Snowballr provides financial education, not investment advice. Verify any advisor on FINRA BrokerCheck.
Free · Any loan · Full amortization

Loan calculator

Calculate the monthly payment and total cost of any fixed-rate installment loan — personal, auto, student, business. Set principal, APR, and term to see the full breakdown.

2026 rate-input guidance · Your loan agreement or current lender disclosure
Enter the annual rate from your loan documents
The estimate uses a fixed annual rate divided into monthly periods. It does not include lender fees, insurance, variable-rate changes, or a personalized offer.
Use the rate that applies to the remaining balance and term; APR, fees, and payment timing can make an actual loan differ from this estimate.

Loan payment formula

Monthly payment = P × r × (1+r)^n / ((1+r)^n − 1)

P = loan principal
r = monthly interest rate (APR ÷ 12)
n = number of monthly payments (term × 12)

The formula reverse-engineers a payment that pays off the loan in exactly n months. Early payments are mostly interest; later payments are mostly principal — that's amortization.

Common loan types at a glance

LoanTypical termTypical APRSecured?
Personal2–7 yrs8–18%No
Auto (new)3–7 yrs5.5–8%Yes (car)
Auto (used)2–6 yrs7–10%Yes (car)
Student (federal)10–25 yrs~6.5%No
Mortgage 30-yr30 yrs6.5–7.25%Yes (home)
HELOC10–20 yrs7.5–9%Yes (home)

Lower payment vs less total interest

Stretching a loan over more years drops the monthly payment but raises total interest paid. $15,000 at 10% APR: 3 years = $484/mo, $2,425 interest. 5 years = $319/mo, $4,122 interest. 7 years = $249/mo, $5,896 interest. Pick the shortest term you can afford comfortably.

Loan Calculator FAQ

What's the difference between APR and interest rate on a loan?

Interest rate is the cost of the principal only. APR includes interest plus mandatory fees (origination, discount points) expressed as one annualized rate. APR is always equal to or higher than the interest rate. Compare loans on APR.

Should I take a shorter or longer loan term?

Shorter saves interest but raises payment. Rule of thumb: pick the shortest term where the payment stays under 10% of monthly gross income. For 0% intro loans, longest term possible. For high-APR debt, shortest term you can stand.

Can I pay off a loan early?

Yes, on most loans (federal student loans, mortgages, most auto and personal loans have no prepayment penalty). Some subprime auto and older mortgages carry penalties of 1–2% of remaining balance — check your contract. Extra payments go directly to principal and shave months off the term.

How is loan interest calculated?

Most installment loans use simple interest on the declining balance. Each month: interest = balance × (APR/12); principal paid = monthly payment − interest. As balance falls, more of each payment goes to principal. This is amortization.

What credit score do I need for a good loan rate?

There is no universal score cutoff across personal, auto and mortgage loans. Pricing also depends on the lender, loan type, income, debt, collateral, term and application. Ask for written offers or Loan Estimates and compare APR, fees and payment rather than relying on a score band.

Are loans with no credit check legitimate?

Be careful with any lender that promises approval without reviewing ability to repay. Product names, APR caps and licensing rules vary by state and loan type; verify the lender, read the full fee schedule and compare the total cost before applying. A no-credit-check claim does not make a loan low-cost or safe.

Related calculators

Personal loan calculator
Unsecured personal loans.
Auto loan calculator
Car loan payment math.
Amortization calculator
Full month-by-month schedule.
Debt snowball calculator
Plan multiple loan payoff.

Methodology and editorial standards

Each calculator uses its own inputs and method. Review the labels, units and assumption notes shown with the result. Costs, taxes, fees, benefits and other factors are not modeled unless the page or calculator explicitly says they are. A fixed-rate projection is a scenario, not a forecast or personalized recommendation.

The editorial standards explain how Snowballr reviews calculators and sources. The sources index links to references used across the site. To report an error or suggest a correction, use the contact page.