Interest paid by year calculator

Find the interest and principal paid during a chosen loan year. Enter the original fixed-rate schedule and select the year counted from the first payment. This tool calculates that year's inclusive payment range and shows its interest total without mixing in payments from other years.

Your interest schedule

Worked example: payments in the second year

The example inputs are from Microsoft CUMIPMT and Microsoft CUMPRINC: an original balance of $125,000, an annual rate of 9%, a 30-year term, and end-of-period monthly payments. The selected range is payments 13 through 24. Figures below are calculated from those inputs and rounded for display.

How it works

P is the original loan balance, N is the number of monthly payments, and A is the constant scheduled payment. For beginning-of-period payments, divide A by (1 + r); the first payment has no interest. With a zero rate, A = P / N and interest is zero. Sum the interest and principal separately across the requested payments.

Microsoft PMT documentation supports constant-payment calculation, and Microsoft CUMIPMT and CUMPRINC define the inclusive payment-range totals. The CFPB amortization explanation describes how the balance and interest portions change. Zero-rate results are an extension here; Excel CUMIPMT and CUMPRINC require a positive rate.

Loan years and calendar years

A loan year here is a group of monthly payment numbers beginning with the first scheduled payment. It is not automatically a January-to-December reporting period. The tool does not ask for a starting date, so it cannot identify which payments landed in a specific tax year or calendar year. If that is your goal, identify the relevant payment numbers from your records and enter them in the payment-range calculator.

The example chooses the second loan year, matching Microsoft's published CUMIPMT example. The start and end numbers are derived from monthly payment grouping. The selected range includes every payment in that group. If a term ends partway through the chosen year, the calculator stops at the last scheduled payment rather than extending the loan beyond its term.

Understand the annual split

Annual interest is the sum of the individual interest portions in that year's range. Annual principal is the sum of the amounts that reduce the modeled balance. Adding those amounts gives the scheduled principal-and-interest payments in the range. Neither subtotal includes costs that are outside the payment formula, such as taxes, insurance, or fees.

When you move from one loan year to another, the scheduled payment amount stays constant under this model. The allocation changes because each prior principal payment reduces the balance used to calculate later interest. The CFPB describes this pattern in its amortization explanation. An annual interest subtotal therefore depends on both the fixed rate and the balance carried into each period.

Use the output with your records

Check the original amount, nominal annual rate, term in months, and timing before comparing the result with a statement. A current balance entered as though it were the original balance describes a new schedule rather than the original loan. If you want to model a remaining schedule, enter the remaining balance and remaining term and treat the first modeled payment as the first payment of that new calculation.

This output is a mathematical schedule, not a tax statement or a determination that interest is deductible. Payment posting dates, daily accrual, rounding, missed installments, or additional principal can affect actual recorded interest. Use your lender's records when you need the amount actually charged or paid. The disclaimer explains the educational purpose of these results.

Build a useful comparison

Calculate one loan year and note its interest and principal amounts. Then change only the year input to inspect a different part of the same schedule. This keeps the original borrowing assumptions constant and makes the changing allocation easier to follow. To see all annual rows at once and the final sum, use the total interest over a loan's life tool. To reproduce a selected year in a spreadsheet, use the CUMIPMT logic tool.

Frequently asked questions

Sources

• Microsoft: CUMIPMT function
• Microsoft: CUMPRINC function
• Microsoft: PMT function
• CFPB: amortization and payment allocation

Data as of 2026-10-05. Source examples and formula documentation only; no live market rates.

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