Calculate your monthly loan payment, total interest, and full amortization schedule. Works for personal loans, auto loans, mortgages, and student loans.
Enter loan parameters on the left, then click "Calculate Loan" to see results
We calculate the principal by subtracting your down payment from the total loan amount.
Using the principal, interest rate, and term, we calculate your fixed monthly payment.
Each payment is split between principal and interest, with early payments going more toward interest.
Formula: M = P × r × (1 + r)^n ÷ ((1 + r)^n − 1), where P = principal, r = monthly interest rate (annual rate ÷ 12), n = total number of payments.
Example: P = $20,000, APR = 7% → r = 0.07/12 ≈ 0.00583, n = 60 (5 years) → M ≈ 20,000 × 0.00583 × (1.00583)^60 ÷ ((1.00583)^60 − 1) ≈ $396.02 / month Total paid over 60 months ≈ $23,761. Total interest ≈ $3,761.
Cross-checked against authoritative formulas (IRS, NIST, ACM) and updated for 2025/2026 tax years and rates.
No server roundtrip. All math runs in your browser so results appear the moment you finish typing.
We never collect, store, or transmit your inputs. Every calculation runs locally in your browser.
Each calculator includes the formula, plain-English explanation, and FAQs so you understand the result.
Estimates only. Calculator results are for educational and planning purposes — not professional advice. For binding decisions on taxes, investments, health, or legal matters, consult a qualified professional.
Use these reference scenarios to compare typical monthly payments across the most common loan types. Adjust principal, rate, and term in the calculator above to model your exact situation.
| Loan type | Principal | APR | Term | Monthly payment |
|---|---|---|---|---|
| 30-year mortgage | $300,000 | 6.5% | 360 mo | $1,896 |
| 15-year mortgage | $300,000 | 5.75% | 180 mo | $2,488 |
| New auto loan | $35,000 | 6.0% | 60 mo | $678 |
| Used auto loan | $20,000 | 8.5% | 60 mo | $411 |
| Personal loan | $15,000 | 10.5% | 48 mo | $381 |
| Student loan | $40,000 | 5.5% | 120 mo | $434 |
| HELOC (interest-only) | $50,000 | 7.5% | — | $313 |
FAQ
Everything you need to know about this calculator. Can't find what you're looking for? Email our team.
The standard formula is M = P × r × (1 + r)^n ÷ ((1 + r)^n − 1), where P is the principal, r is the monthly interest rate (annual rate ÷ 12), and n is the number of monthly payments. For a loan with no interest, the formula simplifies to M = P ÷ n.
How it works
Use the standard amortization formula or our calculator above to find the monthly payment for any fixed-rate installment loan.
Type the total amount you are borrowing (the principal). For a $25,000 auto loan, enter 25000.
Use the loan's APR (not the rate divided by 12 — enter the full annual rate). For example, type 6.5 for a 6.5% APR.
Type the loan length in years (or months). A 5-year auto loan is 5; a 30-year mortgage is 30.
The calculator instantly shows the monthly payment, total interest paid, and full amortization schedule. Adjust any input to compare scenarios.
Walk through the monthly payment formula with a worked example for a $20,000 personal loan at 7% over 5 years.
Learn how loan amortization works, why early payments are mostly interest, and how to save money.
Learn what APR is, how it differs from interest rate, and why it matters for monthly payment calculations.