Use this Simple Loan Calculator to estimate monthly payment, total interest, and total repayment for a basic fixed-rate loan. Enter the loan amount, annual interest rate or APR, loan term, optional fees added to the loan, and optional extra monthly payment to see how much the loan may cost over time.

Reviewed by: AjaxCalculators Editorial Team
Last updated: April 27, 2026
Method source: Standard fixed-rate amortized loan payment formula using loan principal, financed fees, annual interest rate, loan term, and optional extra monthly payment
Editorial standards: AjaxCalculators Editorial Policy

What This Simple Loan Calculator Calculates

This calculator estimates the main numbers for a basic installment loan:

• Monthly payment
• Amount financed
• Total interest
• Total repayment
• Effect of fees added to the loan
• Effect of an optional extra monthly payment

The live tool uses loan amount, annual interest rate / APR, loan term, fees added to loan, and extra payment per month. It is designed for simple fixed-rate loan estimates, not complex adjustable-rate, balloon-payment, credit-card, lease, or student-loan forgiveness calculations.

How the Simple Loan Calculator Works

1) Amount Financed

If fees are added to the loan, they increase the amount being financed.

Amount financed = loan amount + fees added to loan

For example, if the loan amount is $10,000 and the financed fees are $250:

Amount financed = 10,000 + 250 = $10,250

This matters because interest is charged on the financed amount, not just the original requested loan amount.

2) Monthly Interest Rate

The annual interest rate or APR is converted into a monthly rate before calculating the payment.

Monthly interest rate = annual rate ÷ 12 ÷ 100

For example, if the annual rate is 7.5%:

Monthly interest rate = 7.5 ÷ 12 ÷ 100 = 0.00625

3) Loan Term in Months

The calculator lets you enter the loan term in years or months. If years are selected, the calculator converts the term into months.

Loan term in months = loan term in years × 12

For example:

• 3 years = 36 months
• 5 years = 60 months
• 10 years = 120 months

4) Monthly Loan Payment Formula

For a fixed-rate amortized loan, the monthly payment is calculated with this formula:

Monthly payment = P × r × (1 + r)ⁿ ÷ [(1 + r)ⁿ − 1]

In this formula:

• P is the amount financed
• r is the monthly interest rate
• n is the number of monthly payments

If the annual interest rate is 0%, the calculator can use a simple division:

Monthly payment at 0% interest = amount financed ÷ number of months

5) Total Repayment

Total repayment is the total amount paid through all scheduled monthly payments.

Total repayment = monthly payment × number of months

If extra monthly payments are used, the actual repayment schedule may finish earlier, so total repayment should be calculated from the actual payoff schedule rather than only multiplying the base payment by the original term.

6) Total Interest

Total interest is the amount paid above the financed principal.

Total interest = total repayment − amount financed

This shows the estimated cost of borrowing before considering other costs such as late fees, taxes, insurance, penalties, or lender-specific charges.

How Extra Monthly Payments Work

The calculator includes an optional extra payment per month field. Extra payments can reduce the loan balance faster if they are applied to principal.

Total monthly payment with extra = regular monthly payment + extra monthly payment

When extra payments reduce principal, the loan can be paid off sooner and total interest can be lower.

For example, if the regular monthly payment is $200 and you add an extra $50 per month:

Total monthly payment = 200 + 50 = $250

That extra $50 may reduce the remaining balance faster. The exact payoff time and interest savings depend on the loan amount, rate, term, and how the lender applies extra payments.

Important Note About Extra Payments

Some lenders automatically apply extra payments to principal, while others may apply them to future scheduled payments unless you request principal-only treatment. Before relying on an extra-payment plan, check your loan agreement or lender policy.

If your calculator result includes extra payments, it is helpful for the live page to show:

• regular monthly payment
• monthly payment including extra
• new payoff time
• interest saved
• total repayment with extra payments

Fees Added to Loan

The calculator includes an optional field for fees added to the loan. This can represent origination fees, processing fees, financed closing costs, or similar charges.

If a fee is added to the loan, it increases the financed principal. That usually increases both the monthly payment and the total interest.

For example:

• Loan amount: $10,000
• Fees added to loan: $250
• Amount financed: $10,250

If the fee is paid upfront instead of financed, it may not increase the monthly payment, but it still affects the real cost of borrowing.

Interest Rate vs APR

The calculator field is labeled Annual interest rate / APR (%). In a simple payment estimate, the entered percentage is used as the annual rate for the loan formula.

In real lending, interest rate and APR are not always the same. The interest rate is the cost of borrowing the principal. APR may include the interest rate plus certain required fees and loan charges.

If the calculator adds fees to the loan but does not calculate a separate fee-adjusted APR, describe the result as a payment estimate rather than an official APR disclosure.

Assumptions and Important Notes

• This calculator assumes a fixed annual interest rate.
• It assumes regular monthly payments.
• It assumes fees entered in the fee field are added to the loan balance.
• It assumes extra monthly payments are available every month.
• It assumes extra payments reduce principal if the payoff impact is calculated.
• It does not calculate adjustable rates, balloon payments, skipped payments, interest-only periods, late fees, taxes, insurance, or lender penalties.
• It does not replace lender disclosures or a formal amortization schedule.
• The currency symbol changes display only and does not perform exchange-rate conversion.

Worked Example: Basic Loan Payment

Suppose you borrow $10,000 at a 7.5% annual interest rate for 5 years, with no added fees.

