Amortization Schedule
| Pmt # | Payment | Principal | Interest | Balance |
|---|
A Loan Calculator helps you estimate your monthly loan payment, total interest, and total amount paid over the repayment period. Enter the loan amount, interest rate, and loan term to see how much the loan may cost.
This is useful when you are comparing loan amounts, repayment terms, or interest rates before applying for financing. In this guide, you’ll learn how the calculator works, how loan payments are calculated, how interest affects your payment, and how to compare different loan options.
Key Takeaways
- A loan calculator can estimate your monthly payment, total interest, and total repayment amount for a fixed-rate installment loan.
- A longer loan term usually lowers the monthly payment but increases the total interest paid.
- The monthly payment depends mainly on the loan amount, interest rate, and number of payments.
- An amortization schedule shows how each payment is divided between principal and interest.
- Comparing total interest, not just the monthly payment, can give you a clearer view of the loan cost.
What Does a Loan Calculator Do?
A Loan Calculator estimates the payment required to repay a fixed-rate installment loan over a selected period. You enter the amount borrowed, annual interest rate, and repayment term, and the calculator estimates the monthly payment. The result can help you answer practical questions before you borrow money.
For example, you can check whether a $20,000 loan fits your monthly budget, compare a three-year term with a five-year term, or see how a higher interest rate changes the cost.
Many loan calculators can show an amortization schedule, which breaks each payment into principal and interest. The Consumer Financial Protection Bureau explains that, with an amortizing loan, the interest portion is generally larger at the start of the loan and the principal portion becomes larger as the balance falls.
How to Calculate a Loan Payment
For a fixed-rate loan with regular monthly payments, the monthly payment can be calculated from the loan amount, monthly interest rate, and total number of monthly payments.
Formula
Where:
- PMT = monthly loan payment
- P = principal, or original loan amount
- r = monthly interest rate expressed as a decimal
- n = total number of monthly payments
To convert an annual interest rate into a monthly decimal rate:
Formula
r = Annual Interest Rate ÷ 12
If the annual interest rate is 8%, the monthly rate is:
Calculation
r = 8% ÷ 12 = 0.0066667
The loan term must be converted into the total number of monthly payments. For a five-year loan:
Calculation
n = 5 × 12 = 60
The formula assumes a fixed interest rate and regular payments. Actual loan costs can differ if a loan has fees, variable rates, irregular payment schedules, or other charges.
How Does a Loan Calculator Work?
A loan calculator takes the main loan inputs and applies the payment formula to estimate the repayment schedule.
1. Loan Amount
The loan amount is the amount you borrow from the lender. A larger principal usually produces a larger monthly payment when the interest rate and term stay the same.
For example, borrowing $30,000 generally costs more per month than borrowing $20,000 under the same rate and term.
2. Interest Rate
The interest rate is the percentage charged on the amount you owe. A higher rate generally increases both the monthly payment and the total interest paid.
Do not confuse the interest rate with the Annual Percentage Rate (APR). The Consumer Financial Protection Bureau explains that APR can include the interest rate plus certain additional loan fees, making APR useful for comparing the overall borrowing cost.
3. Loan Term
The loan term is the amount of time you have to repay the loan. A longer term can reduce the required monthly payment, but it can increase the total interest paid over the life of the loan.
The Consumer Financial Protection Bureau describes this relationship for amortizing loans: longer repayment periods can mean lower monthly payments and more interest over the full term.
4. Number of Payments
For monthly payments, the number of payments is usually the loan term in years multiplied by 12.
For example:
Calculation
5 years × 12 = 60 payments
The number of payments matters directly in the loan payment calculation.
How to Use a Loan Calculator
Using a Loan Calculator takes only a few basic inputs.
Step 1: Enter the Loan Amount
Enter the amount you plan to borrow. Use the principal amount rather than the amount you expect to spend if fees or other charges are financed separately.
Step 2: Enter the Interest Rate
Enter the annual interest rate as a percentage. Check your loan offer or lender information for the rate that applies to your loan.
