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Fixed-Rate Loan Calculator

Estimate the monthly payment and total interest for a fixed-rate installment loan.

Fixed-Rate Loan Calculator: Estimate the level monthly payment that repays a fixed-rate loan over a chosen whole-year term. Compare the regular principal-and-interest payment with total interest and all scheduled repayments. The rate stays unchanged, payments occur monthly, and the balance is intended to be fully repaid at the end of the term. Runs 100% locally in your browser with zero server file uploads.

Category: Calculators
Runs: In your browser
Cost: Free · no sign-up
Availability: Ready to use

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RESULT SHEET / 02

Monthly principal and interest payment

$4,891.54

Total interest: $43,492.22
Total of scheduled payments: $293,492.22
Number of payments: 60 months

Working formulaPayment = P × r × (1 + r)^n ÷ ((1 + r)^n − 1); at 0%, payment = P ÷ n

SCHEDULE / BOUNDED VIEW

Principal, interest, and balance

Showing the first 12 payments and the final displayed payment. The engine uses the full bounded schedule.

Month	Payment	Principal	Interest	Balance
1	$4,891.54	$3,537.37	$1,354.17	$246,462.63
2	$4,891.54	$3,556.53	$1,335.01	$242,906.10
3	$4,891.54	$3,575.80	$1,315.74	$239,330.30
4	$4,891.54	$3,595.16	$1,296.37	$235,735.14
5	$4,891.54	$3,614.64	$1,276.90	$232,120.50
6	$4,891.54	$3,634.22	$1,257.32	$228,486.28
7	$4,891.54	$3,653.90	$1,237.63	$224,832.38
8	$4,891.54	$3,673.70	$1,217.84	$221,158.68
9	$4,891.54	$3,693.59	$1,197.94	$217,465.09
10	$4,891.54	$3,713.60	$1,177.94	$213,751.49
11	$4,891.54	$3,733.72	$1,157.82	$210,017.77
12	$4,891.54	$3,753.94	$1,137.60	$206,263.83
60	$4,891.54	$4,865.18	$26.35	$0.00

ASSUMPTIONS / READ BEFORE USING

This is an educational estimate for a fixed-rate loan with monthly compounding and monthly payments.
Taxes, insurance, mortgage insurance, HOA dues, origination charges, and other costs are not included unless an input says otherwise.
Actual lender terms, APR, fees, rounding, payment dates, prepayment rules, and contracts can differ. This is not a credit offer or financial advice.

Formula and worked example

Payment = P × r × (1 + r)^n ÷ ((1 + r)^n − 1); at 0%, payment = P ÷ n

A worked example with sample values:

Inputs
Loan amount	$250,000.00
Annual interest rate	6.5%
Term	5 years

Results
Monthly principal and interest payment	$4,891.54
Total interest	$43,492.22
Total of scheduled payments	$293,492.22
Number of payments	60 months

Level payment from principal, rate and term

Let P be principal, a the entered annual interest percentage, i = a ÷ 100 ÷ 12 the monthly rate and n = 12 × term in years. Monthly payment M = P × i ÷ (1 − (1 + i)^−n). At i = 0, M = P ÷ n. Total interest is the sum of the monthly interest amounts, rather than P times the annual rate times the full term.

For an illustrative $12,000 loan at 12% for 1 year, i = 0.01 and n = 12. M = 12,000 × 0.01 ÷ (1 − 1.01^−12) = $1,066.185464, displayed as $1,066.19. In month one, interest = $120 and principal = $946.19, leaving $11,053.81. The unrounded schedule totals $12,794.23 of repayments and $794.23 interest.

Compare the rate and the total cost

OpenStax's amortisation explanation (https://openstax.org/books/principles-finance-2e/pages/8-3-loan-amortization) describes payments that retire a balance. This estimate keeps precision between months and rounds displayed money, so a contract that rounds each posting can differ by small amounts. It also assumes evenly spaced payments rather than daily interest accrual.

CFPB's interest-rate and APR guide (https://www.consumerfinance.gov/ask-cfpb/what-is-the-difference-between-a-loan-interest-rate-and-the-apr-en-733/) distinguishes the borrowing rate from broader credit cost. Enter the nominal interest rate for this payment formula. To compare early repayment, use extra payments, which holds the original scheduled payment and adds a recurring amount.

How to use it

Enter the amounts, rate and duration shown in the worked example or your own scenario.
Calculate to update the result and review the assumptions.
Compare the formula and example before using the result for planning.

Privacy & limitations

Inputs and calculations stay in your browser. No values are uploaded.

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Frequently asked questions

Does a fixed rate mean every dollar of my payment reduces principal?

No. Each payment first covers the month's calculated interest on the opening balance. The rest reduces principal. As that balance falls, the interest share becomes smaller and the principal share becomes larger, even though the regular payment remains level.

What does the payment become at a zero interest rate?

The calculation divides the loan amount by the number of months. A $12,000 loan over one year at 0% has a $1,000 monthly payment and zero modelled interest. Any separate fees would still need to be considered outside this borrowing-interest comparison.

Can the same fixed-rate estimate describe a balloon or interest-only loan?

No. This page amortises the whole principal over the stated term. An interest-only period leaves principal unpaid, and a balloon structure leaves a balance due earlier. Use balloon loan for its two-term structure and a separate schedule for interest-only periods.

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Loan assumptions