Loan Calculator
Calculate monthly payments, total interest, and payoff totals for a simple fixed-rate loan model.
For educational purposes only. This calculator does not provide financial advice. Actual loan terms may vary by lender.
📊 Visual Analysis
What This Calculator Does
The Loan Calculator estimates the fixed monthly payment on an amortizing loan when you enter a principal amount, an annual interest rate, and a term in months. It also shows total amount repaid and total interest over the schedule, plus a simple principal-vs-interest chart. The model assumes equal monthly payments and a constant rate for the whole term unless you enter 0% interest (in which case the payment is principal divided by months). Outputs are educational only and do not include fees, insurance, or credit underwriting.
Formula
Where:
- P = Loan principal (amount borrowed)
- r = Monthly interest rate = Annual rate ÷ 12 ÷ 100
- n = Number of monthly payments (enter term in months)
- M = Monthly payment (level payment schedule)
If r = 0, the calculator uses M = P / n (interest-free amortization of principal only).
Input Fields Explained
Loan Amount ($)
The amount you assume is fully disbursed at the start. For revolving lines of credit or staged draws products, this simple model does not apply without adjusting the principal manually.
Annual Interest Rate (%)
The annual rate you want to model, converted to a monthly rate internally. It is a user assumption, not a prediction of the rate a lender will offer.
Loan Term (months)
Total count of monthly payments. Example: 360 months equals 30 years. If you are comparing to a mortgage page that uses years, convert years to months before entering here.
Example Calculation
Illustration only: Principal $250,000, annual rate 6.5%, term 360 months.
r = 6.5 ÷ 12 ÷ 100 ≈ 0.0054167; n = 360
Apply the standard payment formula to obtain monthly M; total paid = M × n; total interest = total paid − P.
Use the live tool for exact rounded figures shown on the page.
Assumptions: No origination fees, no prepaid interest shown separately, no missed payments, no extra principal payments.
How to Read the Result
The level payment that amortizes the loan under the fixed-rate assumption you entered.
All scheduled payments summed (principal + interest). It does not include upfront cash fees paid outside the payment stream.
Total paid minus original principal; shows the interest cost of borrowing under the modeled schedule.
A high-level split between principal and interest over the full term for intuition; it is not a month-by-month amortization table.
Common Mistakes
- Mixing up months and years. This field is months; entering 30 instead of 360 dramatically changes the payment.
- Ignoring fees. Origination charges and prepaid items change cash-to-close and sometimes APR, but are not embedded in this basic payment formula.
- Assuming extra payments are built in. The schedule assumes only the contractual payment each period unless you model prepayments elsewhere.
- Treating the payment as guaranteed forever. For variable-rate products, payments after resets are not represented by a single fixed rate.
When This Calculator Is Useful
- Quickly comparing monthly payments for different principal, rate, or term assumptions
- Understanding how term length changes total interest on a simple fixed-rate loan
- Sanity-checking numbers before reading a formal amortization schedule from a lender
Limitations
- Single fixed rate for the entire term; variable-rate paths are not modeled
- No taxes, insurance, or escrow
- No late payments, deferments, or interest-only periods
- Does not determine whether you qualify for a loan
- Educational only; not financial advice
Frequently Asked Questions
How is the monthly loan payment calculated?
The payment uses the standard amortizing loan formula: M = P × r × (1+r)^n / ((1+r)^n − 1), where P is principal, r is the monthly interest rate (annual rate divided by 12 and by 100), and n is the number of monthly payments. If the annual rate is 0%, the monthly payment is simply principal divided by the number of months.
Should I choose a shorter or longer loan term?
Shorter terms usually mean higher monthly payments but lower total interest paid over the life of the loan. Longer terms reduce the monthly burden but increase lifetime interest. The right trade-off depends on cash flow, other goals, and lender options — this tool only illustrates the math for the inputs you choose.
Does this calculator include origination fees or points?
No. It models principal, rate, and term only. Fees paid upfront or financed separately change your effective cost of borrowing but are not part of this simplified payment formula.
Can I model extra principal payments here?
Not in this version. The chart and totals assume only the scheduled level payment each month. If you prepay, your actual payoff date and interest cost will be lower than shown.
Why is the term entered in months?
Many consumer and auto loans are quoted in months. If you think in years, multiply by 12 (for example, 30 years = 360 months). Using months keeps the formula consistent with a monthly payment frequency.
Does this tool predict whether I will be approved?
No. Approval depends on credit, income, collateral, and lender underwriting rules. The calculator only returns math based on the numbers you type.
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Educational Disclaimer
This calculator is for educational and informational purposes only. It does not provide investment, financial, tax, or legal advice. The results are based on the inputs and assumptions you provide and may not reflect real market conditions, fees, taxes, or risks. Always do your own research or consult a qualified professional before making financial decisions.