Step 3: Enter the Loan Term
Enter the repayment period in months or years, depending on the calculator.
A shorter term usually produces a higher monthly payment. A longer term usually produces a lower monthly payment but can result in more total interest.
Step 4: Calculate the Payment
Select Calculate to estimate the monthly payment. The result can include the payment amount, total interest, total payments, and an amortization schedule.
Step 5: Compare Different Options
Change one input at a time and compare the results.
For example, compare:
- A lower loan amount with the same interest rate.
- A shorter repayment term with the same loan amount.
- A lower interest rate with the same loan amount and term.
This gives you a clearer view of how each change affects the loan cost.
Loan Payment Example
Suppose you borrow $20,000 at an 8% annual interest rate for 5 years, with monthly payments.
The inputs are:
- Principal = $20,000
- Annual interest rate = 8%
- Monthly interest rate = 8% ÷ 12
- Loan term = 5 years
- Number of payments = 5 × 12 = 60
Formula
Calculation
Result
The total of the 60 monthly payments is approximately:
Calculation
$405.53 × 60 ≈ $24,331.80
Using the unrounded monthly payment for the calculation gives a total of approximately $24,331.67, with approximately $4,331.67 in interest.
The small difference comes from rounding the displayed monthly payment to cents.
How Much Interest Will You Pay on a Loan?
Total interest is the amount you pay above the original principal, assuming the calculation includes only the scheduled loan payments.
For a fixed-rate loan:
Formula
Total Interest = Total Payments − Principal
Using the $20,000 example:
Calculation
Total Interest ≈ $24,331.67 − $20,000
Result
Total Interest ≈ $4,331.67
This shows why the monthly payment alone does not tell you the full cost of borrowing. Two loans can have similar monthly payments but different total interest costs if their terms or rates differ.
How Loan Term Changes the Cost
The loan term can make a large difference in both monthly payment and total interest. Consider a $20,000 loan at 8% with different repayment periods:
| Loan Term | Approx. Monthly Payment | Approx. Total Interest |
| 3 years | $626.74 | $2,562.64 |
| 5 years | $405.53 | $4,331.67 |
| 7 years | $311.66 | $6,179.26 |
A shorter term requires a higher monthly payment, but the loan is repaid sooner and the total interest is lower. A longer term can make the monthly payment easier to manage, but the borrower may pay substantially more interest over the full repayment period.
What Is an Amortization Schedule?
An amortization schedule is a payment-by-payment breakdown showing how much of each payment goes toward principal and interest. For a typical amortizing fixed-rate loan, the payment amount stays level, but the split between interest and principal changes over time. Early payments generally contain a larger interest portion. As the balance falls, more of each payment goes toward principal.
A typical schedule can show:
| Payment | Payment Amount | Principal | Interest | Remaining Balance |
| 1 | $405.53 | $272.19 | $133.33 | $19,727.81 |
| 2 | $405.53 | $274.01 | $131.52 | $19,453.80 |
| 3 | $405.53 | $275.84 | $129.69 | $19,177.96 |
The exact figures depend on the loan inputs and rounding method.
How Much Extra Payment Can Save
Extra payments can reduce the outstanding principal sooner. A lower balance can reduce the interest charged on future payments for loans where interest is calculated from the outstanding balance.
For example, adding an extra amount to regular payments can shorten the repayment period. The exact savings depend on the loan balance, rate, remaining term, payment schedule, and how the lender applies extra payments.
Check the loan agreement for any rules or charges related to early repayment before making additional payments.
Loan Calculator vs. Loan Affordability Calculator
These calculators answer different questions.
| Calculator | Main Question |
| Loan Calculator | What will my payment and total loan cost be? |
| Loan Affordability Calculator | How much can I reasonably borrow based on my finances? |
| Loan Comparison Calculator | Which loan option has the lower payment or total interest? |
| Loan Payoff Calculator | How quickly can I repay an existing loan? |
A Loan Calculator works best when you already have a loan amount, rate, and term and want to estimate the repayment cost. An affordability calculator is more useful when you are starting with a budget and want to estimate a suitable borrowing amount.
