Payment Calculator
Solve for either the monthly payment or the loan term you need — whichever you're missing.
About Payment Calculator
Switch between two modes: given a loan amount, rate and term, the calculator finds your required payment using the standard annuity PMT formula. Flip to 'Loan Term' mode and enter a payment you can afford — the calculator inverts the formula to find how many months you need. Extra payments are supported in payment mode and reduce the effective payoff period.
Formulas
Monthly payment (PMT)
Monthly payment = Principal × monthly_rate / (1 − (1 + monthly_rate)^−n)
- M
- Monthly payment
- P
- Principal (loan amount)
- r
- Monthly interest rate (annual rate ÷ 12)
- n
- Total number of payments (years × 12)
Solve for term (NPER)
n = −ln(1 − P × r / M) / ln(1 + r)
- n
- Number of monthly payments
- P
- Principal
- r
- Monthly rate
- M
- Monthly payment
Worked example
With the default values below, Payment Calculator returns Monthly Payment of $495.03. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Solve Forone of Monthly Payment, Loan Term
- Monthly Payment
- Loan Amountaccepts 1–10,000,000 $
- 25,000 $
- Annual Interest Rateaccepts 0–100 %
- 7 %
- Loan Term (Years)accepts 0.5–40 years
- 5 years
- Target Monthly Paymentaccepts 1–1,000,000 $
- 500 $
- Extra Monthly Paymentaccepts 0–100,000 $
- 0 $
Results
- Monthly Payment
- $495.03
- Total Interest Paid
- $4,702
- Total Amount Paid
- $29,702
- Payoff PeriodShortened if extra payments are applied.
- 60 months
Step by step
- 1Monthly rate= 0.583333%
- 2Number of payments= 60
- 3Scheduled monthly payment= $495.03
- 4Total interest paid= $4,701.80
Assumptions and limits
- The result is derived only from the 6 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax or fees or charges into account.
- Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
- This is an estimate for general information and not professional financial, tax or legal advice. See the full disclaimer for the limits that apply to this kind of calculator.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
What does 'extra monthly payment' do?
Any amount above your scheduled payment goes directly to principal. Reducing the balance faster means less interest accrues each month, shortening the total loan life. The calculator re-runs the full amortization schedule with the extra payment to show you the true payoff date.
Why does my target payment sometimes get rejected?
A fixed monthly interest payment is due even if you pay nothing extra toward principal. If your target payment is at or below the interest portion of the first month, the loan can never be paid off. You'll see the required minimum amount in the error message.
Does this handle zero-interest loans?
Yes. When the interest rate is 0%, the payment is simply the principal divided by the number of months, and the term formula reduces to principal ÷ payment.
Can I use this for any loan type?
This calculator models a standard fixed-rate, fully-amortizing loan where every payment is the same. It works for personal loans, car loans, student loans and mortgages. It does not model interest-only periods, variable rates or balloon payments.