How to Read a Mortgage Amortization Schedule

An amortization schedule is your entire mortgage written out in advance — every payment from the first to the last, calculated at closing. A 30-year loan has 360 rows.

Here are the first twelve payments on a $400,000 loan at 6.25% over 30 years:

Payment number

Which payment this is, 1 to 360. Some schedules show a date instead, some show both. Useful as a progress marker: payment 120 means you are exactly a third of the way through a 30-year loan by count — though, as the balance column shows, nowhere near a third of the way by debt.

Payment amount

$2,462.87, on every single row. This is the column people misread most often. It does not change, ever, on a fixed-rate loan. What changes is how it is divided.

Note this is principal and interest only. Your actual monthly bill probably also includes property taxes, homeowners insurance and possibly mortgage insurance. Those are escrow items — they pay third parties and never appear in an amortization calculation.

Interest

What the lender charges you this month for the money you still owe. It is always calculated the same way:

This column only ever goes down, because your balance only ever goes down. This is money that leaves and does not come back — it buys you nothing you keep.

Principal

The part that actually reduces your debt — the only column that builds ownership. It is simply what is left after the interest is taken:

This column only ever goes up. Interest and principal always sum to the payment amount, so as one shrinks the other grows by the identical amount.

Remaining balance

What you owe after this payment. Last row's balance minus this row's principal. It hits exactly $0.00 on the final row — that is what "amortizing" means.

Interest to date (cumulative)

Not every schedule includes it; the ones that do are more honest. It is the running total of interest paid so far. After twelve payments here it reads $24,867.25 — against $4,687.19 of principal. Worth knowing before you see it.

You do not need to read 360 rows. Three of them tell you almost everything.

Row 1 — what your money is actually buying today

Look at the interest-to-principal ratio on your very first row. Here it is $2,083.33 to $379.54 — 84.6% of the payment is interest. This single row explains why the balance seems not to move in the early years.

The crossover row — when the loan starts working for you

Scan down for the first row where principal exceeds interest. On this loan it is payment #228:

Nineteen years before the majority of each payment reduces your debt. Extra principal payments move this row earlier, which is the clearest way to see their effect.

The last row — the true cost

The final row's cumulative interest is what the loan actually cost you. On this schedule: $486,632 on a $400,000 loan. Total paid, $886,633. If your schedule has no cumulative column, multiply the payment by the number of payments and subtract the loan amount.

A schedule tells you three things you cannot easily get anywhere else:

• How much you still owe at any future date. Find the row for the month you plan to sell — that balance is roughly what you will need to pay off.
• When you will hit 20% equity. Find the row where the balance drops to 80% of your home's value. On a loan that started at 90% LTV, that is payment #92 — about 7 years 8 months in — which is when you can usually request PMI cancellation.
• How much interest you paid in a tax year. Sum the interest column for those twelve rows, or read the cumulative column at each year end. This should match the Form 1098 your servicer sends.

A schedule with extra payments has an additional column — usually "extra principal" or "additional principal" — and behaves differently in one telling way:

Watch row 2. The extra payment did not only add $200 — it also moved $1.05 from the interest column into the principal column, because the balance it was calculated on was smaller. The schedule also gets shorter: 294 rows instead of 360.

A few dollars of drift is normal and does not mean anything is wrong:

• Rounding. Interest is rounded to the cent every month, 360 times. Small differences accumulate.
• Payment timing. Some servicers calculate interest daily rather than monthly, so paying on the 1st versus the 15th shifts the numbers slightly.
• Escrow. Your statement shows the full bill; the schedule shows only principal and interest.
• The first payment. Closing usually collects prepaid interest for the partial first month, so payment one can look irregular.
• Rate changes. On an adjustable-rate mortgage the schedule is recalculated at every reset — any schedule printed before a reset is obsolete after it.