How buy now, pay later actually works and what it costs

Buy now, pay later services have grown to a $70 billion sector, processing roughly 1.1% of all U.S. credit card spending. For New York shoppers, BNPL appears to offer interest-free installments with minimal approval friction. The reality is more complicated. The way BNPL companies, retailers, and regulators interact creates layers of fees that consumers rarely see and obligations that have begun affecting credit scores.

BNPL services like Affirm, Klarna, Afterpay, and PayPal handle about 94% of the market. They work by letting a shopper purchase something today and split the payment into installments over weeks or months. What makes BNPL different from traditional credit is its structure: the lender immediately pays the retailer the full purchase price minus its fee, then collects from the consumer on a schedule. That fee—paid by the retailer—has become the most significant cost in the BNPL ecosystem.

How the payment structure works

The most common BNPL model is 'pay in four': a 25% down payment at checkout, then three additional 25% payments due at two-week intervals, with the final payment due roughly six weeks after purchase. A shopper buying a $400 jacket would pay $100 immediately, $100 two weeks later, another $100 in four weeks, and the final $100 in six weeks. Payments are typically deducted automatically from a linked debit card, credit card, or bank account.

This differs significantly from credit cards, where a consumer can carry a balance and pay interest from the purchase date until cleared. With BNPL's pay-in-four model, the timeline is fixed: you know precisely when each payment is due and cannot extend the terms. For longer purchases, some BNPL providers now offer 12-month or 24-month installment plans that operate similarly but stretch payments across longer timeframes—and this is where costs diverge sharply from the zero-interest four-payment option.

The merchant fees that reach consumers

BNPL companies charge retailers fees that are higher than traditional credit card processor fees. This difference matters more than it initially appears. Retailers facing consistent BNPL fees have limited options: they can raise prices on all purchases, reduce promotional discounts, or cut seasonal sales. Any of these actions effectively distributes the BNPL provider's cost across every customer, including those paying cash or with credit cards.

The Federal Reserve's research noted that BNPL reached $70 billion in transaction value in 2025, representing growth of roughly 20% per year since 2021. With rapid expansion in the sector, merchant fees have become meaningful components of retail economics, particularly in apparel and electronics where BNPL adoption is highest.

Interest rates for longer installment plans

The 'pay in four' model has remained interest-free, but the BNPL market has shifted. This reflects providers' expansion into longer-term installment products aimed at larger purchases. For these plans, annual percentage rates can reach 36.99%, comparable to high-interest credit cards.

A $2,500 purchase financed over 24 months at 36.99% APR costs roughly $1,074 in interest, compared to approximately $672 on the same purchase with a credit card carrying a 24% APR. Missing a BNPL payment can trigger a late fee of $30 or more. Earlier industry reporting indicated late fees of $7 to $8, but recent products show this has increased substantially.

Credit reporting and credit score impact

Through 2024, BNPL loans generally did not appear on traditional credit reports. That changed in 2025 and 2026. FICO, the dominant credit scoring model, began including BNPL data as of fall 2025. However, reporting remains inconsistent: Affirm began reporting payment data to credit bureaus in 2025, while Klarna and Afterpay have cautioned against reporting to credit bureaus.

On-time BNPL payments can now help build credit history. Missed payments create negative marks lasting up to seven years. For borrowers later applying for mortgages or auto loans, multiple active BNPL plans can signal financial stress. Federal Reserve research found that about 89% of financially fragile consumers made multiple BNPL purchases within a 12-month period, raising the risk of budgetary overextension.

The overspending risk

BNPL services are designed to make purchases feel less expensive by breaking them into smaller installments. Federal Reserve research identified this as a key behavioral risk. Among consumers already struggling financially, nearly 9 in 10 made multiple BNPL purchases in a year. Even among financially stable consumers, about 72% made multiple purchases. When a shopper has three or four active BNPL loans with different due dates, monthly obligations can escalate beyond what a budget allows.

CBS News analysis found that 57% of BNPL users reported buyer's remorse, feeling they had purchased something too expensive. The split-payment structure appears to ease the decision to buy but can lead to regret once the financial reality of multiple simultaneous obligations sets in.

What to consider before using BNPL

Buy now, pay later is not a single product with uniform costs. It ranges from genuinely interest-free four-payment options to expensive installment loans rivaling credit card rates. The true cost extends beyond interest and late fees to merchant charges passed along as higher prices. As of 2025-2026, BNPL affects credit scores.

Before using BNPL, determine whether you're splitting a four-payment purchase over six weeks or taking an installment loan over months. Check whether your provider reports to credit bureaus. Consider whether a credit card might offer better terms and stronger protections for the same purchase. BNPL's ease of approval has made it ubiquitous, but understanding its actual cost structure is essential to avoiding accidental debt.

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