3-Year Personal Loan Repayment Schedule Calculator

This calculator estimates the monthly payment and total interest for a fixed-rate personal loan repaid over three years, then shows how each payment reduces the balance. Enter the loan amount and APR to see the scheduled figures; the schedule assumes 36 equal monthly payments.

Formula

The fixed monthly payment is calculated using the standard amortizing-loan formula: M = round(P × r ÷ [1 − (1 + r)⁻ⁿ], 2). Here, M is the monthly payment in dollars, P is the amount borrowed in dollars, r is the monthly interest rate as a decimal (APR ÷ 1,200), and n is the number of monthly payments (term in years × 12). Rounding the payment to cents before calculating the totals reflects a regular payment amount; actual lender calculations may differ.

Total of payments is T = M × n, in dollars. Estimated total interest is I = T − P, in dollars. The calculator’s first result is the monthly payment, followed by total interest and the total scheduled payments. With the three-year default, n is 36.

Worked Example

Using the calculator’s default inputs, the principal is $20,000, APR is 8%, and the term is 3 years. Convert the APR to a monthly decimal rate: r = 8 ÷ 1,200 = 0.0066667. The number of payments is n = 3 × 12 = 36.

Substitute those values into the payment formula: M = round(20,000 × 0.0066667 ÷ [1 − (1.0066667)⁻³⁶], 2) = $626.74 per month. The total of the 36 rounded payments is $626.74 × 36 = $22,562.64. Estimated interest is $22,562.64 − $20,000 = $2,562.64.

Assumptions

• The APR is fixed for the full repayment period.
• One payment is made at the end of each month, with the first payment one month after borrowing.
• Interest compounds monthly using APR ÷ 12.
• The estimate excludes origination and other fees, taxes, insurance, and any charges not entered as calculator inputs.

What a 3-Year Repayment Schedule Shows

A repayment schedule divides each monthly payment between interest and principal. Early in the loan, interest is calculated on a larger outstanding balance, so more of the payment goes toward interest. As the balance falls, the interest portion generally shrinks and more of each level payment reduces principal. Across 36 payments, the schedule is designed to bring the balance to approximately zero, subject to the lender’s precise rounding and payment rules.

For the example, the first month’s approximate interest is $20,000 × 0.08 ÷ 12 = $133.33. Subtracting that from the $626.74 payment leaves about $493.41 to reduce principal, giving an estimated remaining balance of $19,506.59 after the first payment. These are illustrative, rounded figures; the calculator provides aggregate totals rather than a complete month-by-month table.

When to Use This Estimate

Use the calculation to understand the arithmetic of a 36-month, fixed-rate repayment plan or to check how a quoted principal and APR translate into a regular payment. It can also provide a baseline for comparing schedules with different inputs, provided you change one assumption at a time and use the same calculation method. It does not establish whether a loan is suitable, available, or affordable for any person.

Enter the amount actually financed, not necessarily the cash amount received if a lender adds charges to the balance. Enter the APR supplied in the lender’s disclosure rather than a rate found elsewhere. APR may account for some borrowing costs differently from the nominal interest rate, and this simple formula treats the entered APR as the annual rate used to calculate monthly interest. Confirm with the lender how its payment schedule handles fees and timing.

How to Read the Result

The monthly payment is a level-payment estimate, not a promise of the amount due. Total payments multiply that rounded monthly amount by 36; estimated interest is what remains after subtracting the original principal. Because the monthly payment is rounded to cents, the final installment in a real account may be adjusted slightly to clear the remaining balance.

The schedule does not show a lender’s account ledger or provide exact daily interest. Actual balances can vary with payment dates, late or partial payments, extra principal payments, rate changes, fees, and the lender’s rounding conventions. If a lender gives a payment quotation or amortization table, compare its stated assumptions with these inputs before interpreting a difference.

Common Calculation Mistakes

A frequent error is dividing APR by 12 and entering the result as a percentage instead of using a monthly decimal. For an 8% APR, the monthly decimal is 0.08 ÷ 12, or approximately 0.0066667; the calculator performs this conversion as APR ÷ 1,200. Another error is treating three years as three payments rather than 36 monthly payments.

Rounding the monthly payment too early can also change the total. This calculator rounds the payment to the nearest cent and then multiplies that exact displayed amount by the number of months. It does not model a final payment adjustment, so do not treat the calculated total as a lender payoff quote.

Limits of the Formula

The formula applies to a fixed-rate loan with equal monthly payments and monthly interest. It is not designed for variable rates, interest-only periods, irregular payment dates, balloon payments, deferred payments, or payment schedules with fees folded into the balance. The estimate also does not model extra payments, so those would alter the timing of principal reduction and total interest.

Use the lender’s disclosed payment, APR, fee details, and amortization schedule for account-specific figures. This calculator is educational arithmetic, not financial advice. The result is an estimate, and the lender’s disclosure gives the exact figures.

Frequently Asked Questions

How many payments are in a three-year personal loan schedule?
A schedule with monthly installments over three years has 36 payments, assuming payments begin one month after the loan is made and continue monthly.

Does the monthly payment include interest?
Yes. The estimated level payment includes both principal repayment and interest under the stated fixed-rate, monthly-payment assumptions.

Why can a lender’s payment differ from this estimate?
Differences can result from fees, the rate used in the lender’s calculation, payment dates, rounding, or other contract terms not represented here. Check the lender’s disclosed assumptions.

Does paying extra reduce the interest shown?
This calculator assumes only the scheduled payment. Extra principal payments can change the balance and payoff timing, but their effect is not included in these totals.

Is the total interest guaranteed?
No. It is an estimate based on the entered APR and fixed monthly schedule. The account’s actual charges and final payment depend on the loan terms and payment history.

Final Thoughts

A three-year schedule turns a loan amount and APR into an estimated monthly payment, total interest, and total of payments over 36 installments. Treat the figures as a transparent calculation to review alongside the lender’s official disclosure, not as a quote or a recommendation.

Related

• Personal Loan APR Comparison Calculator and Guide
• Personal Loan APR Rates History and Payment Calculator
• Personal Loan APR Explained: Payments and Total Cost

in p | Loan amount | $ | 20000 | 1 | 100000000
in apr | Interest rate (APR) | % | 8 | 0.01 | 100
in yrs | Loan term | years | 3 | 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
out tot | Total of payments | $ | pmt * yrs * 12 | 2