The interest rate is the cost of borrowing the principal, expressed annually. The APR is that rate plus mandatory fees, expressed as a single annualized figure. Under the federal Truth in Lending Act, U.S. lenders must disclose APR — which is precisely why you should compare on APR and nothing else.
What the gap looks like
Borrow $10,000 for 36 months:
| | Lender A | Lender B |
|---|---|---|
| Interest rate | 12.0% | 12.0% |
| Origination fee | 0% | 5% ($500) |
| Cash received | $10,000 | $9,500 |
| Monthly payment | $332 | $332 |
| APR | 12.0% | 15.6% |
| Total cost | $1,957 | $2,457 |
Same advertised rate. $500 difference. The fee is deducted up front, so you repay interest on money you never received.
Fees that count toward APR
- Origination or administration fees (1%-8% is typical)
- Documentation and processing fees
- Mandatory credit insurance, where charged
Fees that do not
- Late payment fees
- Returned payment fees
- Prepayment penalties (rare on personal loans, but check)
These do not appear in the APR, so read the fee schedule separately.
Fixed vs variable
Almost all U.S. personal loans are fixed-rate: payment and rate never change. Variable-rate personal loans exist and tie to an index; the starting rate is lower and the risk is yours. For a 3-5 year term, fixed is the default sensible choice.
The 36% line
Most reputable online lenders cap APR at 35.99%. That is not accidental — it mirrors a widely used regulatory and industry ceiling for responsible lending. Offers meaningfully above it are payday, title, or tribal products with a different risk profile.
How to compare correctly
1. Prequalify with three to five lenders using soft pulls, within a 14-day window so the eventual hard inquiries are treated as one.
2. Line up the APR, the total cost to payoff, and the cash actually disbursed.
3. Ignore monthly payment as a comparison metric — it can always be lowered by extending the term.
Model any offer with the APR calculator and the loan payment calculator.