Quick answer
A fixed-rate loan is repaid in equal monthly payments. Enter the loan amount, the annual interest rate (APR) and the term, and the calculator returns the monthly payment, the total interest and the total you will pay.
The payment is the amount that exactly pays off the loan over the term, with interest charged each month on the remaining balance. Fees, insurance and taxes are not included, so a lender's quote can differ.
Related tools: Amortization Calculator: Full amortization schedule with optional extra monthly payments. Mortgage Calculator: Monthly mortgage payment with property tax, insurance and HOA. APR Calculator: Annual percentage rate of a loan once upfront fees are counted.
How to use the Loan Calculator
- Enter loan amount ($) (above 0).
- Enter interest rate (APR) (%) (between 0 and 100).
- Enter term (years) (between 0 and 50). It starts at 5.
- Press Calculate to see the result, and use Reset to start again.
| Input | What to enter | Allowed values |
|---|---|---|
| Loan amount | A number, in $ | > 0 |
| Interest rate (APR) | A number, in % | ≥ 0, ≤ 100 |
| Term | A number, in years | > 0, ≤ 50, starts at 5 |
Formula and method
Formula
M = P·i ÷ (1 − (1 + i)^−n), i = APR ÷ 12, n = months
IEEE-754 double precision; money shown to cents, rates to 4 decimals. Results are estimates, not financial advice.
Fixed-rate, fully amortizing loan with monthly compounding; excludes fees, insurance and taxes.
Worked examples
These examples are verified: each one is an automated test case that the live calculator must reproduce exactly.
Example 1
Inputs: Loan amount = 20000; Interest rate (APR) = 5; Term = 5.
| Result | Value |
|---|---|
| Monthly payment | $377.42 |
| Total interest | $2,645.48 |
| Total paid | $22,645.48 |
| Payments made | 60 |
Example 2
Inputs: Loan amount = 250000; Interest rate (APR) = 6; Term = 30.
| Result | Value |
|---|---|
| Monthly payment | $1,498.88 |
| Total interest | $289,595.47 |
| Total paid | $539,595.47 |
| Payments made | 360 |
Example 3
Inputs: Loan amount = 10000; Interest rate (APR) = 0; Term = 5.
| Result | Value |
|---|---|
| Monthly payment | $166.67 |
| Total interest | $0.00 |
| Total paid | $10,000.00 |
| Payments made | 60 |
The first line is the headline result (monthly payment). Below it the loan Calculator lists total interest, total paid and payments made, which describe the same case from other angles. IEEE-754 double precision; money shown to cents, rates to 4 decimals. Results are estimates, not financial advice.
The payment formula
With principal P, monthly rate i (the annual rate divided by 12) and n monthly payments, the payment is M = P × i ÷ (1 − (1 + i)^−n).
For $20,000 at 5% over 5 years: i = 0.05 ÷ 12 = 0.0041667 and n = 60, which gives M = $377.42. Over 60 payments that is $22,645.48, so the interest is $2,645.48.
How the term changes the cost
The same $20,000 loan at 5% APR over different terms: a longer term lowers the monthly payment but raises the total interest.
Every figure in this table comes from running this calculator, so it matches what the form returns.
| Term (years) | Monthly payment | Total interest | Total paid |
|---|---|---|---|
| 3 | $599.42 | $1,579.05 | $21,579.05 |
| 5 | $377.42 | $2,645.48 | $22,645.48 |
| 7 | $282.68 | $3,744.97 | $23,744.97 |
What happens with invalid input
These messages are produced by the calculator itself, so you know what to fix.
- Loan amount: entering "0" shows "Loan amount must be greater than 0." beside that field and no result.
- Interest rate (APR): entering "-1" shows "Interest rate (APR) must be at least 0." beside that field and no result.
- Term: entering "0" shows "Term must be greater than 0." beside that field and no result.
