Loan Calculator
Calculate monthly loan payments, total interest, and view amortization schedule for mortgages, auto loans, and personal loans.
Loan Details
Additional principal payment per month
Monthly Payment
$1,580.17
Payoff: Jan 2056
Payment Breakdown:
Yearly Summary:
Loan Payment Formula
M = P × [r(1+r)^n] / [(1+r)^n - 1]
Where: M = Monthly payment, P = Principal, r = Monthly interest rate, n = Number of payments
Tips for Paying Off Loans Faster
- • Make extra principal payments when possible
- • Consider bi-weekly payments (26 half-payments = 13 monthly payments)
- • Refinance to a lower rate if available
- • Round up your payments to the nearest hundred
- • Apply bonuses or tax refunds to principal
Understanding Loan Calculations
A loan calculator helps you determine monthly payments, total interest, and the true cost of borrowing. Whether it's a personal loan, auto loan, mortgage, or any other type of financing, understanding these numbers is crucial for informed financial decisions.
Key loan components:
- Principal: The amount you borrow
- Interest Rate: Annual cost of borrowing (APR)
- Term: How long you have to repay (months/years)
- Monthly Payment: Fixed amount due each month
- Total Interest: Extra amount paid beyond principal
Types of loans:
- Secured: Backed by collateral (mortgage, auto loan)
- Unsecured: No collateral (personal loan, credit card)
- Fixed rate: Interest rate stays same
- Variable rate: Rate can change over time
Loan Payment Formula
The standard amortized loan payment formula:
Monthly Payment Formula
Where:
- M= Monthly payment
- P= Principal (loan amount)
- r= Monthly interest rate (annual rate / 12)
- n= Total number of payments (years × 12)
Calculating Total Loan Cost
Total Interest Paid:
Total Interest = (Monthly Payment × Number of Payments) - Principal
Total Cost of Loan:
Total Cost = Principal + Total Interest + Fees
Example breakdown:
- Loan: $25,000 at 6% for 5 years
- Monthly Payment: $483.32
- Total Payments: $483.32 × 60 = $28,999.20
- Total Interest: $28,999.20 - $25,000 = $3,999.20
How to Use This Calculator
Our loan calculator helps you analyze any type of loan:
- Enter Loan Details:
- Loan amount (principal)
- Interest rate (APR)
- Loan term (months or years)
- Optional - Add Fees:
- Origination fee
- Other upfront costs
- View Results:
- Monthly payment
- Total interest paid
- Total cost of loan
- Amortization schedule
Compare different scenarios by adjusting the term length or interest rate to see how they affect your payments.
Understanding Amortization
What is amortization?
Amortization is the process of spreading loan payments over time. Each payment includes both principal and interest, but the ratio changes over the loan term.
How amortization works:
- Early payments: Mostly interest, little principal
- Later payments: Mostly principal, little interest
- Total payment: Stays the same each month
Example ($200,000 mortgage at 6% for 30 years):
- Payment 1: $1,000 interest, $199 principal
- Payment 180 (year 15): $683 interest, $516 principal
- Payment 360 (final): $6 interest, $1,193 principal
This is why extra payments early in a loan save more interest than extra payments later.
Comparing Loan Terms
Shorter term (e.g., 36 vs. 60 months):
- Higher monthly payment
- Less total interest paid
- Pay off debt faster
- Better if you can afford higher payment
Longer term:
- Lower monthly payment
- More total interest paid
- Debt burden lasts longer
- More affordable monthly, but costs more overall
Example comparison ($30,000 at 7%):
- 36 months: $926/month, $3,336 total interest
- 60 months: $594/month, $5,640 total interest
- Difference: $332 lower payment, but $2,304 more interest
Strategies to Reduce Loan Costs
Shop for the best rate:
- Compare offers from multiple lenders
- Check credit unions and online lenders
- Negotiate - rates are often flexible
- Consider rate locks if rates are rising
Improve your credit score first:
- Pay down existing debt
- Dispute credit report errors
- Don't open new accounts before applying
- Higher score = lower rates
Make extra payments:
- Pay more than minimum when possible
- Make biweekly payments instead of monthly
- Apply windfalls to principal
- Check for prepayment penalties first
Choose shorter terms:
- If you can afford it, shorter = cheaper
- Even 48 vs. 60 months saves significantly
Worked Examples
Personal Loan Calculation
Problem:
Calculate payments for a $15,000 personal loan at 9% APR for 4 years.
Solution Steps:
- 1P = $15,000
- 2r = 9%/12 = 0.75% per month = 0.0075
- 3n = 4 × 12 = 48 months
- 4M = $15,000 × [0.0075(1.0075)^48] / [(1.0075)^48 - 1]
- 5M = $15,000 × [0.0075 × 1.4314] / [0.4314]
- 6M = $373.28
Result:
Monthly payment is $373.28. Total paid: $17,917.44. Total interest: $2,917.44.
Auto Loan Comparison
Problem:
Compare $25,000 auto loan at 6%: 48 months vs. 72 months.
Solution Steps:
- 148 months: M = $586.85
- 2Total (48): $28,168.80, Interest: $3,168.80
- 372 months: M = $414.32
- 4Total (72): $29,831.04, Interest: $4,831.04
- 5Difference: $172.53/month lower, $1,662.24 more interest
Result:
The 72-month loan saves $172/month but costs $1,662 more in interest. Choose based on budget vs. total cost priorities.
Impact of Extra Payments
Problem:
$20,000 loan at 8% for 5 years. What if you pay $50 extra per month?
Solution Steps:
- 1Standard payment: $405.53
- 2With extra $50: $455.53/month
- 3Standard payoff: 60 months, $4,331.80 interest
- 4With extra: ~50 months, $3,559 interest
- 5Savings: 10 months earlier, $772.80 less interest
Result:
Adding $50/month pays off the loan 10 months early and saves $772.80 in interest.
Tips & Best Practices
- ✓Always compare APR, not just interest rate
- ✓Get quotes from at least 3 lenders before choosing
- ✓Shorter terms cost less overall, even with higher payments
- ✓Check for prepayment penalties before signing
- ✓Put windfalls toward loan principal to save interest
- ✓Consider biweekly payments for long-term loans
- ✓Improve credit score before applying for major loans
- ✓Read all terms carefully - fees matter
Frequently Asked Questions
Sources & References
Last updated: 2026-01-22