calculate-loan

01 Loan payments

Total Loan Cost Calculator and Formula

Calculator No. 01-6254 · Updated · Formula and assumptions shown below

The calculator on this page is switched off while it is checked. The formula is below, and the worked example shows how to do the sum by hand.

Estimate for education, not financial advice. The result follows from the numbers you enter and the formula shown. It is not a quote or an offer, and it does not include fees, taxes or insurance unless the calculator asks for them. Ask your lender for the exact figures.

This calculator estimates the total of the scheduled monthly payments on a fixed-rate loan, using the loan amount, annual percentage rate (APR), and term you enter. It also shows the monthly payment and total interest, so you can see how the total cost is built up.

Formula

Total loan cost here means the sum of all scheduled payments, not just the amount borrowed and not necessarily every expense associated with borrowing. The calculator uses a standard fixed-rate, fully amortizing loan formula:

  • Monthly payment: M = round[P × r / (1 − (1 + r)−n), 2]
  • Total payments: T = M × n
  • Total interest: I = T − P

P is the starting loan principal in dollars; APR is the annual percentage rate entered as a percent; r is the monthly rate, APR ÷ 1,200; n is the number of monthly payments, years × 12; M is the monthly payment in dollars rounded to cents; and T and I are total payments and total interest in dollars. Because the total uses the rounded monthly payment, it represents the sum of the displayed installments.

Worked Example

Using the calculator’s default values—$20,000 principal, 8% APR, and a five-year term—the number of payments is 5 × 12 = 60, and the monthly rate is 8 ÷ 1,200 = 0.0066667.

  1. Apply the payment formula: M = 20,000 × 0.0066667 ÷ [1 − (1.0066667)−60].
  2. The monthly payment is $405.53 when rounded to the nearest cent.
  3. Total payments are $405.53 × 60 = $24,331.80.
  4. Total interest is $24,331.80 − $20,000 = $4,331.80.

The headline result is $24,331.80, the scheduled payment total for these inputs. It is not $24,331.80 of interest: $20,000 repays principal, while $4,331.80 is the interest implied by the model.

Assumptions

  • The interest rate stays fixed for the entire term.
  • There are equal monthly payments, made at the end of each monthly period.
  • Interest accrues monthly using the APR divided by 12; the calculator uses APR ÷ 1,200 as the monthly decimal rate.
  • The loan is fully repaid by the final scheduled payment, with no extra payments or missed installments.
  • Fees, taxes, insurance, PMI, escrow, and other charges are not included unless represented in the loan amount or rate you enter. The calculator does not separately model them.

What Total Loan Cost Includes

The result is the arithmetic total of the regular payments under the inputs, including repayment of principal and the interest calculated by the formula. It is useful for understanding the overall scheduled outlay under those assumptions. It should not be read as a complete quote of the cost of borrowing: charges outside the payment schedule may increase the amount paid, and a variable rate or changing payment can make the actual total different.

For example, changing the loan term changes both the payment count and the amount of time interest accrues. A longer term commonly produces more scheduled payments, while a shorter term produces fewer; the monthly amount also changes. The exact effect depends on the principal and APR. To compare two scenarios meaningfully, enter the same principal and use the rates, terms, and applicable charges actually disclosed for each scenario.

How to Use and Interpret the Estimate

Enter the amount borrowed, APR as a percentage per year, and term in years. The displayed payment is monthly, and the total is that rounded payment multiplied by the total number of months. For instance, enter 8 for an 8% APR, not 0.08 or 8.00 as a decimal fraction. The calculator permits terms as short as one month and uses years as the term unit.

APR and the interest rate used in a payment calculation are related but may not describe every aspect of a particular loan in the same way. The calculator treats the entered APR as a fixed nominal annual rate divided into monthly periods. It does not independently reconcile a lender’s disclosures, fees, or rate conventions. Use the figures supplied for the specific loan and check what each quoted figure includes.

Rounding is important: the monthly installment is rounded to cents before it is multiplied by the number of payments. A lender may handle the final installment or rounding adjustments differently, so a small difference from an official repayment schedule can occur. The total also assumes every scheduled payment is made on time and in the same amount.

Limits and Common Misunderstandings

  • Total cost is not total interest. Total payments include returning the borrowed principal. Interest is shown separately as total payments minus principal.
  • The estimate is not a payoff quote. A payoff amount on a particular date can account for accrued interest, payment timing, fees, or other contract details that this calculator does not know.
  • Not all borrowing expenses are in the monthly payment. Application or origination charges, insurance, taxes, and other costs are excluded unless included in the inputs. Check the loan’s disclosure for the actual items and amounts.
  • Changing terms or rates changes the result. A variable-rate loan cannot be represented accurately by one fixed APR over its full term if its rate changes.

This tool is estimate arithmetic for educational purposes, not financial advice. For exact payment dates, fees, and amounts, refer to the lender’s disclosure and repayment schedule. The result is an estimate, and the lender’s disclosure gives the exact figures.

Frequently Asked Questions

How do you calculate total loan cost?
For this fixed-rate estimate, calculate the monthly payment, round it to cents, then multiply by the number of monthly payments. The result includes principal and modeled interest.

Is total loan cost the same as total interest?
No. Total loan cost in this calculator is the sum of payments. Total interest is that sum minus the original loan principal.

Does this calculator include loan fees?
No. It calculates scheduled payments from the amount, APR, and term entered. Fees and other charges are excluded unless reflected in those inputs.

Why might my lender’s total be different?
The contract may include fees, a different rate convention, irregular payment dates, a final-payment adjustment, or other details not modeled here. Compare the calculator’s assumptions with the lender’s disclosure.

Can I use this for a variable-rate loan?
Only as a simplified scenario using one assumed fixed rate. If the rate changes during repayment, the actual payment schedule and total can differ.

Related

Formula used
in p | Loan amount | $ | 20000 | 1 | 100000000
in apr | Interest rate (APR) | % | 8 | 0.01 | 100
in yrs | Loan term | years | 5 | 0.0833 | 50
out tot | Total payments (loan cost) | $ | pmt * yrs * 12 | 2
out pmt | Monthly payment | $ | round(p * (apr / 1200) / (1 - (1 + apr / 1200) ^ -(yrs * 12)), 2) | 2
out int | Total interest | $ | tot - p | 2

Each line is one input (in, sel, list) or one result (out: label, unit, formula, decimals). How the calculators work

Method: the standard loan formula for this calculation, fixed rate and monthly compounding unless stated, rounded as each result states. Not financial advice; no lender, rate or product is recommended. See formulas and assumptions, the disclaimer or report an error.

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