calculate-loan

01 Loan payments

Total Cost Calculator for Loans

Calculator No. 01-6260 · Updated · Formula and assumptions shown below

Total payments $24,331.80
Monthly payment
$405.53
Level-payment formula, rounded to the cent
Total interest
$4,331.80
= Total payments − loan amount
Loan amount
$20,000
Input
You enter
Loan amount ($), Interest rate (APR) (%), Loan term (years)
You get
Total payments ($), Monthly payment ($), Total interest ($)
Rounding
2 dp

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.

A total cost calculator for a loan estimates the amount repaid over the full term: principal plus interest, using the loan amount, annual percentage rate (APR), and term you enter. It also shows the monthly payment and total interest; actual loan charges can differ if fees or other costs apply.

Formula

The calculator assumes a fixed APR and equal monthly payments. It first calculates the monthly payment, rounds it to the nearest cent, and multiplies that payment by the number of months to estimate total payments.

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

Here, P is the amount borrowed in dollars, APR is the annual percentage rate entered as a percentage, r = APR ÷ 1200 is the monthly rate as a decimal, n is the number of monthly payments (years × 12), M is the monthly payment in dollars, T is total payments in dollars, and I is estimated interest in dollars. For the payment equation, the monthly rate must be greater than zero; this calculator sets the APR minimum at 0.01%.

Worked Example

Using the calculator’s defaults—P = $20,000, APR = 8%, and a five-year term:

  1. Convert APR to a monthly rate: r = 8 ÷ 1200 = 0.0066667.
  2. Convert the term to payments: n = 5 × 12 = 60.
  3. Calculate the payment: M = round[20,000 × 0.0066667 ÷ (1 − (1.0066667)−60), 2] = $405.53.
  4. Calculate total payments using the rounded monthly payment: T = $405.53 × 60 = $24,331.80.
  5. Subtract principal to estimate interest: I = $24,331.80 − $20,000 = $4,331.80.

The calculator’s headline result is $24,331.80 in total payments. Because the monthly payment is rounded to cents, the final payment on an actual loan may be adjusted slightly to clear the remaining balance.

Assumptions

  • The interest rate stays fixed throughout the loan term.
  • Payments are equal, monthly, and made at the end of each period.
  • Interest is compounded monthly using APR ÷ 12.
  • Fees, taxes, insurance, escrow, and other charges are not included unless incorporated into the entered loan amount or APR.

What Total Cost Includes—and Excludes

In this calculator, “total cost” means the sum of modeled loan payments. It includes the borrowed principal and interest calculated under the assumptions above. It does not automatically represent every dollar associated with borrowing. A lender may disclose costs or payment components that this simple calculation does not model, and the timing or structure of payments can affect the result.

For a fuller estimate, check the lender’s written figures and identify which costs are already included. Do not add an item twice: for example, a fee rolled into the loan amount is already part of the principal entered here. If a charge is paid separately, this calculator will not include it unless you account for it outside the displayed result.

When to Use the Calculator

Use it to understand how principal, APR, and repayment length combine mathematically, or to check a lender’s quoted payment against a basic fixed-rate estimate. It can also clarify the difference between the amount borrowed and the total repaid. The result is a calculation, not a statement about approval, affordability, or whether a loan is suitable.

For a useful comparison, enter the same loan amount and use each option’s stated APR and term. Keep in mind that a comparison is only as complete as its inputs: if one offer has costs or payment features not represented by those three numbers, the calculator cannot capture them. Obtain the relevant figures from the lender rather than substituting an assumed rate or fee.

Common Mistakes and Limits

  • Confusing APR with a monthly rate: Enter APR as an annual percentage, such as 8, not 0.08 or a monthly rate. The formula divides the percentage by 1200.
  • Entering the wrong term: The input is years, and the calculator converts it to months. A term of five years means 60 payments.
  • Treating total interest as total cost: Interest is only the amount above principal in this model. Total payments include both principal and interest.
  • Assuming every payment is identical to the cent: Rounding the calculated payment to cents can leave a small balance difference, which may change the final payment.
  • Ignoring loan structure: Variable rates, irregular payments, interest-only periods, payment pauses, or extra payments are not represented by this fixed-payment formula.

The calculation is a useful estimate only when its assumptions resemble the loan being considered. It does not retrieve a rate, quote, fee schedule, or lender-specific payoff amount. For a loan with a zero rate, use principal divided by the number of payments; the standard payment formula shown here is defined for a positive rate.

Frequently Asked Questions

How do I calculate the total cost of a loan?
For a fixed-rate loan with equal monthly payments, calculate the monthly payment from principal, monthly interest rate, and number of payments. Multiply the payment rounded to cents by the number of payments to estimate total payments; subtract principal to estimate interest.

Is total cost the same as total interest?
No. Total payments include repayment of principal as well as interest. In this calculator, total interest is total payments minus the original loan amount.

Does APR include every loan fee?
This calculator does not determine which charges are included in a quoted APR. Check the lender’s disclosure for the specific rate, fees, and payment figures, and use the stated APR as the input.

Why is my lender’s total different?
The lender’s calculation may reflect different payment dates, rounding, fees, rate changes, or loan features. Compare the assumptions and inputs with the lender’s disclosure rather than treating a small difference as an error.

Can I use this for a variable-rate loan?
Only as a simplified estimate for a period with a specified rate. This calculator assumes the APR remains unchanged for the entire term, so it cannot predict later payments if the rate changes.

This result is an estimate, and the lender’s disclosure gives the exact figures.

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 | $ | round(p * (apr / 1200) / (1 - (1 + apr / 1200) ^ -(yrs * 12)), 2) * 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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