How this instrument works
A payday loan is a small, short-term advance — often a few hundred dollars — that comes due in a single lump sum on the borrower's next payday, typically within two to four weeks. Rather than charging a periodic interest rate, the lender charges one flat fee for the whole term, secured by a post-dated check or an authorized bank debit signed at the counter. That single-fee, single-due-date structure separates a payday advance from an installment loan, and it is why the typical borrower is someone already shut out of a credit card, an overdraft line, or a cheaper source of credit.
Because the fee is fixed for the whole term instead of accruing daily, annualizing it means multiplying that rate by however many times the same term would repeat across 365 days. A two-week loan's term repeats roughly 26 times a year, so a 15% flat fee — unremarkable on a single advance — becomes a rate above 390% once expressed the way federal disclosure rules require. The formula adds nothing to that charge; it only re-expresses the same dollars on a yearly clock, which is what makes a short term look so severe next to a long-term loan charging an identical percentage.
What this sheet cannot show is what happens after a due date passes unpaid. Many state rules let a borrower who cannot repay roll the advance into a new term for another fee, and regulators have documented that a large share of payday borrowers renew several times before clearing one loan — each renewal charges the same flat amount again on a principal that never shrinks. This instrument prices one term paid on schedule; it does not chain rollovers, add a returned-item penalty, or account for the caps on that charge, which vary widely from state to state.
- Enter the cash advance amount into Loan principal, $.
- Enter the lender's one-time charge into Finance fee, % of principal — assessed once for the term, not compounded daily.
- Set Loan term, days to the number of days until the loan is due, usually your next payday.
- Read Finance fee, $ and Annualized percentage rate (APR), % — the dollar cost and its yearly-rate equivalent.
- Check Total repayment, $ — principal plus fee, the exact amount due on the loan's due date.
Worked example — a $300 advance due in 14 days
Take a $300 advance carrying a flat finance fee of 15% of principal, due in 14 days. Enter 300 into Loan principal, $, 15 into Finance fee, % of principal, and 14 into Loan term, days. The instrument multiplies principal by that rate: 300 × 0.15 = $45.00, so Finance fee, $ reads $45.00 and Total repayment, $ reads $345.00 — the exact amount owed on payday.
Annualizing that fee turns a modest-looking 15% into a very different figure: divide the $45 charge by the $300 principal to recover the 15% rate, multiply by how many 14-day periods fit inside 365 days (about 26.07), then by 100. Annualized percentage rate (APR), % reads 391.0714% — the number federal disclosure rules require the lender to print, and the reason a $45 charge on a two-week loan carries the same warning label as a triple-digit interest rate.
Questions
Why is payday loan APR so much higher than the flat fee?
Because the fee is charged once for the whole term, and annualizing multiplies it by how many times that term repeats across a year. A 15% fee due in 14 days repeats roughly 26 times annually, so 15% becomes about 391% once stretched to a yearly basis. That is straightforward multiplication, not compounding — a short term simply makes the multiplier large.
Does total repayment include more than principal and fee?
No — Total repayment, $ here is only principal plus the flat finance fee entered. Real payday paperwork can add a returned-item charge if a payment bounces, or a renewal fee if the loan is rolled over instead of repaid; this sheet totals a single on-time repayment and leaves those extra charges for you to add separately.
What happens if I can't repay by the due date?
This instrument doesn't model that outcome directly — it prices one term paid in full on schedule. Many lenders let a borrower roll the balance into a new term for another fee instead of defaulting, and each rollover charges the same amount again on the same principal, which is how one 14-day advance can accumulate several extra cycles' worth of cost without the principal shrinking at all.
Why does loan term matter more than the fee rate here?
Because APR divides the fixed fee percentage by the term in days before annualizing, so a shorter term produces a sharply higher APR for the same charge. Stretch a 15% fee from a 14-day term to a 30-day term and APR drops from about 391% to about 183%, even though the dollar amount charged and the total repaid stay exactly the same.
Who typically takes out a payday loan?
Usually someone who needs cash before a paycheck arrives and lacks access to a credit card, an overdraft line, or a family loan — payday lenders serve borrowers that mainstream credit underwriting turns away. Federal Reserve survey data on household financial fragility is one place regulators track how common that gap between paychecks actually is.
Does the loan size itself change the APR?
No — Annualized percentage rate (APR), % depends only on that rate and the term in days, not on Loan principal, $. Doubling the principal from $300 to $600 at the same 15% fee and 14-day term doubles the dollar charge too, so the ratio inside the APR formula, and the resulting rate, stays identical at about 391%.
References
- CFPB — Payday loans consumer guidance
- CFPB — What is a payday loan?
- Federal Reserve — Report on the Economic Well-Being of U.S. Households
Read this first: This instrument shows arithmetic, not advice. Real offers add fees, taxes and terms that vary by lender and place — verify the figures against your actual paperwork before deciding anything.