AmortMapWhat a given loan amount actually costs per month, and over its life.

Monthly payment on a $150k mortgage at 6.5%

$150k at 6.5%
$948per month
principal and interest only over 30 years — the real bill is $1,059–$1,384
$150k at 6.5% — monthly$94830 yr P&I$1,384with escrow$1,30715 yr P&Isolid = principal and interest · shaded = tax, insurance and PMI
Principal & interest, 30 yr$948
Realistic total paymentadds property tax, insurance and PMI — the range is mostly state tax$1,059–$1,384
Total interest over 30 yrmore than the amount borrowed$191,317
20-year payment$1,118
15-year payment$359 more a month, $106,118 less interest$1,307
First payment: interest$813
First payment: principalonly 14% of the payment touches the debt$136
Per $1,000 borrowedscales linearly at 6.5% over 30 years$6.32

Notes

  • The quoted payment is not the bill. $948 is principal and interest. Property tax, homeowner's insurance and — under 20% down — private mortgage insurance are collected alongside it, and on this loan they add roughly $111 to $436 a month.
  • Property tax is the biggest variable and it is geographic. Effective rates run from about 0.3% of value in the lowest states to over 2% in the highest — a factor of six on the same house. That single line moves the monthly bill here by roughly $250, which is more than a full percentage point of interest rate.
  • Where the money goes early on. The first payment is $813 interest and $136 principal — 14% of it reduces the debt. The crossover, where principal first exceeds interest within a single payment, arrives around year 19 at this rate. That asymmetry is why an extra payment in year two is worth many times the same payment in year twenty.
  • Fifteen years costs $359 more a month and saves $106,118 in interest. Whether that is a good trade depends on what the extra $359 would otherwise do — which is a different question from which loan is cheaper.
  • Payment scales linearly with the amount at a fixed rate: $6.32 per $1,000 borrowed at 6.5% over 30 years. That shortcut works for any figure, not just the round ones.

The short answer

A $150k mortgage at 6.5% over 30 years costs $948 a month in principal and interest.

The actual bill is closer to $1,059–$1,384, and the gap is made of three things a rate table cannot know.

What the calculator leaves out

Line On this loan
Principal & interest $948
Property tax varies six-fold by state
Homeowner's insurance roughly 0.5% of value a year
PMI, if under 20% down roughly 0.6% of the loan a year

Property tax is the biggest variable and it is geographic. Effective rates run from about 0.3% of value in the lowest states to over 2% in the highest. On this loan that single line moves the monthly bill by more than a full percentage point of interest rate would.

PMI disappears at around 20% equity. Tax and insurance do not.

Where the money goes early on

The first payment is $813 interest and $136 principal — only 14% of it reduces the debt.

Interest is charged on the outstanding balance, which is largest at the beginning. That asymmetry is why an extra payment made in year two removes far more total interest than the same payment in year twenty, and it is the whole argument for paying early rather than paying more.

Term changes the shape completely

Term Monthly Total interest
30 years $948 $191,317
20 years $1,118
15 years $1,307 $85,199

Fifteen years costs $359 more a month and saves $106,118 in interest.

Whether that is a good trade depends on what the extra $359 would otherwise do. It is a question about your other options, not about which loan is cheaper — the shorter loan is always cheaper.

The shortcut for any other amount

At 6.5% over 30 years, each $1,000 borrowed costs $6.32 a month.

Payment scales linearly with the amount at a fixed rate, so that figure answers any loan size without another calculation.

What actually moves the payment

Rate and term, in that order. A quarter-point of rate is worth more on a large loan than most people expect, and it is the reason shopping more than one lender is the highest-return hour available in the whole process.

Points — paying 1% of the loan up front to lower the rate by roughly a quarter point — pay for themselves in about five years. Whether that is worth it depends on how long the loan will actually be held, and the median is closer to a decade than to thirty years.

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