calculate-loan

01 Loan payments

Student Loan Monthly Payment Calculator and Formula

Calculator No. 01-1755 · Updated · Formula and assumptions shown below

Monthly payment $405.53
Total interest
$4,331.67
= Monthly payment × loan term × 12 − loan amount
Loan amount
$20,000
Input
Interest rate (APR)
8 %
Input
You enter
Loan amount ($), Interest rate (APR) (%), Loan term (years)
You get
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.

This student loan monthly payment calculator estimates the fixed monthly payment and total interest for a loan with a constant APR and repayment term. Enter the principal, annual interest rate, and term in years to see the estimated payment; it models standard amortizing-loan arithmetic, not a particular repayment program.

Formula

The calculator uses the standard fixed-payment amortization formula. It converts the annual percentage rate to a monthly rate, then finds the payment that pays interest and reduces principal over the selected number of months:

Monthly payment = P × r ÷ [1 − (1 + r)−n]

  • P is the starting loan principal, in dollars.
  • r is the monthly interest rate as a decimal: APR ÷ 1200. For an 8% APR, r = 8 ÷ 1200.
  • n is the number of monthly payments: term in years × 12.

Total interest is calculated as the rounded monthly payment multiplied by the number of payments, minus the original principal: total interest = monthly payment × n − P. The monthly payment is rounded to cents for display, and the total uses that displayed payment. Actual loan servicing may calculate interest or payments differently.

Worked Example

Using the calculator’s default values—$20,000 principal, 8% APR, and a five-year term—the monthly rate is 8 ÷ 1200 = 0.0066667, and the number of payments is 5 × 12 = 60.

Substitute those values into the payment formula:

$20,000 × 0.0066667 ÷ [1 − (1.0066667)−60] = $405.53 per month, rounded to the nearest cent.

Total of rounded payments = $405.53 × 60 = $24,331.80. Estimated total interest = $24,331.80 − $20,000 = $4,331.80.

Assumptions

  • The interest rate stays fixed for the full term.
  • Payments are equal, made monthly, with the first payment one month after the starting balance is established.
  • Interest is modelled monthly using APR divided by 12.
  • Fees, taxes, insurance, payment pauses, late charges, and other costs or changes are not included.

What the Estimate Tells You

The monthly payment is the amount required by this simplified model to repay principal and interest in equal installments. Early payments include a larger interest portion because interest is calculated on a higher remaining balance; over time, more of each payment reduces principal. The total-interest figure estimates the interest across all scheduled payments, not the total amount borrowed or the monthly payment alone.

Use a principal amount that reflects the balance you actually want to model. If you are estimating a new loan, the amount borrowed may differ from the amount applied to tuition or other expenses because the contract can include charges or adjustments. Get the precise principal, APR, and repayment term from the loan documents or servicer rather than relying on a generic example.

Using the Calculator Carefully

  • Enter APR as a percentage per year. Type 8 for 8%, not 0.08. The calculator divides the entered percentage by 1200 to obtain a monthly decimal rate.
  • Enter the term in years. Five years means 60 monthly payments. If your documents show a term in months, divide that number by 12 before entering it.
  • Check the repayment structure. This formula assumes level monthly payments and a constant rate. It does not represent every loan arrangement.
  • Use sufficient precision. The payment is displayed to cents, so a small rounding difference can affect the total interest, particularly over many payments.

The calculator accepts a positive APR because its formula divides by the monthly rate. A zero-interest loan requires a different calculation: principal divided by the number of payments. For example, $20,000 over 60 equal payments at zero interest would be $333.33 per month before any contract-specific adjustments.

Student Loan Details the Formula Leaves Out

A calculator based on principal, APR, and term cannot determine what repayment options apply to a specific student loan. Different loans or repayment arrangements may have changing rates, different required payments, deferment or forbearance periods, income-based calculations, or other features. These are not represented by the fixed-rate formula. Check the loan agreement and ask the servicer or relevant program about terms that affect the actual bill; program rules are not modelled here.

Likewise, an extra payment can change the payoff timeline and total interest, but this calculator assumes only the scheduled equal payment. It does not determine how an extra amount is allocated or whether the servicer applies it to principal, future installments, or another balance. For a payoff estimate, use the current balance, the applicable rate, payment history, and the servicer’s method—not just the original loan amount.

Frequently Asked Questions

How do I calculate a student loan payment?
Use the amortizing-payment formula with the current principal, monthly rate (APR ÷ 1200), and total monthly payments (years × 12). This calculator performs that arithmetic and displays the payment and estimated total interest.

Does the calculator include federal or income-driven repayment plans?
No. It calculates a fixed payment for a constant rate and term. It does not apply program eligibility, payment formulas, forgiveness provisions, or other rules. Confirm those details with the servicer or the program.

Why does my bill differ from this estimate?
The actual amount can reflect a different balance, rate, term, payment date, fees, rounding method, or repayment arrangement. Compare the calculator inputs with your current loan documents and ask the servicer to explain any difference.

Can I use this for several student loans?
You can estimate each loan separately using that loan’s principal, APR, and term, then add the estimated payments. A combined estimate assumes each loan follows the same fixed-payment model and does not account for account-level billing details.

Does total interest mean the full amount I will pay?
No. Total interest is the estimated amount above principal under the model. The total of scheduled payments is principal plus interest; fees and other costs are excluded.

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 pmt | Monthly payment | $ | p * (apr / 1200) / (1 - (1 + apr / 1200) ^ -(yrs * 12)) | 2
out int | Total interest | $ | pmt * yrs * 12 - 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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