| 25 years | $108,564 | $191,436 |
Mortgage insurance: the months that matter
The Homeowners Protection Act sets two thresholds on the original value — 80% on request, 78% automatic. Here is when the regular amortization of this loan reaches them, depending on how much was put down:
| Starting LTV | Home value | 80% (request) | 78% (automatic) |
|---|---|---|---|
| 97% | $309,278 | month 152 | month 163 |
| 95% | $315,789 | month 142 | month 154 |
| 90% | $333,333 | month 112 | month 127 |
Extra principal payments or a new appraisal showing appreciation can bring cancellation forward — see PMI removal. FHA mortgage insurance follows different rules.
What a late payment costs
Late fee at day 16: usually 4% to 5% of $2,201.29, so $88.05 to $110.06 (states cap the percentage). Credit reporting at day 30. Foreclosure referral no sooner than 120 days of delinquency under federal rules. See what happens at 30, 60, 90 and 120 days.
The formula
M = P × r(1 + r)n ÷ ((1 + r)n − 1), where P = $300,000, r = 8% ÷ 12 = 0.6667% per month, n = 360 (30 years) or 180 (15 years).
This is the standard fixed-rate amortization — the payment is constant, the interest share falls each month as the balance falls. Balance after k payments: P(1 + r)k − M((1 + r)k − 1) ÷ r.
Frequently asked questions
What is the monthly payment on a $300,000 mortgage at 8%?
$2,201.29 a month for principal and interest on a 30-year fixed loan, or $2,866.96 on a 15-year fixed loan. Property taxes, homeowners insurance, mortgage insurance and any HOA dues are added on top and typically raise the total payment by 25% to 50%.
How much interest will I pay on a $300,000 loan at 8%?
$492,466 over 30 years, or $216,052 over 15 years, if every payment is made as scheduled with no extra principal. In the first year of the 30-year loan, about $23,909 of your $26,416 in payments is interest and $2,506 reduces the balance.
When can I cancel PMI on a $300,000 loan at 8%?
By the regular schedule alone, a loan that started at 95% of the home’s value reaches 80% loan-to-value in month 142 (when you may request cancellation) and 78% in month 154 (automatic cancellation). Extra principal payments or an appraisal showing appreciation can move that earlier.
Same amount, other rates: 5% · 6% · 7%. Same rate, other amounts: $150,000 · $200,000 · $250,000 · $350,000 · $400,000 · $500,000 · $600,000 · $800,000. All tables.