Choosing between the Loan Calculator and similar calculators
Each row shows what a related calculator on this site asks for and what it returns, so you can pick the one that matches your question.
| Calculator | You enter | It returns |
|---|---|---|
| [Amortization Calculator](/finance/amortization-calculator/) | loan amount, interest rate and term | Monthly payment |
| [Mortgage Calculator](/real-estate/mortgage-calculator/) | home price, down payment and interest rate | Total monthly payment |
| [APR Calculator](/finance/apr-calculator/) | loan amount, upfront fees and note rate | APR |
| [Refinance Calculator](/finance/refinance-calculator/) | current balance, current rate and current remaining term | Monthly savings |
| [Auto Loan Calculator](/finance/auto-loan-calculator/) | vehicle price, down payment and interest rate | Monthly payment |
Background: loans and mortgages
The interest rate is the cost of borrowing the principal; the APR also folds in certain fees, so a lower rate with high fees can have a worse APR. These calculators use the rate you enter and do not add fees, insurance or taxes, so add fees to the principal if you want to include them.
A fixed-rate loan is paid in equal instalments, early ones mostly interest. Extra payments go straight to principal, which shortens the loan and cuts interest; adjustable rates, escrow changes and prepayment penalties are not modelled.
Assumptions and limitations
- 0% interest divides the principal evenly
- Rate up to 100%
- Term up to 50 years
Results are estimates for planning, not financial advice. Lender terms, fees, taxes and rounding rules can change real figures, so confirm important numbers with your lender or a licensed adviser.
If a required value is empty, not a number, or outside its allowed range, the form marks that field with a message and shows no result instead of a misleading number. The automated checks deliberately try invalid entries for loan amount, interest rate (APR) and term to confirm this.
Frequently asked questions
How is a monthly loan payment calculated?
The payment equals the principal times the monthly rate, divided by one minus the monthly growth factor raised to minus the number of payments: M = P × i ÷ (1 − (1 + i)^−n). The calculator applies this to the amount, APR and term you enter.
Does the loan calculator include fees or insurance?
No. It covers principal and interest only, so fees, insurance and taxes would add to the real cost.
What does the Loan Calculator calculate?
Estimate your monthly loan payment, total interest and total cost. It returns Monthly payment, Total interest, Total paid and Payments made.
What formula does the Loan Calculator use?
M = P·i ÷ (1 − (1 + i)^−n), i = APR ÷ 12, n = months. Fixed-rate, fully amortizing loan with monthly compounding; excludes fees, insurance and taxes.
What do I need to enter in the loan Calculator?
You enter Loan amount ($), Interest rate (APR) (%) and Term (years).
How is the result rounded or limited?
IEEE-754 double precision; money shown to cents, rates to 4 decimals. Results are estimates, not financial advice. 0% interest divides the principal evenly.
What are the limits of this calculator?
0% interest divides the principal evenly. Rate up to 100%. Term up to 50 years.
What is an example of a loan result?
With loan amount 20000, interest rate (APR) 5 and term 5, the monthly payment is $377.42.
Can I rely on this calculator for a decision?
Results are estimates for planning, not financial advice. Lender terms, fees, taxes and rounding rules can change real figures, so confirm important numbers with your lender or a licensed adviser. For this calculator in particular: 0% interest divides the principal evenly.
Related calculators
- Amortization Calculator — Full amortization schedule with optional extra monthly payments.
- Mortgage Calculator — Monthly mortgage payment with property tax, insurance and HOA.
- APR Calculator — Annual percentage rate of a loan once upfront fees are counted.
- Refinance Calculator — Monthly savings and break-even time from refinancing.
- Auto Loan Calculator — Monthly car payment after down payment and trade-in.
- Loan Comparison Calculator — Compare the payment and total interest of two loans.
- FHA Loan Calculator — Monthly payment with upfront and annual mortgage insurance premiums you enter.
- Interest Rate Calculator — Annual interest rate implied by a loan amount, payment and term.
Sources
- Standard time-value-of-money relations (e.g. Brealey, Myers & Allen, Principles of Corporate Finance)
Content last reviewed 2026-11-04. Formulas and worked examples are checked by automated tests against independently computed values.