Mortgage Amortization Simulator
Mortgage Paydown Simulator
Compare original amortization vs. a lump sum + extra monthly payments.
Loan Amount ($)
Interest Rate (% / year)
Term (years)
Start Month (0 = now)
One-Time Extra Payment ($)
Lump Sum Applied at Month #
Extra Monthly Payment ($)
Max Months to Show
Note: “Month #” is counted from loan start. For example, 0 = first payment, 12 ≈ after 1 year of payments.
▶ Run Simulation
Original Monthly Payment
$0
Original Payoff (months)
0
New Payoff (months)
0
Months Saved
0
Total Interest - Original
$0
Total Interest - New
$0
Interest Saved
$0