Daily Payment Amortization Schedule Calculator

A daily payment amortization schedule shows how each daily payment is divided between interest and principal, and how the loan balance changes over time. This calculator estimates the level daily payment needed to repay a fixed-rate loan over the entered term, using the principal, annual APR, and term to calculate the payment and total interest.

Formula

The calculator uses a fixed-payment amortization formula with a daily periodic rate. It assumes 365 payment periods per year and rounds the calculated daily payment to the nearest cent before estimating total interest.

• Daily payment = round[ P × r / (1 − (1 + r)^−N), 2]
• Daily rate, r = APR / 36,500
• Number of payments, N = term in years × 365
• Total interest = daily payment × N − P

P is the loan principal in dollars, APR is the annual percentage rate entered as a percentage, r is the daily interest rate as a decimal, and N is the number of daily payments. For example, an APR of 8% becomes 8 / 36,500 per day under this model. A real loan may define its daily rate or day count differently.

Worked Example

Using the calculator’s defaults—$20,000 principal, 8% APR, and a 5-year term:

1. Convert the APR to a daily rate: 8 / 36,500 = 0.000219178.
2. Calculate the payment count: 5 × 365 = 1,825 daily payments.
3. Apply the amortization formula: $20,000 × 0.000219178 / [1 − (1 + 0.000219178)^−1,825] = about $12.26 per day, rounded to the nearest cent.
4. Estimate total payments using the rounded payment: $12.26 × 1,825 = $22,374.50.
5. Subtract principal: $22,374.50 − $20,000 = $2,374.50 estimated total interest.

The displayed payment is an estimate to the cent. Because a rounded daily payment may not repay the balance exactly after the final scheduled payment, an actual lender may adjust the final amount. The total-interest output follows the calculator’s stated rounded-payment method.

Assumptions

• The interest rate is fixed for the whole term.
• Payments are equal, made once per day, with the first payment one daily period after borrowing.
• Interest accrues at APR divided by 365, with daily periods; this is a simplified daily-rate convention, not a lender-specific day-count calculation.
• Fees, taxes, insurance, late charges, payment holidays, and other loan terms are not included.

How a Daily Schedule Works

In an amortizing loan, each payment covers the interest accrued for that period and reduces some principal. Early in repayment, the outstanding balance is larger, so the interest portion is generally larger. As the balance falls, less interest accrues and more of the same scheduled payment goes toward principal. A schedule repeats that calculation for each period until the balance is paid.

For a daily schedule, the basic sequence is:

1. Start with the opening balance.
2. Calculate that day’s interest by multiplying the balance by the daily rate.
3. Subtract the interest from the payment to find the principal reduction.
4. Subtract that principal reduction from the opening balance to get the new balance.

For example, with a $20,000 opening balance at the example daily rate, one day’s approximate interest is $20,000 × 0.000219178, or about $4.38. A $12.26 payment would therefore reduce principal by about $7.88 that day. Actual schedules can differ due to rounding and the contract’s accrual rules.

Daily Payments Versus Daily Interest

“Daily amortization” can refer to two different things: payments made every day, or interest calculated each day while payments are made on another schedule. They are not interchangeable. A loan might accrue interest daily but require monthly payments; in that case, the borrower does not make 365 payments each year, and this calculator’s daily-payment formula does not represent the payment schedule.

Check the agreement or lender-provided disclosure for payment frequency, how interest accrues, and the number of days used in a year. Depending on the contract, interest may be calculated using a 365-day or 360-day basis, or other specified rules. A 360-day basis generally produces a different interest calculation from a 365-day basis, so applying the wrong convention can make an estimate diverge from the actual ledger.

Reading the Results and Common Errors

The first result is the estimated payment for each day, not a monthly payment or an amount due each business day. The total-interest estimate assumes every scheduled payment is made on time and exactly at the calculated frequency. To compare it with a monthly budget, multiplying the daily payment by 30 is only a rough conversion; months have different lengths, and the loan may not accept daily payments.

• Confusing APR with the daily rate: enter APR as a yearly percentage, such as 8, not as 0.08 or a daily percentage.
• Assuming every day is a payment day: the output uses 365 payments per year, including a simplified treatment of weekends and holidays.
• Ignoring payment rounding: cents-rounding each payment can leave a small balance or require a different final payment.
• Using the result as a payoff quote: a payoff figure may include interest through a particular date and other contract-specific amounts not represented here.

When to Use This Estimate

This calculation is useful for understanding the mathematics of a loan that truly has equal daily payments, or for seeing how principal, APR, and term affect a modeled daily installment. It is not a substitute for a lender’s amortization table. If a loan has weekly, biweekly, or monthly installments, calculate it with the matching payment frequency rather than treating daily interest accrual as daily repayment.

To build or verify a full schedule, record the opening balance, interest for the period, payment, principal paid, and closing balance for every period. Use the lender’s stated accrual convention and payment dates. If the payment is less than the interest due for a period, the balance may not decline as expected; this fixed-payment estimate does not model missed or insufficient payments.

Frequently Asked Questions

What is a daily payment amortization schedule?
It is a period-by-period record of a loan’s daily payments, accrued interest, principal reduction, and remaining balance, based on the loan’s terms and calculation rules.

Does daily interest mean I have to pay every day?
No. Daily interest describes how interest may accrue. Payment frequency is a separate term, so a loan can accrue interest daily while requiring payments weekly or monthly.

Why does the lender’s payment differ from this result?
The contract may use a different day-count convention, payment date, compounding method, rounding practice, fee treatment, or final-payment adjustment. Compare the estimate with the lender’s disclosed schedule.

Can I use this calculator for monthly payments?
No. It assumes 365 equal daily payments per year. A monthly loan needs a formula based on monthly periods and the monthly rate specified for that calculation.

Does making extra payments reduce total interest?
When extra amounts are applied to principal, they can reduce the balance on which later interest accrues. The effect depends on the loan’s terms and how the payment is applied; this calculator does not model extra payments.

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

Related

• Payment in Kind Interest Calculator and Explanation
• Amortization Calculator: Principal Payment Explained
• Amortization Calculator With Extra Payments

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 | Daily payment | $ | round(p * (apr / 36500) / (1 - (1 + apr / 36500) ^ -(yrs * 365)), 2) | 2
out int | Total interest | $ | pmt * yrs * 365 - p | 2