Finance Charge Calculator
Calculate total finance charges and interest on any loan.
What this calculator does
This finance charge calculator shows the total dollar cost of borrowing rather than the rate. Enter the loan amount, the interest rate, the term in years, and any extra monthly payment, and it returns the monthly payment, the finance charge across the life of the loan, the total cost, and how much an overpayment removes.
Expressing cost in dollars rather than percentages changes how it reads. A 9.9 percent rate is an abstraction; $4,894 of finance charges on an $18,000 loan is a number you can weigh against what the money is buying. The Truth in Lending Act requires this disclosure for precisely that reason.
When to use it
Use it before agreeing to a term, which is the decision that determines the finance charge more than anything else. The same loan at the same rate over three years and five years produces two very different totals, and the monthly payment comparison obscures that entirely.
It is also the right tool for weighing a purchase against its financed cost. A $6,000 furniture package financed over five years is not a $6,000 decision — the calculator turns it into the real number. And it verifies a lender's TILA disclosure: if the finance charge in the box differs materially from what the rate and term imply, there are fees you have not been told about.
Understanding the inputs
Loan amount is the principal financed, including anything rolled in such as taxes, fees, or negative equity from a trade. Interest rate is the nominal annual rate that determines the payment.
Loan term in years is the input that drives the finance charge hardest — doubling the term on the same balance typically more than doubles the charge, because you are borrowing longer and reducing principal more slowly. The extra monthly payment field shows how much of the finance charge an overpayment eliminates, which on a mid-rate loan is usually a larger figure than borrowers expect.
How is this calculated?
Monthly Payment = P[r(1+r)^n]/[(1+r)^n-1]. Finance Charge = (Monthly Payment × n) − Loan Amount.
A worked example
Take an $18,000 loan at 9.9 percent over five years. The monthly payment is about $382, and the finance charge across the term comes to roughly $4,894 — meaning you repay about $22,894 for $18,000 of credit.
Shorten the term to three years and the payment rises to about $580, an increase of $198 a month. But the finance charge falls to roughly $2,879, saving around $2,015. Put differently, the last two years of that five-year term cost about $2,015 in charges, which is what you are paying for the lower monthly payment.
Limitations and assumptions
The calculator computes interest only. A Regulation Z finance charge also includes origination fees, points, and required insurance premiums, so the lender's disclosed figure will be higher than this one whenever fees exist. Late charges, returned payment fees, and any prepayment penalty are also excluded.
It assumes a fixed rate, monthly amortization, simple interest, and every payment made on time. Precomputed interest loans, variable rates, deferred payment periods, and credit card revolving balances all behave differently. Use the TILA disclosure or Closing Disclosure for the legally binding figure.
Common Questions
- What is a finance charge?
- Under the Truth in Lending Act it is the total dollar cost of credit — interest plus most lender fees, expressed as a single amount rather than a rate. It is one of the figures lenders must disclose in the TILA box, alongside the APR, the amount financed, and the total of payments.
- Is the finance charge the same as total interest?
- Not exactly. Total interest is what accrues on the balance. The finance charge under Regulation Z also captures loan fees, points, and mortgage insurance premiums where applicable. On a fee-free loan they match. Where fees exist, the finance charge is the larger and more complete figure.
- Why does the finance charge look so large relative to the loan?
- Because it accumulates over the whole term while the payment is spread across it. A $18,000 loan at 9.9 percent over five years carries roughly $4,894 in finance charges — 27 percent of what you borrowed — even though the monthly payment feels routine. Long terms and high rates compound that effect quickly.
- How is the finance charge calculated on a credit card?
- Usually by average daily balance: the issuer sums your balance for each day of the cycle, divides by the number of days, and applies the daily periodic rate. Because it uses daily balances, paying mid-cycle reduces the charge, and the grace period means new purchases avoid it entirely if you pay the statement in full.
- What is a prepaid finance charge?
- A fee deducted from loan proceeds at closing rather than paid over the term — origination fees and discount points are the usual examples. It reduces what you actually receive while you still repay the full principal, which is why prepaid charges raise the APR more than their size suggests on shorter loans.
- Can I reduce the finance charge after signing?
- Yes, by paying down principal faster, provided the loan uses simple interest and carries no prepayment penalty. Interest accrues on the outstanding balance, so anything that reduces it early removes the interest it would have generated. Confirm your servicer applies extra payments to principal rather than advancing the due date.
- What is the Rule of 78s?
- A method of allocating precomputed interest that front-loads it, so early payoff produces a smaller rebate than simple-interest math would give. It is prohibited on loans longer than 61 months under federal law and banned outright in many states, but it still appears in some short-term and subprime auto lending — worth checking your note for.
- Where do I find the finance charge on my loan documents?
- In the Truth in Lending disclosure box, which lenders must provide before consummation. It appears next to the APR, the amount financed, and the total of payments. On a mortgage it is on the Closing Disclosure. If the figure differs from what you expected, ask before signing rather than after.