Daily Student Loan Interest Calculator

This calculator works out how much interest a student loan balance builds up each day, over a period such as a month or a grace period, and over a year. Enter the balance, the interest rate and the number of days.

Formula

Daily interest = balance × rate ÷ 100 ÷ 365. Interest for d days = daily interest × d (simple daily interest, not compounded).

Worked Example

A $30,000 balance at 5.5%, over 30 days.

1. Daily interest = 30,000 × 0.055 ÷ 365 = $4.5205
2. 30 days = 4.5205 × 30 = $135.62
3. A year = 30,000 × 0.055 = $1,650.00

Assumptions

• Simple daily interest on the balance, 365-day year (a lender may use a different day count).
• The balance does not change during the period (no payments, no capitalization).
• Program rules such as subsidies, deferment or capitalization dates are not modelled.

How to read the result

Interest that is not paid can be added to the balance at certain points (capitalized), after which interest is charged on it too. Your servicer’s statement shows when that happens for your loan.

Limits and common mistakes

• The result for the period is rounded only at the end; the servicer may round each day.
• Enter the rate for this loan; each loan of several can have its own rate.

Frequently Asked Questions

How much interest does $30,000 at 5.5% build up per day?

About $4.52 a day, about $135.62 a month of 30 days.

Why does my statement show a slightly different figure?

The day count, rounding and the exact balance each day can differ.

Does daily interest compound?

Not in this calculation; it is simple daily interest on the balance.

in b | Loan balance | $ | 30000 | 0 | 10000000
in apr | Interest rate | % | 5.5 | 0 | 100
in d | Days in the period | days | 30 | 1 | 3660
out di | Daily interest | $ | b * apr / 100 / 365 | 4
out per | Interest for the period | $ | di * d | 2
out yi | Interest for a year | $ | b * apr / 100 | 2