About the APR Calculator
A loan’s quoted (“nominal”) interest rate describes only the interest charge. The APR standard — required on most consumer loans in the US — folds origination fees, points and certain other finance charges into the effective annual cost. That single figure lets you compare Loan A at 6.0% with $900 of fees against Loan B at 6.3% with $200 of fees, which is precisely the decision borrowers face.
The gap between interest rate and APR is the clearest signal of how fee-heavy an offer is — so it also gives insight into which lender is profiting on fees versus on rate.
The formula behind it
The APR is the rate that equates payments at the interest rate to the net amount actually received:
Loan amount − fees = Σ payment / (1+i)^k , k = 1…ni is the APR you are solving for (annually, but iterated monthly). When i is higher than the nominal rate r, it reflects the fees. The tool finds i by a numeric solve (bisection), which is the same standard loan pricing math underwriters use.
Worked example
Defaults — $20,000 over 5 years at a 6.5% nominal rate, with a $400 upfront fee:
- The monthly payment for $20,000 at 6.5% over 60 months is about $391.31.
- You finance $19,600 of that (the $20,000 loan minus $400 of fees), yet repay $20,000 + interest.
- Pricing those same payments against $19,600 of money received solves to an APR of about 7.36%.
Takeaway: An 86-basis-point APR gap on a $400 fee — the fee costs more than 11% of its face amount over the life of the loan. Big fees cost even more in relative terms on shorter terms.
What moves the result
- Fee size — larger fees push APR higher than the nominal rate, especially on shorter terms.
- Term length — the same fee is diluted across more months on a longer loan, so APR converges downward with term.
- Rate displayed — where the rate is quoted high and the fees are low, you might skip the APR comparison entirely.
- Whether the fee is financed — fees rolled into the loan look smaller and cost more interest.
Practical tips
- When comparing loans, rank by APR, not headline rate. Payment-based comparisons erase fee differences.
- For identical amounts and terms, do rate-vs-fee sensitivity: reducing fees by 0.25% is usually worth more than reducing APR by a tiny amount.
- Prepayment changes split fees further: the same fee on a 60-month loan is cheaper APR-wise than on a 24-month loan.
- Watch how the loan is structured. Zero-promotion APR offers hide fees — run the numbers on everything before accepting convenience.
- As a shortcut, APR gap tells you all you need about “is this offer honestly priced” — 1%+ of APR/fee gap across otherwise similar quotes usually means fee-heavy.
Frequently asked questions
Why is APR higher than the interest rate?
It folds one-time fees (origination, points, some closing costs) into the annualized rate. The difference equals exactly what those charges cost you over the term.
Can APR ever be deliberately lower than rate?
Not with the way fee-inclusive APR is defined for consumer loans. On some mortgages, prepaid interest can distort the number slightly at the margin, but a lower APR than rate is essentially not normal or comparable.
Does the tool support mortgage and auto quotes?
Yes — the mechanics are universal for any amortizing fixed-rate loan, whatever its type. Just enter the offered rate, term, and fees.