How to Read a Commercial Mortgage Amortization Schedule
A commercial mortgage amortization schedule shows how each payment divides between interest and principal, and how much principal remains afterward. To read it correctly, reconcile one payment row, check totals across the relevant period, and locate the contractual maturity date. Do not assume the last row in a long projection is the date your loan actually ends.
This tutorial uses a hypothetical $1 million loan at a fixed 6% nominal annual rate, with 25-year amortization and a five-year term. Payments occur at month end. There are no fees, escrows, prepayments, or interest-only periods. The figures are educational examples, not a lender repayment schedule, payoff quote, or personalized financial advice.
In this guide: Schedule columns · First payment · Later rows · Maturity · Schedule audit
What a commercial mortgage amortization schedule shows
Payment number, opening balance, payment, interest, principal, and closing balance
A schedule is a sequence of linked calculations. Each row starts where the previous row ended.
- Payment number: the installment’s position in the sequence.
- Opening balance: principal outstanding before that payment.
- Payment: the regular P&I installment.
- Interest: opening balance multiplied by the periodic rate in this model.
- Principal: payment minus interest.
- Closing balance: opening balance minus principal.
Dates add the calendar context. Payment number 12 means the twelfth modeled payment, not necessarily the end of a calendar tax or reporting year. For the underlying definitions, review how CRE loan amortization works.
[IMAGE: Commercial mortgage amortization schedule with payment number, opening balance, interest, principal, and closing balance labeled.]Amortization projection versus the contractual repayment schedule
Our payment is calculated across 300 months, but the hypothetical loan matures after 60 monthly payments. A projection could continue for all 300 rows to demonstrate full amortization. Rows after 60 would not establish a right to continue making installments beyond the five-year maturity.
Before interpreting a supplied table, ask what it represents: an educational projection, a current contractual schedule, or an earlier model based on superseded assumptions. A correct calculation with the wrong starting balance or dates is still the wrong schedule for the task.
How to read the first payment row step by step
Calculate interest from the opening balance
The monthly rate is 6% ÷ 12 = 0.5%, or 0.005 in decimal form. First-month interest is therefore:
$1,000,000 × 0.005 = $5,000.00.
The rate and balance must belong to the same period. This simplified model does not calculate interest by counting actual days. If the loan documents require daily accrual or an irregular opening period, that needs a compatible schedule rather than an unexplained adjustment to this row.
Subtract interest to find principal and the closing balance
The example’s regular payment is $6,443.01. You can calculate the principal-and-interest payment separately; the task here is to audit how that payment is applied.
Subtract $5,000.00 of interest to obtain $1,443.01 of principal. Subtract that principal from $1 million to obtain a closing balance of $998,556.99.
These two checks should agree:
- Interest + principal = payment.
- Opening balance − principal = closing balance.
The next opening balance must also equal this closing balance. If it does not, look for an additional advance, prepayment, adjustment, or spreadsheet reference error. Do not assume a missing bridge is harmless just because the regular payment looks familiar.
How principal and interest change across the loan term
Compare early rows with later rows
The following excerpt contains selected, nonconsecutive rows, not the complete schedule. Values are calculated with internal precision and then rounded to cents.
| Payment | Opening balance | P&I payment | Interest | Principal | Closing balance |
|---|---|---|---|---|---|
| 1 | $1,000,000.00 | $6,443.01 | $5,000.00 | $1,443.01 | $998,556.99 |
| 2 | $998,556.99 | $6,443.01 | $4,992.78 | $1,450.23 | $997,106.76 |
| 12 | $983,724.00 | $6,443.01 | $4,918.62 | $1,524.39 | $982,199.61 |
| 60 | $901,257.59 | $6,443.01 | $4,506.29 | $1,936.73 | $899,320.87 |
The regular payment stays level, but principal repayment rises as interest declines. Row 60 is not a new payment formula; it is the same calculation applied to a smaller opening balance.
Independent rounding means some displayed components differ by one cent from their displayed total. For example, row 60’s displayed interest and principal sum to $6,443.02, while its unrounded components sum exactly to the unrounded payment. A lender schedule using contractual cent-rounding may reconcile differently. Keep the chosen convention explicit.
