Amortization Calculator: See How Your Mortgage Payments Break Down (2026)
By Wealthvieu · Updated
An amortization schedule shows exactly how every dollar of your mortgage payment is allocated between principal and interest over time. Here’s how it works and how to pay less interest.
Table of Contents
How Amortization Works
In the early years, most of your payment goes to interest. Over time, the interest portion shrinks and the principal portion grows:
$300,000 Loan, 6.5% Rate, 30-Year Term
Payment #
Monthly Payment
Principal
Interest
Remaining Balance
1 (Month 1)
$1,896
$271
$1,625
$299,729
12 (Year 1)
$1,896
$286
$1,610
$296,623
60 (Year 5)
$1,896
$372
$1,524
$281,134
120 (Year 10)
$1,896
$514
$1,382
$255,093
180 (Year 15)
$1,896
$709
$1,187
$218,510
240 (Year 20)
$1,896
$979
$917
$168,084
300 (Year 25)
$1,896
$1,352
$544
$99,073
360 (Year 30)
$1,896
$1,886
$10
$0
How Interest Piles Up
Total Interest Paid by Loan Term ($300,000 Loan)
Loan Term
Rate
Monthly Payment
Total Interest
Total Cost
Interest as % of Loan
15 years
5.75%
$2,491
$148,478
$448,478
49%
20 years
6.00%
$2,149
$215,797
$515,797
72%
25 years
6.25%
$1,987
$296,002
$596,002
99%
30 years
6.50%
$1,896
$382,633
$682,633
128%
A 30-year mortgage at 6.5% costs you $382,633 in interest—more than the original loan amount.
Principal vs. Interest Over Time
$300,000 Loan at 6.5%, 30-Year Term
Year
Annual Interest Paid
Annual Principal Paid
% Going to Interest
Remaining Balance
1
$19,410
$3,342
85%
$296,658
5
$18,336
$4,416
81%
$281,134
10
$16,693
$6,059
73%
$255,093
15
$14,411
$8,341
63%
$218,510
20
$11,234
$11,518
49%
$168,084
25
$6,730
$16,022
30%
$99,073
30
$532
$22,220
2%
$0
15-Year vs. 30-Year Amortization
Feature
15-Year Mortgage
30-Year Mortgage
Monthly payment ($300K, ~6%)
$2,491
$1,896
Payment difference
+$595/month
—
Total interest paid
$148,478
$382,633
Interest savings
$234,155
—
Equity at year 5
$100,000+
$19,000
Equity at year 10
$220,000+
$45,000
Rate
Usually 0.5-0.75% lower
Higher
Who Should Choose 15 Years
Choose 15-Year If
Choose 30-Year If
You can comfortably afford the higher payment
You need the lower monthly payment
You want to be debt-free faster
You want flexibility in your budget
You’re closer to retirement
You’d invest the payment difference
You want to build equity rapidly
You’re buying your first home
Impact of Extra Payments
$300,000 Loan, 6.5%, 30-Year Term ($1,896/month)
Extra Payment Strategy
New Payoff Time
Years Saved
Interest Saved
No extra payments
30 years
—
—
$100/month extra
25 years, 2 months
4 years, 10 months
$72,478
$200/month extra
22 years
8 years
$121,543
$300/month extra
19 years, 8 months
10 years, 4 months
$157,234
$500/month extra
16 years, 10 months
13 years, 2 months
$204,892
1 extra payment per year
25 years, 8 months
4 years, 4 months
$64,267
Biweekly payments
25 years
5 years
$70,835
Just $200/month extra saves over $121,000 in interest and pays off your mortgage 8 years early.
Where Extra Payments Go
Regular Payment
Extra $200 Payment
Total
$271 to principal
$200 to principal
$471 to principal
$1,625 to interest
$0 to interest
$1,625 to interest
Extra payments go entirely to principal, which reduces your balance faster and decreases future interest charges.
Amortization by Interest Rate
$300,000 Loan, 30-Year Term
Rate
Monthly Payment
Total Interest
Interest as % of Loan
4.0%
$1,432
$215,609
72%
5.0%
$1,610
$279,767
93%
5.5%
$1,703
$313,212
104%
6.0%
$1,799
$347,515
116%
6.5%
$1,896
$382,633
128%
7.0%
$1,996
$418,527
140%
7.5%
$2,098
$455,157
152%
8.0%
$2,201
$492,480
164%
Each 0.5% increase in rate costs about $35,000-$37,000 more in total interest on a $300,000 loan.
Building Equity Through Amortization
When You Reach Key Equity Milestones ($300,000 Loan at 6.5%)
Equity Goal
No Extra Payments
$200/Month Extra
10% equity ($30,000)
Year 7
Year 4
20% equity ($60,000)*
Year 12
Year 7
30% equity ($90,000)
Year 16
Year 10
50% equity ($150,000)
Year 21
Year 14
100% equity (paid off)
Year 30
Year 22
*20% equity = can drop PMI on conventional loans.
Biweekly Payment Strategy
Instead of 12 monthly payments, make 26 half-payments (every 2 weeks):
Feature
Monthly Payments
Biweekly Payments
Payment frequency
12 per year
26 half-payments (= 13 full payments)
Effect
12 payments
Equivalent of 13 payments
Extra payment per year
0
1 full extra payment
Payoff time ($300K, 6.5%)
30 years
25 years
Interest saved
—
$70,835
Biweekly payments are the easiest extra payment strategy because they align with most people’s pay schedules and don’t feel like a sacrifice.