Step 1: Convert loan term to months
5 years × 12 = 60 months

Step 2: Convert annual rate to monthly rate
7.5% ÷ 12 ÷ 100 = 0.00625

Step 3: Use the loan payment formula
Monthly payment = P × r × (1 + r)ⁿ ÷ [(1 + r)ⁿ − 1]

Step 4: Substitute the values
P = 10,000
r = 0.00625
n = 60

Step 5: Calculate monthly payment
Estimated monthly payment ≈ $200.38

Step 6: Calculate total repayment
Total repayment = 200.38 × 60 = $12,022.80

Step 7: Calculate total interest
Total interest = 12,022.80 − 10,000 = $2,022.80

So, a $10,000 loan at 7.5% for 5 years has an estimated monthly payment of about $200.38 and total interest of about $2,022.80.

Worked Example: Loan With Fees Added

Suppose the loan amount is $10,000, and there are $250 in fees added to the loan.

Step 1: Calculate amount financed
Amount financed = 10,000 + 250 = $10,250

Step 2: Use the financed amount in the payment formula
The calculator uses $10,250 instead of $10,000 as the principal.

Step 3: Interpret the result
Because the financed amount is higher, the monthly payment and total interest will usually be higher than a loan with no financed fees.

This is why fees should be included when comparing loan offers.

Worked Example: Extra Monthly Payment

Suppose the regular monthly payment is $200.38, and you add an extra $50 per month.

Step 1: Calculate total monthly payment
Total monthly payment = 200.38 + 50 = $250.38

Step 2: Apply the extra payment toward principal
If the lender applies the extra amount to principal, the balance falls faster.

Step 3: Estimate payoff impact
The loan may be paid off earlier than the original 60-month term.

Step 4: Estimate interest savings
Because the balance is reduced faster, less interest may accrue over the life of the loan.

Exact payoff time and savings depend on the lender’s payment application rules and the calculator’s amortization method.

How to Use This Simple Loan Calculator

1. Enter the currency symbol you want to display.
2. Enter the loan amount.
3. Enter the annual interest rate or APR percentage.
4. Enter the loan term.
5. Select whether the loan term is in years or months.
6. Enter any fees added to the loan, if applicable.
7. Enter an extra monthly payment if you plan to pay more than the required amount.
8. Click Calculate.
9. Review the monthly payment, total interest, total repayment, and any extra-payment impact shown by the calculator.

How to Interpret the Results

Monthly payment is the estimated required payment for the loan before optional extra payment.

Amount financed is the loan amount plus any fees added to the loan.

Total interest is the estimated interest cost over the repayment period.

Total repayment is the estimated total amount paid over the life of the loan.

Extra payment per month can reduce payoff time and interest cost if applied to principal.

Fees added to loan increase the financed balance and may raise both the monthly payment and total interest.

Monthly Payment vs Total Loan Cost

A lower monthly payment does not always mean a cheaper loan. A longer loan term can reduce the monthly payment but increase the total interest paid over time.

When comparing loan options, review:

• loan amount
• APR or interest rate
• loan term
• monthly payment
• fees added to the loan
• total interest
• total repayment
• whether extra payments are allowed without penalty

When This Loan Calculator Is Useful

• estimating a personal loan payment
• checking total interest before borrowing
• comparing different loan terms
• seeing how fees affect the financed amount
• estimating the impact of extra monthly payments
• planning a basic installment loan
• understanding how APR and term affect repayment
• reviewing whether a loan payment fits your budget

Common Mistakes to Avoid

• Do not compare loans only by monthly payment.
• Do not ignore total interest.
• Do not forget financed fees.
• Do not assume APR and interest rate are always identical.
• Do not enter years when the calculator is set to months, or months when it is set to years.
• Do not assume extra payments are applied to principal unless your lender confirms it.
• Do not ignore prepayment penalties, late fees, taxes, insurance, or required charges that are not included in the calculator.
• Do not treat the estimate as a lender-approved quote or official disclosure.

Formula Summary

What You Want to Find	Formula
Amount financed	Amount financed = loan amount + fees added to loan
Loan term in months	Months = years × 12
Monthly interest rate	Monthly rate = annual rate ÷ 12 ÷ 100
Monthly payment	Payment = P × r × (1 + r)n ÷ [(1 + r)n − 1]
0% interest monthly payment	Payment = amount financed ÷ number of months
Total repayment	Total repayment = monthly payment × number of months
Total interest	Total interest = total repayment − amount financed
Payment with extra	Total monthly payment = regular monthly payment + extra monthly payment
Interest saved from extra payments	Interest saved = interest without extra payments − interest with extra payments

References

1. Consumer Financial Protection Bureau: Interest rate vs APR
2. Consumer Financial Protection Bureau: Loan amortization basics
3. Consumer Financial Protection Bureau: Compare loan offers beyond monthly payment
4. Consumer Financial Protection Bureau: APR determination under Regulation Z

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Financial note: This calculator is for educational, planning, and comparison use only. It estimates basic loan payments, interest, repayment, financed fees, and optional extra-payment impact from the values entered. It does not provide financial, tax, legal, lending, accounting, or credit advice. Actual loan terms can differ because of lender rules, credit score, underwriting, APR disclosures, compounding method, repayment schedule, fees, taxes, insurance, prepayment rules, penalties, and official loan documents. For real borrowing decisions, review lender disclosures and qualified professional guidance when needed.