Interest Rate vs. APR
Interest rate and APR are related, but they are not the same measurement. The interest rate measures the cost of borrowing expressed as a percentage. APR can include the interest rate plus certain fees associated with obtaining the loan. The Consumer Financial Protection Bureau recommends comparing APR with APR when evaluating loan offers rather than comparing an APR with a standalone interest rate.
For a basic payment calculation, the interest rate is the rate used in the standard monthly payment formula. If your loan has fees, the calculator may need additional inputs to estimate the full borrowing cost.
What Does a Loan Calculator Show?
Depending on the calculator, the results can include several useful figures.
Monthly Payment
This is the scheduled amount paid each month under the selected loan terms.
Total Payments
This is the sum of the scheduled payments over the repayment period.
Total Interest
This is the amount paid in interest over the scheduled repayment period.
Remaining Balance
An amortization schedule can show the balance left after each payment.
Payoff Date
Some calculators use the payment schedule to estimate when the loan will be fully repaid. Bankrate’s current loan calculator, for example, presents estimated monthly payment, total loan amount paid, total interest, total loan cost, and an amortization schedule.
What Loans Can a Loan Calculator Estimate?
A general Loan Calculator can be useful for many fixed-rate installment loans.
Common examples include:
- Personal loans.
- Auto loans.
- Some mortgages.
- Debt consolidation loans.
- Other fixed-rate installment loans.
A specialized calculator may be better when the loan has extra factors such as property taxes, insurance, down payments, closing costs, trade-in values, or adjustable rates. For example, auto loan calculators can include vehicle price, down payment, trade-in value, taxes, and fees.
What a Basic Loan Calculator Does Not Include
A basic loan payment calculation may not reflect every cost associated with borrowing. Depending on the loan, you may need to account for:
- Origination fees.
- Application fees.
- Closing costs.
- Insurance.
- Taxes.
- Late-payment charges.
- Prepayment terms.
- Variable interest rates.
APR can provide a broader measure of borrowing cost when applicable, since it can include the interest rate and certain fees. Your lender’s disclosure and loan agreement should be used for the actual terms of the loan.
How to Compare Two Loan Options
When comparing loans, start with the same loan amount if possible. Then compare the interest rate, repayment term, monthly payment, and total interest.
For example:
| Factor | Loan A | Loan B |
| Loan amount | $20,000 | $20,000 |
| Interest rate | 7% | 9% |
| Term | 5 years | 5 years |
| Monthly payment | Lower | Higher |
| Total interest | Lower | Higher |
A lower monthly payment is not automatically the lower-cost loan. A longer term can reduce the monthly amount but increase the total interest. Bankrate similarly recommends looking at both monthly cost and total cost when comparing loan options.
When Should You Use a Loan Calculator?
Use a Loan Calculator before you apply for a loan if you want to estimate the payment that fits your budget.
It can be useful when you are:
- Setting a maximum borrowing amount.
- Comparing repayment terms.
- Comparing interest rates.
- Estimating total interest.
- Checking whether an advertised payment seems realistic.
- Reviewing the effect of a larger or smaller down payment when the calculator supports it.
- Considering extra payments on an existing loan.
The goal is to know the estimated cost before you commit to the loan terms.
References
Frequently Asked Questions
Does a loan calculator affect my credit score?
No. Entering loan information into a calculator does not submit a credit application or create a credit inquiry. A credit inquiry can occur when you apply for credit with a lender.
Can I use a loan calculator for a variable-rate loan?
A standard fixed-rate loan calculator may not accurately predict future payments for a variable-rate loan. Changes in the interest rate can change the payment or repayment cost.
Why can my lender’s payment differ from the calculator?
The difference can come from fees, taxes, insurance, payment timing, rate differences, rounding, or other loan terms that are not included in the basic calculation.