Extra Payment Calculator
See how extra monthly payments shorten your loan and save interest.
What Is the Extra Payment Calculator?
An extra payment calculator shows what an additional payment each month does to a loan. Beyond the minimum, any extra money goes straight to principal, which shortens the term and cuts the interest you pay. The effect is often bigger than people expect: an extra $100 a month on a 30 year, $200,000 mortgage at 6% pays the loan off almost 5 years early and saves close to $49,000 in interest. This tool takes the loan amount, rate, term, and your extra payment, and returns the new payoff time, the months and years you save, and the interest you avoid.
Key Statistics
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$49,138
Interest saved on a $200,000, 30 year, 6% loan with an extra $100 a month
Source: Amortization calculation
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65%
Share of a typical home loan's payoff that is interest in the early years
Source: Mortgage amortization analysis
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5.4 years
Time cut off a 30 year loan by adding $100 a month to a $200,000 balance at 6%
Source: Amortization calculation
The Formula
Extra payments reduce the outstanding principal directly. With each month, interest is charged on the remaining balance, so a smaller principal from the very first extra payment compounds into large savings over time.
Worked Examples
A $200,000 loan at 6% over 30 years has a $1,199 monthly payment and $231,676 in total interest. Adding $100 to that payment each month pays the loan off in 24.6 years instead of 30, cutting the payoff by 5.4 years and saving $49,138 in interest.
$100 extra on a $200,000 mortgage
- Enter 200000 as the loan amount, 6% interest, 30 year term
- Add an extra $100 monthly payment
- Compare the new payoff time and total interest to the baseline
The loan pays off in about 24.6 years instead of 30, saving roughly $49,138 in interest.
$50 extra on an $18,000 car loan
- Enter 18000 as the loan amount, 7% interest, 5 year term
- Add an extra $50 monthly payment
- See the reduced payoff time and interest saved
A small extra payment shortens the term and lowers the total interest well before the car is paid off.
Real World Use Cases
Paying off a mortgage early
Add a stream of extra payments to a monthly mortgage to clear it years sooner and keep more of your money.
Clearing high interest debt
Apply extra payments to a high rate auto or personal loan to minimize the interest you pay.
Budgeting extra cash
See how a small recurring surplus each month reduces debt instead of vanishing into spending.
Expert Tips
- ✓ Send extra payments explicitly marked for principal to get the full benefit.
- ✓ Even one extra payment at the start of the loan has the largest relative impact.
- ✓ Check for prepayment penalties and weigh them against the interest you would save.
- ✓ Use the same monthly payment for comparison, since the required amount never changes.
Frequently Asked Questions
How does an extra payment reduce interest? ▼
Every extra payment reduces the principal balance before the next interest charge. Since interest is calculated on the smaller balance, the total interest owed drops. The earlier and larger the extra payment, the more interest you avoid.
How much does an extra payment shorten a loan? ▼
It depends on the rate and term. On a 30 year, $200,000 loan at 6%, an extra $100 a month shaves over 5 years off the term. On a shorter or lower rate loan the effect is smaller, so run your own numbers.
Is paying extra every month better than a lump sum? ▼
Both reduce principal and save interest. A consistent monthly extra payment is predictable and compounds steadily, while a lump sum removes a chunk of principal at once. Minimum payments plus consistent extra payments are generally the easiest to maintain.
When should I make an extra payment? ▼
As early as possible. Interest accrues on a declining balance, so the savings are largest when an extra payment lands at the start of the loan. Even one extra payment early can reduce total interest and shorten the term.
Does an extra payment change my required monthly payment? ▼
No. Your required payment stays the same; the extra is applied to principal on top of it. The bonus is that a smaller balance means your loan is cleared sooner and costs less overall.
Are there fees for paying extra on a loan? ▼
Some lenders charge prepayment penalties, while others allow it freely. Check your loan agreement first. Mortgages and student loans typically allow extra payments without penalty, but not all loans do.
Common Mistakes to Avoid
- ⚠ Assuming the extra payment shortens the term but not realizing interest continues to accrue on the remaining balance each month.
- ⚠ Paying extra but not asking the lender to apply it to principal, so it sits as a credit instead of reducing the balance.
- ⚠ Ignoring prepayment penalties that can eat the interest savings on some loans.
- ⚠ Choosing a longer term to lower the monthly payment while missing how much extra interest it adds over time.
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Last updated: · by CalculatorPro Tools