Repayment after the 2025 law · calculator
Student loan interest calculator
A $27,000 undergraduate balance at the 2026-27 rate of 6.52% accrues about $4.82 of interest a day, or $147 a month. Federal Direct Loans charge simple interest that accrues daily on the principal, and interest is not charged on interest until it is capitalized. The rate is fixed for the life of each loan and set by the year of its first disbursement: 6.52% for undergraduate loans, 8.07% for graduate unsubsidized loans and 9.07% for PLUS loans first disbursed from July 1, 2026 to June 30, 2027. Interest matters most when no payment is due. Unsubsidized and PLUS loans accrue it from the first disbursement, through school and the grace period, while subsidized loans do not charge you interest during school at least half time. On the Repayment Assistance Plan the picture changes again, because interest that an on-time payment does not cover is waived. This calculator gives the daily and monthly figure for any balance and rate, and the total for a period without payments.
Interest per month
$147
About $4.82 a day on $27,000
| Interest over 6 months without payments | $880 |
| 10-year standard payment afterwards | $307 |
| Interest paid in the first year of that plan | $1,702 |
Simple interest accrued daily on principal, about the yearly rate ÷ 365 per day; your servicer's daily factor can differ slightly. A subsidized loan does not charge you interest while you are in school at least half time. How this is calculated.
How much interest a federal loan charges each day and each month, and how much piles up while no payment is due.
Checked by Radif Partners · Editorial policy · How we calculate
What builds up before the first bill
Interest on unsubsidized loans runs through the years of study and the six-month grace period. The table estimates it on one year's loan at the 2026-27 rates, from disbursement to the first payment, using simple interest and no payments in between.
| Loan | Rate | Amount | Interest after 4 years and 6 months | After 2 years and 6 months |
|---|---|---|---|---|
| Undergraduate unsubsidized | 6.52% | $2,000 | $587 | $326 |
| Graduate unsubsidized | 8.07% | $20,500 | $7,445 | $4,136 |
| Parent PLUS | 9.07% | $10,000 | $4,081 | $2,268 |
The grace period alone costs a graduate borrower with $41,000 of unsubsidized loans about $1,654. Paying that interest during the six months, even in small amounts, keeps it from turning into principal at the next capitalization event.
Interest on the new plans
Interest is computed the same way on every plan; what differs is what happens when the payment falls short. On IBR the shortfall accrues. On the Repayment Assistance Plan it is not charged when the payment arrives on time (34 CFR 685.209(h)(4)). A borrower with $27,000 at 6.52% and an income of $24,000 pays $40 on RAP while $147 of interest accrues each month: the difference is waived, and the Department also cuts principal by up to $50. The waiver and matching payment page walks through a full month.
Where the rate comes from
Each year the rate for new loans equals the high yield of the 10-year Treasury note sold at the last auction before June 1, plus a fixed add-on: 2.05% for undergraduates, 3.6% for graduate unsubsidized loans and 4.6% for PLUS loans, with caps of 8.25%, 9.5% and 10.5%. The May 12, 2026 auction yielded 4.47%, which produced the 2026-27 rates (Federal Register, September 10, 2026). The interest rate page compares the last four years.
Reading your servicer statement
Each statement splits the last payment between interest and principal and shows the interest accrued but not yet paid. If that unpaid figure grows from month to month, your payment is below the interest, which happens on IBR with a low income or during a forbearance. If it stays at zero and principal falls, your plan is amortizing the loan. Compare the interest line with the monthly figure this calculator gives for your balance and rate: a large gap usually means several loans at different rates, or interest capitalized earlier that raised the principal.
Lowering what you pay in interest
Three levers exist on federal loans: auto pay, which cuts the rate by 0.25% and by 1% in total under the offer open until December 31, 2026; paying interest during school and grace; and prepaying principal, measured by the payoff calculator. Refinancing with a private lender can lower the rate but ends access to federal plans and forgiveness, as the refinance calculator shows.