Loan Calculator
Compare monthly payments and total borrowing cost across different loan amounts, rates, and repayment terms.
Monthly payment
$500
Fixed payment before optional fees or insurance.
Total interest
$4,986
Interest cost if the loan runs for the full selected term.
Total paid
$29,986
Principal plus all interest across the full repayment schedule.
Start: Start
Latest: Year 5
Final value: $0
Amortization preview
| Month | Payment | Principal | Interest | Balance |
|---|---|---|---|---|
| 1 | $500 | $346 | $154 | $24,654 |
| 2 | $500 | $348 | $152 | $24,307 |
| 3 | $500 | $350 | $150 | $23,957 |
| 4 | $500 | $352 | $148 | $23,605 |
| 5 | $500 | $354 | $146 | $23,251 |
| 6 | $500 | $356 | $143 | $22,894 |
| 7 | $500 | $359 | $141 | $22,536 |
| 8 | $500 | $361 | $139 | $22,175 |
| 9 | $500 | $363 | $137 | $21,812 |
| 10 | $500 | $365 | $135 | $21,447 |
| 11 | $500 | $368 | $132 | $21,079 |
| 12 | $500 | $370 | $130 | $20,709 |
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Understanding the calculator
How it works
A loan calculator is valuable because quoted monthly payments can be misleading without context. Two loans may feel similar on the surface while carrying dramatically different total costs depending on interest rate and term length. Searchers coming to this page typically want to compare options quickly, understand the real borrowing cost, and see how much of each payment goes toward interest versus principal over time.
Installment loans generally use an amortization formula that converts a principal balance, annual percentage rate, and repayment term into a fixed monthly payment. The monthly payment formula is only the starting point. The more useful layer is the amortization schedule, which shows how interest is front-loaded and why longer terms increase total interest paid.
The math behind it
Key formulas
Monthly Payment = P x [r(1+r)^n] / [(1+r)^n - 1]
P is the loan principal, r is the monthly interest rate (annual rate / 12), and n is the total number of monthly payments.
Total Interest = (Monthly Payment x n) - P
Multiply the monthly payment by the number of payments, then subtract the original principal to see what you paid just for borrowing.
Real-world scenarios
Practical examples
$25,000 personal loan at 8% for 5 years
Monthly payment is $507. Total paid over 60 months: $30,416. Total interest: $5,416, which is 21.7% of the original loan amount.
Same loan at 8% but stretched to 7 years
Monthly payment drops to $390, but total interest rises to $7,716. The lower monthly payment costs an extra $2,300 in interest.
Effect of rate: $25,000 for 5 years at 6% vs 10%
At 6%: $483/month, $3,999 total interest. At 10%: $531/month, $6,873 total interest. A 4-point rate difference costs nearly $3,000 more.
Getting the most value
When to use this calculator
Use a loan calculator before taking on any new debt — whether it is a personal loan, auto financing, a home equity line, or a student loan. Understanding the true cost of borrowing helps you decide whether the purchase is worth financing and which offer is genuinely the best deal.
This calculator is especially useful when comparing offers from multiple lenders. Banks and online lenders often present different rate and term combinations. Running each scenario through the calculator reveals which option costs the least over time, not just which has the lowest monthly payment.
If you already have a loan, use the calculator to model the impact of extra payments or refinancing. Seeing exactly how much interest you save by paying an extra $100/month can provide strong motivation to accelerate your payoff plan.
Expert guidance
Tips and best practices
- Focus on total cost of the loan, not just the monthly payment. Longer terms lower monthly payments but increase total interest significantly.
- Even a small interest rate reduction can save thousands over the life of a loan. Shop around and negotiate.
- Extra payments toward principal reduce total interest paid. Even occasional extra payments help.
- Compare the APR, not just the interest rate. APR includes fees and gives a more accurate borrowing cost.
- Fixed-rate loans are predictable. Variable-rate loans can save money initially but carry the risk of rising payments.
Summary
Key takeaways
- Amortization front-loads interest payments — in the early years, most of each payment goes to interest rather than reducing the balance.
- Longer loan terms reduce monthly payments but dramatically increase total interest paid.
- The annual percentage rate (APR) is a more complete measure of borrowing cost than the stated interest rate alone.
- Making extra principal payments is one of the most effective ways to reduce total borrowing costs.
- Comparing loan offers requires looking at both monthly payment and total cost over the full term.
Common questions
Frequently asked questions
How do lenders determine monthly payments?
Most installment loans use an amortization formula that blends principal and interest into a fixed monthly payment over the chosen term.
Is a longer term always better?
A longer term lowers monthly payments but usually increases total interest paid. Lower monthly cost does not mean a cheaper loan.
Can I use this for personal loans and student loans?
Yes. The same payment logic works for most fixed-rate installment loans, although fees and deferment rules can change the real total cost.
Compare personal loan providers
Pre-qualify without affecting your credit score.
| Provider | Type | Highlight | |
|---|---|---|---|
| SoFi | Online lender | No fees, unemployment protection | Check rate |
| LightStream | Online lender | Low rates for excellent credit | Check rate |
| Credible | Marketplace | Compare rates from multiple lenders | Compare rates |
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