Payment calculator: solve payment, loan amount, term or rate
Choose the value you need and enter the other three loan terms. HitEquals solves the fixed-rate amortization equation, shows total interest and produces the complete monthly schedule used to reach the answer.
Inputs used by this calculator
Payment Calculator uses the fields below. The starting values reproduce the page example; replace them with values from the same units and time period before using the result.
| Input | Starting example | Accepted value | How it is used |
|---|---|---|---|
| Solve for | Monthly payment | Monthly payment · Starting principal · Loan term · Annual interest rate | Chooses which Payment Calculator method or unknown the engine evaluates. |
| Starting principal | 25,000 | 0.01 to 1000000000000 | Supplies the starting principal quantity used by the published equation or result breakdown. |
| Annual interest rate (%) | 7 | 0 to 100 | Supplies the annual interest rate (%) quantity used by the published equation or result breakdown. |
| Loan term (years) | 5 | 0.0833333333 to 100 | Supplies the loan term (years) quantity used by the published equation or result breakdown. |
| Monthly payment | 500 | 0.01 to 1000000000000 | Supplies the monthly payment quantity used by the published equation or result breakdown. |
Choose what to calculate
Monthly payment answers what equal installment retires the balance on time. Principal answers how much can be borrowed for a target payment. Term answers how long a chosen payment needs. Rate estimates the annual note rate consistent with the other inputs.
- Select the unknown under Solve for.
- Enter the remaining three values.
- Review the solved value and total interest.
- Open or download the amortization schedule.
Fixed monthly payment formula
A fully amortizing fixed-rate payment depends on principal P, monthly rate r and total payment count n. At a zero rate, principal is divided evenly across n payments.
payment = P × r ÷ (1 − (1 + r)⁻ⁿ)r = annual interest rate ÷ 12 ÷ 100zero-rate payment = P ÷ nSolve principal, term or interest rate
The principal formula discounts the planned stream of equal payments. The term formula finds how many monthly payments are required; it rounds up because a partial final month still needs a payment date. Rate mode uses a bounded numerical search and reports an error when the inputs imply a rate outside 0% to 100%.
When solving the term, the monthly payment must exceed that month's interest or the balance can never decline.
How amortization changes each payment
The CFPB explains that each scheduled payment is split between interest and principal. Early in a typical amortizing loan, a larger share goes to interest; as the balance falls, interest declines and more of the same payment reduces principal.
The final row may be smaller by a few cents or dollars because the remaining balance is below the regular payment.
Interest rate, APR and excluded costs
The note interest rate drives this payment formula. APR is a broader standardized cost measure that can include certain charges, so it can differ from the interest rate and should be compared separately.
The estimate omits origination fees, closing costs, taxes, insurance, optional products, variable-rate changes and penalties. Use the lender disclosure for an actual obligation.
What the Payment Calculator answers
Solve a fixed-rate loan for monthly payment, principal, term or interest rate.
Use Payment Calculator when you know Solve for, Starting principal, Annual interest rate (%), Loan term (years) and Monthly payment and need the relationship expressed by the published equation.
What each solve mode requires
| Solve for | Known inputs | Main result |
|---|---|---|
| Payment | Principal, rate, term | Monthly payment |
| Principal | Payment, rate, term | Starting loan amount |
| Term | Principal, rate, payment | Years and exact months |
| Rate | Principal, term, payment | Annual note rate |
Frequently asked questions
How is a monthly loan payment calculated?
It amortizes principal over the number of monthly payments using the monthly interest rate.
Can I calculate the loan amount from a payment?
Yes. Select Starting principal and enter payment, rate and term.
Why must payment exceed monthly interest?
Otherwise no principal is repaid, so the balance never reaches zero.
Can this solve the interest rate?
Yes, for inputs implying an annual rate from 0% through 100%. The result is a numerical estimate.
Is the calculated rate the APR?
No. It is the note rate used in the payment equation; APR can include certain finance charges.
What question does this Payment Calculator answer?
Solve a fixed-rate loan for monthly payment, principal, term or interest rate.
What to keep in mind
Models one fully amortizing fixed-rate loan. Fees, taxes, insurance, changing rates, late charges and prepayments are excluded.
Results are rounded for display in US format, with money in dollars and cents; CSV exports keep full calculation precision. This is a calculation summary, not an official certificate.