Loan Payment Calculator
Calculate your monthly loan payment, total interest, and total cost. Works for mortgages, auto loans, personal loans, and student loans.
A loan payment calculator turns three inputs — principal, annual interest rate, and term in years — into the fixed monthly payment that will fully amortize your debt by the final due date. Under the hood it runs the standard amortization formula **P = L[c(1+c)^n] / [(1+c)^n − 1]**, where L is the loan amount, c is the monthly interest rate (annual rate divided by 12), and n is the total number of monthly payments. The same math drives mortgages, auto loans, personal loans, and federal student loans, which is why one calculator can serve all of them.
What the formula hides, and what this tool exposes, is how dramatically interest vs. principal splits shift over the life of a loan. On a 30-year, $300,000 mortgage at 7%, the first monthly payment of roughly $1,996 sends about $1,750 to interest and only $246 to principal — over 87% of your money is rent on borrowed capital. Not until year 21 does the split finally flip past 50/50. That back-loaded amortization is why paying down a mortgage feels slow in the early years and accelerates near the end, and why refinancing late in a loan often saves less than expected.
Extra principal payments are the single biggest lever most borrowers have. Adding just $200/month to that same mortgage shaves roughly 6 years and around $95,000 of interest off the loan. Before prepaying, always verify there is no prepayment penalty — they're rare on conforming mortgages and federal student loans but still show up on subprime auto paper, private student loans, and older commercial notes. This free tool is for educational modeling only; for actual loan decisions, compare official Loan Estimate and Closing Disclosure documents and consult a licensed mortgage or financial professional.
Quick answer: A $250,000 loan at 6.5% over 30 years has a monthly payment of about $1,580, a total cost of roughly $569,000, and $319,000 in lifetime interest — more than the original principal. This loan calculator works for mortgages, auto, personal, and student loans; enter your amount, rate, and term below.
Inputs
Quick presetsPrincipal you are actually borrowing — sticker price minus any down payment or trade-in credit.
2026 benchmarks: mortgage 6-7.5%, auto 6-9%, federal student 5-7%, personal loans 10-18%. Use the note rate (not APR) for accurate payment math.
Standard terms: 15 or 30 years for mortgages, 3-7 for auto, 10 for student, 2-7 for personal. Shorter terms cut lifetime interest 50-70% at the cost of higher monthly payments.
Results
How to use this calculator
Enter three numbers. **Loan amount** is the principal you're actually borrowing after any down payment — for a $400k home with 20% down, that's $320,000, not $400,000. **Annual interest rate** is the nominal APR expressed as a percentage; get this from a Loan Estimate, not from promotional teaser marketing. Be sure you're using APR (which includes most fees) rather than the base note rate when comparing offers.
**Loan term** is the total number of years to amortize — 30 and 15 are standard for mortgages, 3 to 7 for autos, 2 to 7 for personal loans, 10 to 25 for student loans. Hit calculate to see your fixed monthly payment, total interest paid over the life of the loan, and total cost (principal + interest). To stress-test shorter terms or different rates, re-run side-by-side — a 15-year term often doubles the monthly payment but cuts lifetime interest by 60%+. Don't forget: taxes, homeowner's insurance, PMI, and HOA dues are not included in this payment.
Worked examples
Maria, buying her first home
Maria is purchasing a $380,000 starter home and putting down 20% ($76,000), leaving a $304,000 mortgage. At a 6.75% fixed rate on a 30-year term, the calculator shows a principal-and-interest payment of about $1,972/month, total interest of roughly $405,000, and total cost of $709,000 — meaning she pays more in interest than the house costs. Running a 15-year scenario at 6.25% gives a $2,608 payment but only $165,000 total interest, saving her $240,000 over the life of the loan if her budget can absorb the larger monthly outflow.
James, accelerating a car loan
James finances a $32,000 used SUV at 8.9% APR over 6 years (72 months). The calculator returns a monthly payment of approximately $578, with $9,616 in total interest. Curious about prepayment, he re-runs assuming he throws an extra $150/month at principal. His effective payoff drops to roughly 54 months and total interest falls to about $6,950 — a $2,666 savings. His loan contract confirms no prepayment penalty, so the strategy is pure upside once his emergency fund is funded.
Priya, consolidating with a personal loan
Priya carries $14,800 across three credit cards at an average 24% APR, paying about $420/month in minimums and barely denting principal. She qualifies for a 3-year fixed personal loan at 11.5% APR. Entering $15,000 / 11.5% / 3 years, the calculator shows a payment near $495/month and total interest around $2,800. Compared to the cards' runaway compounding, the consolidation locks in a payoff date and saves her an estimated $8,000+ over the payoff window — provided she stops re-charging the cards.
Frequently asked questions
What's the amortization formula?
P = L[c(1+c)^n] / [(1+c)^n − 1]. L is loan principal, c is the monthly interest rate (annual rate / 12), and n is the total number of monthly payments. The result P is the fixed monthly payment that reduces the balance to zero by the final payment date.
Why are early payments mostly interest?
Interest each month equals the current balance times the monthly rate. When the balance is largest (early in the loan), the interest portion dominates and principal reduction is small. As the balance shrinks, the interest share falls and more of each fixed payment goes to principal — creating the characteristic back-loaded amortization curve.
How much do extra principal payments save?
A lot. On a 30-year $300,000 loan at 7%, adding $200/month to principal cuts roughly 6 years off the term and saves around $95,000 in interest. The earlier in the loan you prepay, the bigger the impact, because you eliminate compounding on a larger outstanding balance.
What's a prepayment penalty?
A fee some lenders charge if you pay off the loan early — typically 1–3% of the outstanding balance within the first 2–5 years. Federal law bans them on most qualified mortgages and all federal student loans, but they appear on some auto, private student, and commercial loans. Always read the note before prepaying.
15-year vs 30-year mortgage — which is better?
15-year terms usually carry rates 0.5–0.75% lower than 30-year, have higher monthly payments (roughly 1.4–1.5x), and cut lifetime interest by 60–70%. 30-year offers payment flexibility and more cash flow for investing. If the gap between your mortgage rate and expected investment return is small, the 15-year often wins mathematically.
Does this include taxes and insurance?
No. The calculator shows principal and interest only (P&I). Your full monthly housing payment (PITI) also includes property taxes, homeowner's insurance, PMI if down payment < 20%, and HOA dues. These can add 25–50% on top of P&I. Budget for PITI, not just P&I.
APR vs interest rate — which should I enter?
For apples-to-apples calculation, use the note rate (the actual interest rate). APR includes most loan fees amortized over the term and is typically 0.1–0.3% higher than the note rate on a mortgage. Comparing APR across offers is the cleanest way to spot hidden fees; using note rate gives you the true monthly payment math.
How is this different from a mortgage calculator?
The math is identical — a mortgage is just a loan secured by a home. Dedicated mortgage tools add PITI components (taxes, insurance, PMI) and sometimes amortization schedules. For plain P&I on any amortizing debt — mortgage, auto, personal, or student — this general loan payment calculator is the right tool.