Accounting Loan Interest Calculator

Calculate accounting loan interest with our free calculator. Compute monthly payments, total interest, and amortization schedule for loans and mortgages.

How to Use This Calculator

This accounting loan interest calculator helps you determine the monthly payments, total interest paid, and amortization schedule for a loan. Simply enter the loan amount, interest rate, and loan term, then click "Calculate" to see the results.

Key Features

Calculate monthly loan payments
Determine total interest paid over the loan term
View amortization schedule
Visualize interest vs. principal payments

Input Requirements

You'll need to provide:

Loan amount (principal)
Annual interest rate
Loan term in years

Output Results

The calculator will display:

Monthly payment amount
Total interest paid
Total amount paid (principal + interest)
Amortization schedule showing each payment's principal and interest components
A chart visualizing the interest vs. principal breakdown

Formula Used

The calculator uses the standard loan payment formula:

M = P [ i(1 + i)ⁿ ] / [ (1 + i)ⁿ - 1 ]

Where:

M = monthly payment
P = principal loan amount
i = monthly interest rate (annual rate divided by 12)
n = number of payments (loan term in years × 12)

Total interest paid is calculated as:

Total Interest = (M × n) - P

Total amount paid is simply the sum of the monthly payments:

Total Amount Paid = M × n

Worked Example

Let's calculate a $200,000 loan at 4.5% annual interest for 30 years.

Step 1: Convert inputs

Principal (P) = $200,000
Annual interest rate = 4.5% = 0.045
Monthly interest rate (i) = 0.045 / 12 ≈ 0.0037917
Loan term in months (n) = 30 × 12 = 360

Step 2: Calculate monthly payment

M = 200,000 [ 0.0037917(1 + 0.0037917)³⁶⁰ ] / [ (1 + 0.0037917)³⁶⁰ - 1 ]

Calculating this gives M ≈ $1,073.64

Step 3: Calculate total interest

Total Interest = (1,073.64 × 360) - 200,000 ≈ $116,694.40

Step 4: Calculate total amount paid

Total Amount Paid = 1,073.64 × 360 ≈ $386,510.40

So for this $200,000 loan, you would pay approximately $1,073.64 per month, totaling $386,510.40 over 30 years, with $116,694.40 going to interest.

Frequently Asked Questions

What is the difference between simple and compound interest?: Simple interest is calculated only on the original principal amount, while compound interest is calculated on both the initial principal and the accumulated interest from previous periods. This calculator uses compound interest calculations.
How does loan term affect monthly payments?: A longer loan term means lower monthly payments but higher total interest paid. A shorter term results in higher monthly payments but lower total interest. The calculator shows both scenarios.
What is the amortization schedule?: The amortization schedule shows how each monthly payment is divided between principal repayment and interest payment. This helps you understand how quickly you're paying down the loan.
Can I use this calculator for mortgages?: Yes, this calculator works for any type of loan, including mortgages. Just enter the mortgage amount, interest rate, and term to calculate payments.
How accurate are the calculations?: The calculator uses standard accounting formulas and provides precise calculations based on the inputs you provide. For exact figures, consult with a financial advisor.