Lump Sum Prepayment Calculator

Simulate one-time bonus injections and milestone lump sums to see your exact interest savings and new debt-free date.

Loan & Lump Sum Milestones

$
%
Yrs

๐Ÿ’ฐ Lump Sum Payments

$
Mo #
$
Mo #
$
Mo #
Interest Saved from Lump Sums
$0
You save 0% of original interest!
Time Saved
0 yrs 0 mos
Earlier maturity
New Payoff Date
--
Originally --
Total Lump Sums Injected
$0
Total principal prepayment
Return on Prepayment
+0%
Interest saved / Cash injected
View Full Amortization โ†“

Amortization Schedule

Interactive breakdown of balance, interest, and prepayment impact

PeriodEMI PaidPrincipal PaidExtra PrepaymentInterest PaidTotal PaymentRemaining Balance

Why Lump Sum Prepayments Pack Such a Powerful Punch

When you inject a lump sum into your loan, the lender recalculates the interest on the remaining principal from the very next day.

Rule of Thumb: Every $10,000 lump sum paid in the first 5 years of a 30-year 7% mortgage typically saves over $32,000 to $45,000 in interest charges!

Best Sources for Lump Sum Prepayments

Frequently Asked Questions

What is a lump sum prepayment?

A lump sum prepayment is a single large one-time cash infusion made directly to your loan principal, often originating from an annual work bonus, property sale, investment return, tax refund, or inheritanceโ€”compare recurring monthly injections with our Extra Principal Payment Calculator.

Is it better to prepay a lump sum early in the loan or later?

The earlier in your loan tenure you make a lump sum prepayment, the more interest you will save. Because mortgage interest is calculated daily on the outstanding principal, making a $20,000 prepayment in Year 2 saves more than triple the interest of making the same prepayment in Year 15! Check exact milestone math in our Multi-Lump-Sum Part Prepayment Calculator or Daily Interest Formula Guide.

Can I make multiple lump sum prepayments?

Yes! Most lenders allow you to make multiple part-prepayments whenever you have surplus capital, subject to individual bank termsโ€”always verify ERC limits and charges in our Prepayment Penalty Calculator or Global Bank Presets.

๐Ÿ”ฅ Popular Across Other Categories

Complete 76+ Directory →

Browse Calculation Suites by Category