Interest-Only Amortization Schedule

See a month-by-month breakdown of your interest-only loan payments, including the transition from IO to full amortization.

✓ Month-by-month payment detail

✓ IO period vs. amortizing period

✓ Running balance shown

Interest-only note calculator

Calculate IO payments and balloon balance at maturity.

$
%
Monthly IO payment
$1,562.50
Balloon due at maturity: $250,000.00
Total interest over term: $93,750.00
Total paid (interest + balloon): $343,750.00
Annual interest
$18,750.00
Total payments
60

How an IO Amortization Schedule Works

An interest-only loan amortization schedule has two distinct phases:

Phase 1: Interest-Only Period

MonthPaymentInterestPrincipalBalance
1$1,750$1,750$0$300,000
2$1,750$1,750$0$300,000
...$1,750$1,750$0$300,000
60$1,750$1,750$0$300,000

Example: $300,000 at 7% with 5-year IO period

Phase 2: Amortizing Period

After the IO period, the remaining balance is amortized over the remaining term (e.g., 25 years on a 30-year mortgage). Payments jump because they now include principal. In this example, the payment would increase from $1,750 to approximately $2,120/month.

Key Insight

The longer the IO period, the higher the amortizing payments afterward—because you have less time to repay the same principal. A 10-year IO on a 30-year loan means you're amortizing over just 20 years instead of 30.

Frequently Asked Questions

What does an interest-only amortization schedule look like?\u25BE
During the IO period, payments are flat (just interest) and the balance stays constant. After the IO period, payments increase as principal amortization begins.
How is interest calculated during the IO period?\u25BE
Monthly interest = (Outstanding Balance × Annual Rate) ÷ 12. The balance and payment remain constant throughout the IO period.