Home Loan Repayment Calculator with Offset Account and Extra Repayments

This calculator helps you determine your home loan repayments when you have an offset account and make extra repayments. It shows how these factors affect your interest payments and loan term.

How the Calculator Works

Home loan repayments are calculated based on the principal amount, interest rate, loan term, and any additional factors like offset accounts and extra repayments. An offset account reduces the principal balance by the amount in the account, while extra repayments reduce both the principal and the interest owed.

Key Components

Principal Amount - The initial loan amount
Interest Rate - The annual percentage rate charged
Loan Term - The repayment period in years
Offset Account Balance - The amount in your offset account
Extra Repayments - Additional payments made beyond the minimum

Calculation Process

The calculator first adjusts the principal amount by subtracting the offset account balance. It then calculates the monthly repayment using the standard loan repayment formula, applying the extra repayments to reduce both the principal and interest over time.

Note: This calculator assumes principal-and-interest repayments. Interest-only loans have different calculation requirements.

Formula Used

The calculator uses the following formula to determine the monthly repayment:

Monthly Repayment = P × (r(1+r)^n) / ((1+r)^n - 1)

Where:

P = Adjusted Principal (Principal - Offset Account Balance)
r = Monthly Interest Rate (Annual Rate / 12 / 100)
n = Number of Payments (Loan Term × 12)

Extra repayments are applied each month to reduce the remaining balance, which affects the total interest paid and the loan term.

Worked Example

Let's calculate a home loan with the following details:

Principal Amount	$300,000
Interest Rate	4.5%
Loan Term	30 years
Offset Account Balance	$50,000
Extra Repayments	$200 per month

After adjusting for the offset account, the principal becomes $250,000. The monthly repayment for the remaining balance is calculated as $1,245.50. With the extra $200 payments, the loan will be paid off in approximately 22 years instead of 30, saving $12,000 in interest.

Frequently Asked Questions

How does an offset account affect my loan repayments?: An offset account reduces your loan balance by the amount in the account, which lowers your interest payments. However, the interest continues to accrue on the offset balance.
What happens if I make extra repayments?: Extra repayments reduce both the principal and the interest owed, shortening the loan term and saving on interest costs.
Can I use both an offset account and extra repayments?: Yes, many lenders allow you to use both strategies simultaneously to reduce your loan balance faster.
How accurate is this calculator?: The calculator provides an estimate based on standard loan repayment formulas. For precise figures, consult your lender.