calculate-loan

01 Loan payments

Personal Loan APR Calculator and Monthly Cost

Calculator No. 01-3862 · Updated · Formula and assumptions shown below

Monthly payment $405.53
Total interest
$4,331.80
= Monthly payment × loan term × 12 − loan amount
Loan amount
$20,000
Input
Interest rate (APR)
8 %
Input
You enter
Loan amount ($), Interest rate (APR) (%), Loan term (years)
You get
Monthly payment ($), Total interest ($)
Rounding
2 dp

Estimate for education, not financial advice. The result follows from the numbers you enter and the formula shown. It is not a quote or an offer, and it does not include fees, taxes or insurance unless the calculator asks for them. Ask your lender for the exact figures.

This personal loan APR calculator estimates the monthly payment and total interest for a fixed-rate loan. Enter the amount borrowed, APR, and term to see the scheduled payment and interest under the assumptions below.

Formula

The calculator uses the standard fixed-payment loan formula. It converts the annual percentage rate to a monthly rate, calculates the payment that amortizes the principal over the selected number of months, rounds that payment to the nearest cent, then estimates total interest from the rounded payments.

  • p is the amount borrowed, in dollars.
  • apr is the annual percentage rate, entered as a percentage per year.
  • r is the monthly rate as a decimal: apr ÷ 1,200.
  • n is the number of monthly payments: years × 12.
  • pmt is the monthly payment, in dollars.
  • int is estimated total interest, in dollars.

Before rounding, the payment formula is pmt = p × r ÷ [1 − (1 + r)−n]. Here, r = apr ÷ 1,200 and n = years × 12. The total-interest calculation is int = pmt × n − p. APR is entered as a percentage, so an APR of 8% becomes 0.08 per year and 0.08 ÷ 12 per month.

Worked Example

Using the calculator’s default inputs—$20,000 borrowed, 8% APR, and five years:

  1. Convert the APR to a monthly decimal rate: 8 ÷ 1,200 = 0.0066667.
  2. Convert the term to payments: 5 × 12 = 60 months.
  3. Substitute into the payment formula: $20,000 × 0.0066667 ÷ [1 − (1.0066667)−60] = about $405.53 per month after rounding.
  4. Calculate interest using the rounded payment: $405.53 × 60 − $20,000 = $4,331.80.

The calculator therefore displays a monthly payment of $405.53 and estimated total interest of $4,331.80. A lender’s actual schedule can differ because of payment dates, rounding conventions, fees, or other loan terms.

Assumptions

  • The interest rate is fixed for the full term.
  • Payments are equal monthly installments, made at the end of each monthly period.
  • Interest accrues monthly using APR ÷ 12.
  • The estimate excludes origination or other fees, taxes, insurance, and any optional products. It assumes no late payments, extra payments, or changes to the loan.

What Personal Loan APR Means

APR is an annualized measure of the cost of borrowing, expressed as a percentage. It can reflect the interest rate and certain borrowing charges, depending on the loan and the lender’s disclosures. It is useful when reviewing the cost of credit, but the number alone does not tell you the exact monthly payment: the amount borrowed, repayment term, payment schedule, and included charges also matter.

APR and the interest rate are related but not always identical. The interest rate is the rate used to calculate interest on the unpaid balance. APR is intended to express borrowing cost on an annual basis and may account for certain fees. The calculator treats the entered APR as the rate used for monthly amortization. If a lender’s APR includes fees that are charged separately or financed into the balance, this simplified model will not reproduce every disclosure figure.

How to Use and Interpret the Estimate

Enter figures from the loan offer or disclosure rather than guessing. If the lender provides a monthly payment, compare it with the calculator output only after checking that the principal, APR, term, and fee treatment match. A longer term spreads repayment across more months and can reduce the scheduled monthly amount, while leaving the balance outstanding for longer; total interest depends on the rate, amount, and payment schedule together.

The total-interest output is the estimated sum of the rounded monthly payments minus the starting principal. It is not the total amount paid: to estimate that, multiply the displayed monthly payment by the number of months. In the example, total payments are $405.53 × 60 = $24,331.80, of which $20,000 repays principal and $4,331.80 is estimated interest.

Use the calculator to understand how inputs affect a standard amortizing loan, not to determine whether an offer is suitable or whether someone will qualify. To establish the actual payment and total cost, check the lender’s personalized disclosure, which should show applicable charges and payment terms.

Common Limits and Mistakes

  • Entering 8 instead of 0.08: Enter APR as a percent, such as 8 for 8%, not as a decimal fraction.
  • Mixing years and months: The term field is in years; the formula converts years to months by multiplying by 12.
  • Treating APR as the full offer: The calculator has no input for fees, so it cannot model fee financing, deductions from proceeds, or lender-specific calculations.
  • Assuming every payment is identical in practice: Due dates, daily interest calculations, payment adjustments, or a final payment correction can change the schedule.
  • Ignoring early or late payments: Extra payments may change payoff timing and interest; late payments can create additional costs. Neither is included.

Results are rounded to cents. Small differences from an offer can arise from rounding each installment, the timing of the first payment, or the lender’s exact calculation method. This model is for a conventional fixed-rate installment loan with regular monthly payments; it does not calculate variable-rate changes or irregular payment schedules.

Frequently Asked Questions

Is APR the same as the personal loan interest rate?
No. The interest rate is used to calculate interest on the balance. APR is an annualized cost measure that may include certain fees. What is included depends on the loan disclosure.

Does a lower APR always mean a lower monthly payment?
Not by itself. Payment also depends on the amount borrowed and repayment term, and fee treatment can affect comparisons. Compare offers using the same principal, term, and disclosed costs.

Why is my lender’s payment different from this calculator?
The lender may use different fee treatment, payment dates, rounding, or interest-accrual conventions. Confirm that the APR, amount financed, term, and schedule entered here match the offer.

Does this calculator include loan fees?
No. There is no fee input. It estimates payments using the entered principal and APR, so it cannot calculate fees paid upfront or added to the balance.

Can I use the result to know whether I will be approved?
No. This is arithmetic only. It does not assess applications, approval criteria, or individual circumstances.

This result is an estimate; 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 | $ | round(p * (apr / 1200) / (1 - (1 + apr / 1200) ^ -(yrs * 12)), 2) | 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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