Interest-Only Mortgage Calculator
See the payment during an interest-only mortgage period and how much the payment jumps once amortization begins.
Inputs explained
- Loan Amount — The principal borrowed. Example: 300000.
- Annual Interest Rate — The mortgage's annual rate as a percentage. Example: 6.
- Interest-Only Period — Years during which only interest is paid. Example: 10.
- Total Loan Term — Full length of the mortgage in years. Example: 30.
How to use it
- Fill in the fields above — each input has a hint describing exactly what to enter
- Press Calculate to get your result instantly, right on this page
- Copy the result, save the tool to favorites, or share and embed it anywhere
Understanding the result
Example: A $300,000 loan at 6% with a 10-year interest-only period pays $1,500/month at first, jumping to about $2,149.29 when 20-year amortization begins.
Frequently asked questions
Why does the payment jump so much once the interest-only period ends? During the interest-only period you pay nothing toward principal, so when amortization begins the full loan balance must be paid off in the remaining shorter term, which raises the payment substantially — from $1,500 to about $2,149.29 in the example.
Does the loan balance shrink at all during the interest-only period? No — since only interest is being paid, the principal balance stays exactly the same throughout the interest-only period, unlike a standard amortizing loan where each payment chips away at the balance from day one.
Is the Interest-Only Mortgage Calculator free to use? Yes — it is completely free, with no sign-up, no download and no usage limits. You can use it as often as you need.
Is my data private? Yes. The calculation runs entirely in your browser — the values you enter are never sent to our servers, stored or shared with anyone.
What information do I need? Just the following: Loan Amount, Annual Interest Rate, Interest-Only Period, Total Loan Term. Each field includes a hint explaining exactly what to enter.
Can I use it on my phone? Yes — the tool is fully responsive and works on any device, and the same calculator is available in the EasyWorkCalcs mobile app.
Privacy
Everything you enter into the Interest-Only Mortgage Calculator is processed entirely in your browser. Nothing is uploaded, stored or shared — your data stays on your device.