Repayment Calculator
Solve your loan repayment two ways: enter the loan term to find the required monthly payment, or enter the monthly payment you can make to find how long repayment takes. Add extra monthly payments to see exactly how many months and dollars you save on any fixed-rate loan.
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How It Works
Enter the loan amount, interest rate, and desired term in months. The calculator computes the equal monthly payment that fully amortizes the loan over that term. Add extra payments to see accelerated payoff.
M = P × r(1+r)^n / [(1+r)^n - 1]$20,000 at 6.5% for 60 months = $391.32/moEnter the loan amount, interest rate, and the monthly payment amount you can make. The calculator determines exactly how many months it takes to pay off the loan at that payment level.
n = -ln(1 - Pr/M) / ln(1+r)$20K at 6.5% paying $450/mo = 52 monthsExtra payments reduce the principal immediately. The simulation replays every remaining payment with the extra applied and calculates the new payoff date and total interest, showing exact savings versus the base scenario.
New months = simulation with (standard + extra) payment per month+$100/mo on $20K at 6.5%: 47mo vs 60mo, saves $780The minimum viable payment must exceed the monthly interest charge. Below this threshold, the balance grows. The calculator warns if the entered payment is below the interest charge and shows the minimum required.
Minimum = Loan × (Rate/12)$20K at 6.5%: minimum = $20K × 0.542% = $108.33/moFor any loan, the total cost equals the monthly payment times the number of months. Higher payments mean more months saved and less total interest. The calculator shows total paid and total interest for easy comparison.
Total = Monthly × Months; Interest = Total - Principal$391/mo × 60 = $23,479 total, $3,479 interestPaying half the monthly amount every two weeks results in 26 half-payments or 13 full monthly payments per year. This one extra payment per year reduces a 5-year loan by several months with no change in budget discipline.
Bi-weekly = Monthly / 2, paid 26 times per year = 13 full payments$391 monthly → $195.50 bi-weekly = 1 extra payment/yearQuick Reference
Common examples — verify instantly above.
$10K, 8%, 36mo
Monthly payment
$313.36/mo
$20K, 6.5%, 60mo
Monthly payment
$391.32/mo
$25K, 10%, 48mo
Monthly payment
$633.44/mo
$20K at 6.5%, $450/mo
Months to pay off
52 months
$15K at 12%, $400/mo
Months to pay off
46 months
+$100/mo extra
$20K at 6.5%, 60mo term
47 months, $780 saved
Minimum payment
$20K at 6.5%
Must exceed $108.33/mo
Bi-weekly benefit
$391/mo → $195.50 bi-weekly
56 months vs 60 months
Tips & Shortcuts
Use Fixed Payment mode before borrowing to verify your intended payment actually covers more than interest alone and pays off the loan in a reasonable timeframe.
Even rounding up to the next $50 increment over the required minimum creates meaningful savings over the loan term without significantly impacting the budget.
Apply any unexpected windfalls — tax refunds, bonuses, gifts — directly to principal as a one-time extra payment. Every dollar applied early saves more than a dollar applied later.
The fixed payment mode is useful for credit card planning: enter your balance, rate, and current payment to see exactly how long payoff takes under the minimum payment strategy.
For multiple loans, compare the extra payment impact across all loans. The same $100 extra saves more on the loan with the highest interest rate.
Set up automatic payments for consistency. Missing even one payment resets your momentum and may trigger a late fee or rate increase.
Common Mistakes to Avoid
Making only the minimum required payment without checking total cost
Minimum payments are designed to keep you in debt longer and maximize interest revenue for the lender. Calculate the total cost of minimum-only payments and consider increasing the amount.
Not checking the minimum interest coverage before choosing a payment amount
A payment below the monthly interest charge means your loan balance grows. If your payment is too small to cover interest, the loan never pays off — a dangerous situation called negative amortization.
Treating all extra payments equally regardless of timing
Extra payments applied earlier in the loan life save more total interest than the same extra payments applied later. Front-loading extra payments maximizes savings.
Confusing fixed-payment with minimum payment
Your fixed monthly payment in this calculator is the amount you commit to paying, not the minimum allowed. Always paying exactly the calculated minimum leaves no margin for interest fluctuations.
Not verifying whether the loan allows prepayment
Some personal and auto loans have prepayment penalties. Confirm there is no penalty clause before applying extra payments. Even small penalties can offset the interest savings from early payoff.
Using bi-weekly payment math without confirming lender acceptance
Not all lenders accept bi-weekly payments directly. Some require monthly payments and hold extra funds until the next cycle. Verify your lender applies bi-weekly payments immediately to principal.
Frequently Asked Questions
Fixed-term repayment calculates the monthly payment needed to fully pay off a loan in a set number of months. Fixed-payment repayment works in reverse — you enter the monthly amount you can pay and the calculator determines how many months until the loan is paid off.
Extra payments go directly to principal, reducing the balance faster. This means less interest accrues each month, and a greater portion of each regular payment goes to principal. The compounding effect is significant — an extra $100 per month on a $15,000 loan at 12% cuts 8 months off repayment and saves $700 in interest.
This calculator works for any fixed-rate amortized loan: personal loans, auto loans, student loans, business loans, mortgages, and boat loans. It does not apply to revolving credit (credit cards), variable-rate loans, or interest-only loans.
If the monthly payment is less than the monthly interest charge, the loan balance grows instead of shrinking — this is called negative amortization. The calculator detects this and displays an error. Your payment must at least cover the monthly interest to make progress.
Bi-weekly payments (half the monthly amount every two weeks) result in 13 full payments per year instead of 12. This one extra payment per year can cut years off a 30-year mortgage. For shorter loans, the effect is smaller but still beneficial.
The fastest approach is combining the fixed minimum payment with as much extra principal payment as possible, applied consistently every month. Applying windfalls (tax refunds, bonuses) directly to principal provides additional acceleration. Any prepayment strategy without penalty beats waiting.
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