Payment on a $300K Student Loan: Monthly Cost

A $300,000 student loan at 6% APR over 10 years has an estimated monthly payment of $3,330.61. Use the calculator to enter the loan balance, APR, and repayment term; it estimates the monthly payment and total interest using fixed monthly payments.

Formula

The calculator uses the standard amortizing-loan payment formula. It treats the APR as a fixed annual rate divided into 12 monthly periods:

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

• P is the starting loan principal, in dollars.
• r is the monthly interest rate, calculated as APR ÷ 1,200. For a 6% APR, r = 0.005.
• n is the number of monthly payments, calculated as years × 12.
• Monthly payment is rounded to the nearest cent before total interest is calculated.

Total interest is estimated as the rounded monthly payment multiplied by the number of payments, minus the original principal: total interest = payment × n − P. This is the interest portion of the modeled payments, not an additional monthly charge.

Worked Example

Using the calculator’s default values—$300,000 principal, 6% APR, and a 10-year term:

1. Convert the APR to a monthly rate: 6 ÷ 1,200 = 0.005.
2. Convert the term to payments: 10 × 12 = 120 months.
3. Apply the payment formula: $300,000 × 0.005 ÷ [1 − (1.005)⁻¹²⁰] = $3,330.61 per month, rounded to cents.
4. Calculate total paid using the rounded payment: $3,330.61 × 120 = $399,673.20.
5. Subtract principal: $399,673.20 − $300,000 = $99,673.20 in estimated total interest.

The payment is an estimate for a fixed-rate loan with equal monthly installments. Actual amounts can differ if the balance, rate, payment schedule, or loan terms change.

Assumptions

• The APR stays fixed throughout the modeled repayment term.
• Payments are equal monthly payments made at the end of each monthly period.
• Interest compounds monthly at APR ÷ 12.
• The calculation excludes fees, taxes, insurance, and other charges. It also does not model deferment, payment pauses, variable rates, or any repayment-program features.

How to Read the Estimate

The first result is the scheduled monthly payment required by the formula to repay the starting balance over the entered term. Total interest estimates how much the modeled payments exceed the original principal. For example, at the defaults, the estimate is $3,330.61 per month and $99,673.20 in interest over 120 payments.

The term and APR both affect the result. Holding the APR and principal constant, a longer term generally lowers the required monthly payment but increases the number of months that interest can accrue. A higher APR generally raises both the monthly payment and total interest for the same term. These are mathematical relationships, not a judgment about which term or rate is suitable for an individual.

For a $300,000 balance, even small differences in the APR or repayment period can materially change the estimate. Enter the rate and term shown in the relevant loan paperwork or ask the servicer for the applicable figures. If the balance includes unpaid interest or fees, use the actual amount being repaid rather than assuming it equals the amount originally borrowed.

Why a Real Student Loan Payment May Differ

A student loan may not follow the calculator’s simple fixed-payment pattern throughout its life. For instance, a loan can have a variable rate, a payment schedule that changes, or a period when regular payments are not being made. Those details can affect the balance and the amount due. This calculator assumes a single fixed APR and immediate, consistent monthly amortization; it does not determine a servicer’s bill or model program-specific terms.

Also, a quoted APR and the rate used to accrue interest may not always be presented in exactly the same way in loan documents. Check the lender or servicer’s disclosure for the rate, repayment term, payment frequency, and any fees included in the balance. For program terms or account-specific options, check directly with the servicer or the relevant program; none are calculated here.

Common Calculation Mistakes and Limits

• Entering the rate as a decimal: Enter 6 for 6%, not 0.06. The calculator converts the annual percentage into a monthly decimal rate.
• Mixing years and months: The term field is in years. Entering 120 would mean 120 years, not 120 payments.
• Assuming the payment is interest only: The formula includes both interest and principal repayment. Early installments contain a larger interest share than later ones, while the total scheduled payment stays level under the assumptions.
• Rounding intermediate figures: The payment is rounded to cents, and total interest uses that rounded payment. A statement may show small differences from daily interest calculations or a final payment adjustment.

The estimate is not a payoff quote, an account statement, or a forecast of a changing-rate balance. It also cannot tell you what payment options apply to a particular student loan. Its purpose is to show the arithmetic for a standard fixed-rate installment loan using the inputs entered.

Frequently Asked Questions

What is the payment on a $300,000 student loan?
It depends on the APR and repayment term. At the calculator’s example inputs of 6% APR and 10 years, the estimated payment is $3,330.61 per month.

How much interest would I pay on $300,000 over 10 years?
At 6% APR with equal monthly payments and the assumptions above, estimated total interest is $99,673.20. A different rate, term, or payment schedule changes the result.

Would a longer repayment term lower the monthly payment?
For the same principal and fixed APR, a longer term generally lowers the scheduled monthly payment while increasing the number of payments. It can also increase total interest because repayment extends over more months.

Does this calculator include student loan repayment programs?
No. It calculates general fixed-rate loan payments only. It does not model eligibility, program-specific payment formulas, forgiveness, or other account terms; check applicable details with the servicer or program.

Why does my bill differ from the calculator?
Your loan may use a different rate, balance, term, payment timing, or calculation method, or include fees or other adjustments. The calculator’s assumptions are simplified; use the servicer’s current account information for an exact amount.

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

Related

• Extra Student Loan Money: Interest and Repayment
• Extra Payment on Principal Loan Calculator
• Extra Student Loan Money Budget Calculator

in p | Loan amount | $ | 300000 | 1 | 100000000
in apr | Interest rate (APR) | % | 6 | 0.01 | 100
in yrs | Loan term | years | 10 | 0.0833 | 50
out pmt | Monthly payment | $ | round(p * (apr / 1200) / (1 - (1 + apr / 1200) ^ -(yrs * 12)), 2) | 2
out int | Total interest | $ | pmt * yrs * 12 - p | 2