How do i calculate daily interest on a loan

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How to Calculate Daily Interest

Now, if you're like me, and need to know what's going on "under the hood", here is how I set up the calculator to calculate daily interest.

How To Calculate Daily Interest

To illustrate how to calculate daily interest, I'll use the following example:

  • Original principal: $10,000
  • Annual Interest Rate: 10%
  • Number of days: 90
Simple Daily Interest

To calculate the daily simple interest on a $10,000, 10% note for 90 days (please allow for rounding differences):

  1. Convert the percentage rate to a decimal: 10 ÷ 100 = 0.10
  2. Convert the annual rate to a daily rate: 0.10 ÷ 365 = 0.00027397
  3. Multiply the daily rate by the principal: 10000 × 0.00027397 = $2.74
  4. Multiply the daily interest by the number of days: $2.74 × 90 = $246.60

Since we're calculating simple interest, the $246.60 is not added to the principle for any subsequent periods.

Compounding Daily Interest

To calculate the daily compounding interest on a $10,000, 10% note for 90 days (please allow for rounding differences):

  1. Convert the percentage rate to a decimal: 10 ÷ 100 = 0.10
  2. Convert the annual rate to a daily rate: 0.10 ÷ 365 = 0.00027397
  3. Add 1 to the daily rate: 1 + 0.00027397 = 1.00027397
  4. Raise the daily rate factor to the number of days: 1.0002739790 = 1.0249538
  5. Subtract 1 from the raised factor: 1.0249538 - 1 = 0.0249538
  6. Multiply the principal by the 90-day rate factor: 10000 × 0.0249538 = $249.54

Since we're calculating compound interest, the $249.54 is added to the principal for the next compounding period.

If you find home loan interest calculations mysterious, you’ll be pleased to know they’re actually pretty straightforward. Best of all, calculating how much interest you’re paying at any given time is a walk in the park.

How interest charges are calculated

Your total home loan interest costs will depend on a number of factors, including:

  • the amount you’ve borrowed
  • your interest rates over time
  • the term of the loan
  • your repayments
  • any offset accounts

In most cases interest is calculated daily and is based on the outstanding balance of your loan. This doesn’t include any money you may have in a linked offset account if you have one included with your home loan package.

If you want to get an idea of how much your interest charge is on a particular day, all you have to do is multiply the remainder of your outstanding loan balance (minus any offset funds) by your annual interest rate then divide it by 365.

How to work out interest on your home loan

You might be surprised at just how easy working out interest costs can be.

If your hypothetical loan balance of $460,000 carried a standard variable interest rate of 2.29% per annum and you didn’t have an offset account, calculating your daily interest charge is as simple as this:   

$460,000 x 0.0229 / 365 = $28.86 interest per day

If your repayments are monthly and you didn’t touch your loan during the month (such as by redrawing, for example), working out your monthly interest charge is simple. You just need to multiply your daily interest charge from above by the number days in the month. In the case of January, it’d look like this:

$28.86 x 31 = $894.69 interest for January

Of course, your standard variable interest rate is subject to change at any time, so the amount of interest charged on your loan could change during the month. Your actual repayment amounts will also be different to the amount of interest charged. They’ll include things like principal, interest and fees and are calculated according to factors unique to your loan.

But despite only taking a few seconds, working out your interest costs can shed light on your loan in surprising ways.

Why calculating interest charges yourself can be handy

Knowing how interest is calculated can equip you with valuable knowledge about your loan.

For example, you might recognise that more frequent repayments can help you save. This is because weekly or fortnightly repayments reduce the amount outstanding on your loan more frequently than monthly repayments.

It’s also beneficial to know how interest is paid over the life of your loan. When you first start making repayments, you might pay more interest than you expect. It’s helpful to know that the more you pay off your mortgage principal (that is, the amount you owe the bank), the less interest you pay if your rate remains the same.

Using home loan calculators to work out interest charges

If you’re looking for an even simpler way to calculate interest charges, home loan calculators are the way to go. Suncorp Bank’s calculators can help you work out interest charges whether you’re:

  • buying your first home
  • buying your next home
  • investing in a property
  • switching to Suncorp Bank from another lender

Calculators can be a great way to find out a wide variety of loan-related information. You can find out:

  • How much you could potentially borrow
  • What your mortgage repayments might be
  • How much you could potentially save by making extra loan repayments

These are just the tip of the iceberg, though. Make sure to check out our other calculators to find other ways you could potentially save.

The home loan interest rates you need to know

Home loans are usually offered with either variable or fixed interest rate options. In both cases interest is usually still calculated on a daily basis.

  • Variable rates can change depending on the bank’s lending costs and other factors. In Australia, rate fluctuations often relate to changes in the interest rate targets set by the Reserve Bank of Australia.
  • Fixed rates remain constant for an agreed time period at the start of your loan term (typically between one and five years). If you choose a fixed rate home loan, it’ll automatically switch to a variable rate after the fixed rate period.

Understanding how different types of home loans work, and understanding their features and options, can help you choose which is likely to work best for you.

Get a better understanding of interest rates

To learn more about Suncorp Bank’s home loan interest rates, we’re happy to lend a helping hand. Our home lending experts can help you understand your options and all consultations are 100% obligation-free.

Talk to a home lending specialist

Read more:

  • Home loan offset account: how to make it work for you
  • How to get a home loan
  • Fixed vs variable loan: What's the difference?

Information is intended to be of a general nature only and any advice has been prepared without taking into account any person's particular objectives, financial situation or needs. We do not accept any legal responsibility for any loss incurred as a result of reliance upon it – please make your own enquiries. Home Loans are provided by Suncorp-Metway Ltd ABN 66 010 831 722 AFSL No. 229882 Australian Credit Licence 229882 (“Suncorp Bank”) to approved applicants only. Fees, charges, terms and conditions apply and are available on request.

How do you figure daily interest rate?

How do I calculate my daily periodic rate?.
Confirm the current APR rate on your credit card: Look at your monthly statements to find your current Annual Percentage Rate..
Divide this percentage by 365: Once you have found the APR, divide it by 365 (the number of days in a year) to find out your daily periodic rate..

What is daily interest rate on a loan?

The daily interest is equal to the annual rate and then divided by 365 (or 366 during a leap year). Example: If you have a balance of $10,000 at a 3% interest rate, the daily interest would be about $0.82.

How do you calculate simple interest in one day?

Simple Interest = P × n × r / 100 × 1/365 Here 'P' is the principal amount, 'n' is the number of days, and 'r' is the rate of interest per annum. The formula of simple interest is divided by 365 to obtain the rate of interest for one day.

What does it mean if interest is calculated daily?

Daily compounded interest means interest is accumulated daily and is calculated by charging interest on principal plus interest earned daily; therefore, it is higher than interest compounded on a monthly/quarterly basis due to the high frequency of compounding.