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Home›Calculators›Mortgage & Real Estate›Mortgage Overpayment Calculator

Mortgage Overpayment Calculator
Interest Saved and Early Payoff Impact

Estimate how recurring or lump sum mortgage overpayments could reduce total interest and shorten your payoff timeline.

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Your Mortgage Overpayment Estimate
Mortgage Setup
€
Current remaining mortgage principal.
%
Annual fixed rate. Zero is allowed.
yrs
Remaining mortgage term used for the standard schedule.
freq
Payment and overpayment timing follow this frequency.
mode
Use auto mode for payment from balance, rate and term, or override manually.
date
Used for payment date labels and payoff timing.
year
Schedule starts from this year.
Recurring Overpayment
extra
Turn on to add an extra amount every payment period.
Lump Sum Overpayment
lump
Turn on to apply one extra payment once.
Interest Saved
—
difference between standard and overpayment scenarios
New payoff date
—
—
Mortgage Balance
—
remaining principal
Standard Payment
—
scheduled payment
Recurring Overpayment
—
per period
Lump Sum Overpayment
—
one-time payment
Standard Total Interest
—
no overpayments
New Total Interest
—
with overpayments
Interest Saved
—
total interest reduction
Standard Payoff Date
—
baseline payoff
New Payoff Date
—
overpayment scenario
Time Saved
—
payoff acceleration
Overpayment Summary
Standard vs Overpayment
Standard payoff date—
Overpayment payoff date—
Total interest difference—
Months saved—
Recurring Only vs Lump Sum Only
Recurring only payoff date—
Lump sum only payoff date—
Interest saved difference—
Total repayment difference—
Lower Rate vs Higher Rate
Lower rate interest saved—
Higher rate interest saved—
Interest saved difference—
Payoff difference—
Model Summary
Standard total repayment—
Revised total repayment—
Final balance—
Overpayment periods used—
Standard Balance vs Overpayment Balance Over Time
Standard balance
Overpayment balance
Milestone Balance Table
YearStandard BalanceOverpayment BalanceInterest Saved So Far
Overpayment Schedule
Showing first 12 payment periods
Payment #DatePaymentPrincipalInterestExtraBalance
Important: This calculator estimates mortgage overpayment impact using a fixed interest rate, fixed payment frequency, and optional recurring or lump sum overpayments. It does not replace lender statements, product rules, overpayment cap rules, penalties, or mortgage advice. It is an estimate only.
✦ Cal, AI Explanation
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Your overpayment estimate is ready. Ask me about interest saved, lump sums, recurring overpayments, or why lender results can differ.

💰 Overpayment Notes

Overpayments reduce principal directly
Earlier overpayments usually save more interest
Lump sums and recurring overpayments affect payoff differently
Fixed-rate model only
Estimate only

Related Calculators

Amortization Schedule Calculator→ Mortgage Payment Calculator→ Mortgage Comparison Calculator→ Loan Repayment Calculator→ Interest-Only vs Repayment→

Related Guides

How Mortgage Overpayments Work→ Recurring vs Lump Sum Overpayments→ Mortgage Interest Saving Guide→

How mortgage overpayments work

Mortgage overpayments reduce principal directly. When the balance falls faster, future interest is charged on a smaller amount, which can lower total interest and shorten the payoff timeline.

Overpayment TypeMain Effect
Recurring overpaymentAdds extra principal reduction each payment period
Lump sum overpaymentApplies one larger balance reduction at a chosen point

Recurring vs lump sum overpayments

Recurring overpayments chip away at the balance steadily, while a lump sum creates one larger reduction at a specific time. Both can save interest, but the impact depends on the amount and how early the overpayment is applied.

Interest saving explained

Interest is calculated on the outstanding balance. That means reducing the balance earlier usually saves more total interest than making the same reduction later in the mortgage timeline.

Early payoff impact explained

Overpayments can shorten the number of periods needed to clear the mortgage. Even moderate extra payments can materially shift the final payoff date when applied over a long fixed-rate term.

Frequently Asked Questions

Do mortgage overpayments really save interest?+
Yes. Overpayments reduce principal directly, which lowers the balance used to calculate future interest.
Is a lump sum better than monthly overpayments?+
It depends on timing and amount. A large early lump sum can be powerful, but steady recurring overpayments can also create substantial savings over time.
Why do early overpayments matter more?+
Because reducing the balance earlier lowers the base on which future interest is charged for more periods.
Can overpayments shorten the term a lot?+
Yes. Depending on the mortgage size, rate, and overpayment amount, the payoff date can move forward materially.
Why can lender results differ from this estimate?+
Lender results can differ because of product rules, overpayment caps, payment timing conventions, fees, penalties, and statement calculation methods outside this simplified model.