This Auto Loan Per Diem Calculator helps users understand their daily interest payments based on their loan balance and yearly interest rate. Use the Basic Calculator for direct per diem calculations or switch to the Advanced Calculator to explore the impact of extra payments on daily interest costs.

Auto Loan Per Diem Calculator

Input Field Guide

Each input field has been carefully designed for clarity and ease of use. Below is an explanation of each field’s purpose with an example for guidance:

Basic Calculator

Input Field

Description

Example Value

Yearly Interest Rate (%)

Enter the annual interest rate on your loan. It helps calculate daily interest and payments.

5.5

Loan Amount/Balance ($)

Provide the current loan balance in dollars, which is used to find the per diem interest payment.

15000

Per Diem Interest (%)

This displays the calculated per diem interest rate based on the yearly rate (1/360 of annual rate).

0.0153

Per Diem Interest Payment ($)

Shows the per diem interest amount in dollars. It depends on the loan amount and daily rate.

2.08

Advanced Calculator

Input Field

Description

Example Value

Yearly Interest Rate (%)

Annual interest rate to see the new per diem interest rate after an extra payment is applied.

5.5

Loan Amount/Balance ($)

Enter the current loan balance before any extra payments to find its impact on daily interest.

15000

Extra Payment ($)

Specify any additional amount you have paid toward the loan to reduce the balance and per diem interest.

500

New Per Diem Interest After Extra Payment ($)

Displays the adjusted per diem interest after applying the extra payment, shown in dollars. This field is readonly.

2.00

Calculation Examples

Below are two examples demonstrating how to use the calculator in each mode. The calculation is broken down step-by-step to show the method.

Basic Calculator Example

Step

Calculation

Result

Yearly Interest Rate (%)

5.5

5.5

Loan Amount ($)

15000

15000

Per Diem Interest (%)

$\frac{5.5}{360} = 0.0153$%

0.0153

Per Diem Interest Payment ($)

$15000 \times \frac{0.0153}{100} = 2.08$

2.08

Advanced Calculator Example

Step

Calculation

Result

Original Loan Amount ($)

15000

15000

Extra Payment ($)

500

500

New Loan Balance After Extra Payment ($)

$15000 – 500 = 14500$

14500

Adjusted Per Diem Interest Payment ($)

$14500 \times \frac{5.5}{360} \div 100 = 2.00$

2.00

To calculate, input the known values, then press Calculate. To start a fresh calculation, press Reset to clear all fields.