This calculator estimates the monthly payment and total interest on a fixed-rate personal loan from its amount, APR, and term. Enter the proposed loan’s figures to compare its scheduled cost with your existing loan; refinancing timing also depends on fees, payoff balance, and how long you expect to keep the debt.
Formula
The calculator uses the standard fixed-payment loan formula. Let p be the amount financed in dollars, apr the annual percentage rate in percent, r the monthly rate, and n the number of monthly payments. It calculates:
- Monthly rate: r = apr / 1200.
- Number of payments: n = yrs × 12, where yrs is the term in years.
- Monthly payment: pmt = p × r / [1 − (1 + r)−n], rounded to cents.
- Total interest: int = pmt × n − p, using the rounded monthly payment.
These figures model a new loan’s scheduled payments. For a real refinance comparison, enter the amount that would actually be borrowed to pay off the current loan, including any financed charges, and compare results against the current loan’s remaining payments and payoff amount.
Worked Example
Using the calculator’s default inputs—$20,000, 8% APR, and five years:
- Monthly rate: 8 / 1200 = 0.0066667.
- Number of payments: 5 × 12 = 60.
- Payment: $20,000 × 0.0066667 / [1 − (1.0066667)−60] = $405.53 per month, rounded to cents.
- Total paid using that rounded payment: $405.53 × 60 = $24,331.80.
- Total interest: $24,331.80 − $20,000 = $4,331.80.
Assumptions
- The interest rate is fixed for the full term.
- Payments are equal, made monthly, with the first payment one month after borrowing.
- Interest compounds monthly at APR / 12.
- The estimate excludes lender fees, taxes, insurance, and any other charges; it also does not model payment dates, late payments, or a changing balance from extra payments.
When Refinancing May Be Worth Comparing
There is no universal calendar date that makes refinancing appropriate. Compare offers when you can obtain actual terms and have a current payoff figure, especially if your loan circumstances have changed or you want to evaluate a different payment schedule. The useful question is not simply whether a new APR looks lower: it is whether the complete new-loan cost and timeline compare favorably with keeping the existing loan.
A longer term can reduce the required monthly payment while increasing the number of months interest accrues. A shorter term can raise the monthly payment even if the total interest estimate falls. Compare both monthly cash flow and total remaining cost, rather than treating either number as the whole answer.
How to Compare a Refinance in Dallas
Dallas does not change the calculator’s arithmetic. However, loan offers and fees vary by lender and applicant, so use the written disclosures for the specific transaction rather than assuming a rate or charge. Gather the same information for each offer, and check whether quoted costs are paid upfront or added to the new balance.
- Request the existing loan’s current payoff amount and remaining payment schedule. A payoff figure can differ from the balance shown on a recent statement because interest accrues and the figure is date-specific.
- Collect each proposed loan’s amount, APR, term, monthly payment, and itemized charges. Ask whether the APR includes the charges and whether any fee is financed.
- Use the calculator for the proposed amount, rate, and term. If costs are rolled into the loan, include them in the amount financed; if paid separately, track them separately in your comparison.
- Compare the new loan’s total scheduled payments plus upfront costs with the remaining payments on the existing loan. Account for any payment already due or other payoff requirements shown in the lender’s documents.
- Check the break-even period when there are upfront costs: divide those costs by the monthly payment reduction only if the new payment is lower. This is a rough cash-flow measure, not a full cost comparison; it does not capture a longer term or differing total interest.
For example, if a refinance has $600 in upfront costs and lowers the monthly payment by $50, the simple break-even calculation is $600 / $50 = 12 months. That does not establish a net saving: a longer repayment period may leave more total payments, and paying the loan off or changing plans before that point changes the comparison.
Costs, Timing, and Common Misconceptions
A lower monthly payment alone does not prove that refinancing reduces the overall cost. It may result from extending repayment, adding fees to the balance, or both. Likewise, comparing advertised rates without the loan amount, APR, term, and fees leaves out information needed to compare the actual payment schedule.
Ask for the payoff amount’s effective date and whether the new lender pays the old loan directly. Check the new agreement for origination or other charges, prepayment terms, and whether the stated payment assumes automatic or on-time payments. Do not assume an old loan’s remaining balance is identical to the amount required to close it.
The calculator is an estimate, not a refinance break-even calculator. It assumes a fixed rate and regular payments, and it cannot account for an existing loan’s exact amortization, date-specific payoff, fees, or your expected payoff date. For a precise comparison, use the documents’ cash flows and verify figures with the lenders.
Frequently Asked Questions
When should I refinance a personal loan?
Consider comparing terms when you have current payoff information and written offers that can be evaluated side by side. There is no fixed waiting period or date that applies to every borrower.
Does refinancing always lower the total interest?
No. A lower payment or APR does not guarantee lower total interest. A longer term, financed fees, or a different payoff schedule can change the total amount paid.
How do I work out a refinance break-even point?
For a basic estimate, divide upfront costs by the monthly payment reduction, if there is one. Then separately compare total remaining payments, because the simple calculation does not account for a changed term or total interest.
Should I include fees in the new loan amount?
If the lender adds fees to the balance, include them in the amount financed. If you pay them upfront, keep them separate and add them to the refinance’s cost comparison.
Does living in Dallas change the payment formula?
No. The fixed-payment formula is the same; the figures that vary are the specific loan terms and charges offered for the transaction. Get those figures directly from the lender.
The result is an estimate, and the lender’s disclosure gives the exact figures.
Related
Formula used
in p | Loan amount | $ | 20000 | 1 | 100000000 in apr | Interest rate (APR) | % | 8 | 0.01 | 100 in yrs | Loan term | years | 5 | 0.0833 | 50 out pmt | Monthly payment | $ | p * (apr / 1200) / (1 - (1 + apr / 1200) ^ -(yrs * 12)) | 2 out int | Total interest | $ | pmt * yrs * 12 - p | 2
Each line is one input (in, sel, list) or one result (out: label, unit, formula, decimals). How the calculators work
Method: the standard loan formula for this calculation, fixed rate and monthly compounding unless stated, rounded as each result states. Not financial advice; no lender, rate or product is recommended. See formulas and assumptions, the disclaimer or report an error.
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