Reconcile annual totals and cumulative principal reduction
Annual interest is the sum of interest from all included rows. It is not the last month’s interest multiplied by 12. The same rule applies to principal.
| Measure | Payments 1–12 | Payments 1–60 |
|---|---|---|
| Scheduled P&I paid | $77,316.17 | $386,580.84 |
| Interest paid | $59,515.78 | $285,901.71 |
| Principal repaid | $17,800.39 | $100,679.13 |
| Ending principal balance | $982,199.61 | $899,320.87 |
For the first year, $1,000,000 minus $17,800.39 equals the displayed ending balance. Across five years, subtract cumulative principal of $100,679.13 instead. This balance-change check can reveal an omitted row even when individual rows appear reasonable.
Each complete 12-payment year has the same total P&I under these constant-payment assumptions. Its interest and principal totals change. Annual reporting therefore needs both the period boundaries and the component sums, not just the regular payment.
How to identify the balance due at maturity
Locate payment 60 in a five-year-term example
Find the row corresponding to the last regular payment in the contractual term. In this illustration, that is payment 60. Its closing balance is $899,320.87.
[IMAGE: Commercial mortgage schedule highlighting the $899,320.87 balance after the 60th regular payment in the example.]The opening balance on that row is $901,257.59. Using it as the post-payment balloon would fail to account for the principal included in installment 60. The row label and the before-versus-after convention matter as much as the dollar amount.
Separate the regular installment from the residual balloon
The final regular installment is $6,443.01; the residual after it is $899,320.87. If settled together under this illustration, those displayed components total $905,763.88, before any additional contractual amounts.
That sum remains an illustrative calculation, not a payoff statement. A real payoff is date-specific and must reflect the actual loan terms, payments, interest accrual, and applicable charges. A lender-confirmed payoff statement and a modeled closing principal balance serve different purposes.
Keeping the two components separate also prevents double counting. A property model that already includes installment 60 should add the post-installment residual—not an amount that already contains the same installment again.
How to build and audit a repayment schedule
Confirm rate, dates, payment frequency, and rounding
Begin with a clearly labeled assumptions area: original or current principal, nominal rate, payment frequency, amortization months, term months, and first modeled payment date. State whether the model begins at origination or at a later point in the loan.
Compare the calendar dates with the modeled periods. Twelve payments need not match a calendar year if the first installment falls partway through it. Maintain internal precision if following this tutorial, and round only display values. Do not mix that approach with a cent-rounded contractual schedule without explaining the reconciliation.
Flag IO periods, resets, prepayments, and irregular accrual
A fixed-rate monthly schedule does not automatically accommodate an interest-only phase, changing rate, voluntary principal payment, daily interest calculation, or irregular interval. Each changes one or more row inputs or rules.
When a schedule and loan document disagree, first identify the structure being modeled. Changing the regular payment to force a desired final balance can conceal the actual issue rather than resolve it.
A spreadsheet row structure and balance checks
Put the periodic rate and regular payment in fixed assumption cells. In the first row, reference starting principal. Calculate interest, principal, and closing balance in that order. In every later row, reference the previous closing balance as the new opening balance.
When copying formulas down:
- Keep assumption references fixed where appropriate.
- Let the preceding-balance reference advance one row at a time.
- Check that payment numbers and dates advance consistently.
- Sum the exact rows in the reporting period.
- Reconcile cumulative principal with the change in balance.
- Mark maturity and stop contractual interpretation at that point.
When to use the calculator or request lender confirmation
An independently calculated schedule can provide a useful cross-check, but agreement between two simplified models does not confirm contractual accuracy. Compare assumptions before comparing outputs, and obtain lender clarification when dates, accrual, or payoff requirements remain uncertain.
FAQ
Why does a 25-year projection show a five-year balance?
Amortization determines the payment calculation; the five-year term sets the earlier maturity checkpoint. Regular payments have not fully repaid principal by that point.
Can I calculate annual interest from the December row?
Not by multiplying that row by 12. Sum the interest amounts for the actual payments included in the reporting year.
Which balance is the modeled balloon?
Here it is the closing principal balance after payment 60, not that row’s opening balance or the regular installment itself.
Does this guide provide a lender-approved schedule?
No. It teaches a reproducible educational model. Actual payment and payoff obligations require confirmation from the relevant documents and lender.