Mortgage Offset Account Calculator

A mortgage offset account is a savings account linked to your mortgage that reduces your interest payments. This calculator helps you determine how much you'll save by using an offset account.

What is a Mortgage Offset Account?

A mortgage offset account is a type of savings account that's linked to your mortgage. The money in the account is used to offset the amount of interest you owe on your mortgage each month. This can significantly reduce your monthly payments and the total interest paid over the life of your mortgage.

Offset accounts are different from regular savings accounts because they directly impact your mortgage interest charges. They're particularly useful if you have a variable-rate mortgage, as the savings can be more substantial.

Key Benefits

Lower monthly mortgage payments
Reduced total interest paid over the mortgage term
Potential tax benefits in some countries
No risk of losing principal if the mortgage is repaid early

How Mortgage Offset Accounts Work

When you open a mortgage offset account, the lender agrees to deduct the balance in the account from the amount of interest you owe each month. Here's how it works step by step:

You open a savings account with your mortgage lender
The lender agrees to offset the account balance against your interest charges
You deposit money into the account (either from your own funds or through salary sacrifice)
Each month, the lender deducts the account balance from your interest charges
This reduces your monthly mortgage payment and the total interest paid over the mortgage term

Monthly Interest Calculation:
Monthly Interest = (Remaining Mortgage Balance × Monthly Interest Rate) - Offset Account Balance

Types of Offset Accounts

There are two main types of mortgage offset accounts:

Type	Description	Interest Rate
Standard Offset Account	Interest is paid on the balance in the account	Typically 0.5% to 1% above the base rate
Interest-Free Offset Account	No interest is paid on the balance	0% interest rate

Worked Examples

Let's look at two examples to illustrate how mortgage offset accounts work.

Example 1: Standard Offset Account

Suppose you have a £200,000 mortgage with a 5% annual interest rate. You open a standard offset account with a 1% interest rate and deposit £50,000.

Monthly Interest Without Offset: £833.33
Monthly Interest With Offset: £333.33
Savings Per Month: £500

Example 2: Interest-Free Offset Account

Using the same mortgage, you open an interest-free offset account and deposit £30,000.

Monthly Interest Without Offset: £833.33
Monthly Interest With Offset: £583.33
Savings Per Month: £250

These examples show how even a small offset account can make a significant difference to your monthly payments and the total interest paid over the mortgage term.

Frequently Asked Questions

How much can I save with a mortgage offset account? +

The savings depend on your mortgage balance, interest rate, and the amount you deposit in the offset account. Generally, you can save between £200 and £1,000 per month, depending on these factors.

Are mortgage offset accounts right for everyone? +

Offset accounts are particularly beneficial for people with variable-rate mortgages, as the savings can be more substantial. They may not be as advantageous for those with fixed-rate mortgages or those who don't have significant savings to deposit.

Can I withdraw money from a mortgage offset account? +

Yes, you can withdraw money from a mortgage offset account, but this will reduce the amount that offsets your mortgage interest. Some lenders may charge a fee for withdrawals.

Are there any tax benefits to mortgage offset accounts? +

In some countries, such as the UK, the interest paid on a mortgage offset account may be tax-deductible, which can provide additional savings. However, tax rules can change, so it's important to check with a financial advisor.