Mortgage Amortization Schedule

A mortgage amortization schedule shows each projected payment's principal, interest, and remaining-balance allocation.

A mortgage amortization schedule is a payment-by-payment table showing the projected principal, interest, and remaining balance under a stated set of loan assumptions.

Why It Matters

The schedule turns a long mortgage into a visible repayment map. It shows that a level P&I payment can have a changing internal allocation, with more interest and less principal near the beginning and the reverse near the end.

Borrowers can use the schedule to compare terms, estimate balance at a future date, understand total interest, and model extra principal payments. It is especially useful when two loans have similar starting payments but different rates or repayment periods.

An amortization schedule is still a model, not a substitute for the servicer’s current account records. Payment timing, rounding, rate adjustments, extra payments, modifications, and fees can cause the actual account to differ from an original schedule.

Where It Appears in the Borrower Process

Schedules commonly appear in lender illustrations, mortgage calculators, loan-comparison worksheets, and post-closing payoff planning. A borrower may request one from the lender or generate one from the note amount, rate, payment frequency, and amortization period.

After closing, the borrower can compare the projected balance with the principal balance on the mortgage statement. A difference is not automatically an error, but it should be understood: extra principal, different effective dates, payment application, or loan changes may explain it.

Core Schedule Calculations

For a simplified fixed-rate mortgage with monthly payments, each row follows three relationships:

$$ I_t = B_{t-1} \times r $$
$$ P_t = M - I_t $$
$$ B_t = B_{t-1} - P_t $$

Where:

  • I_t is interest for payment period t
  • B_{t-1} is principal before that payment
  • r is the periodic interest rate
  • P_t is principal applied by that payment
  • M is the scheduled P&I payment
  • B_t is principal remaining after the payment

Actual servicing follows the note and account rules, including applicable day-count, timing, and rounding conventions.

Practical Example

For a $300,000, 30-year fixed-rate mortgage at 6.5%, the scheduled monthly P&I is about $1,896.20. Selected rows from a simplified schedule look like this:

PaymentP&IInterestPrincipalBalance after payment
1$1,896.20$1,625.00$271.20$299,728.80
2$1,896.20$1,623.53$272.67$299,456.12
12$1,896.20$1,608.40$287.81$296,646.82
180$1,896.20$1,182.95$713.25$217,677.42
360$1,896.20$10.22$1,885.99$0.00*

* The final row is rounded for illustration. A real final payment can vary slightly because of calculation and rounding conventions.

The table makes the amortization mechanism visible: the payment stays level while the interest column shrinks and the principal column grows.

Reading a Schedule Carefully

QuestionWhat to verify
Is the starting balance correct?Use the note amount, not the purchase price or cash to close
Is the rate fixed for the full projection?An ARM schedule may change when the rate and payment reset
Does the payment include escrow?An amortization table usually models P&I, not taxes and insurance
Are extra payments included?Optional principal can shorten the schedule materially
Does the term match the amortization period?A balloon loan can show a remaining balance at maturity
Is this projection current?A modification, recast, or prior extra payment can make an old table stale

How It Differs From Nearby Terms

Amortization is the repayment process. The schedule is the numerical table that represents it.

A Payment Schedule focuses on when payments are due and how often they occur. An amortization schedule adds the projected allocation and remaining balance for each period.

A Mortgage Statement reports the current account. The amortization schedule projects a longer path from assumed terms.

A Payoff Statement provides a date-specific amount needed to satisfy the loan. The balance in an amortization table does not include every amount that can appear in a payoff quote.

Knowledge Check

  1. Why does the principal column usually increase on a level-payment fixed-rate schedule? The declining balance produces less interest, leaving more of the same P&I payment for principal.
  2. Is the balance in an amortization schedule always the mortgage payoff amount? No. A payoff is date-specific and can include accrued interest and other amounts not shown in the projected principal balance.
  3. Why can an actual statement balance differ from an original schedule? Payment timing, rounding, extra principal, rate changes, recasts, modifications, or other account events can change the path.
Revised on Sunday, August 30, 2026