Buy Now Pay Later Is Not Free: The Hidden Costs Merchants Bear

Last updated: April 2026

The BNPL Boom: What Merchants Need to Know

Buy Now, Pay Later (BNPL) services have exploded in popularity. Klarna, Afterpay, Affirm, PayPal Pay in 4, and Apple Pay Later are now standard checkout options for millions of consumers. By 2026, BNPL transaction volume in the US is projected to exceed $100 billion annually.

For consumers, the pitch is irresistible: split a purchase into four interest-free payments, no credit check required. But for merchants, BNPL is far from free. Behind the “zero interest” promise lies a complex fee structure that can erode margins, complicate operations, and introduce new risks.

According to Allen Kopelman, payments industry analyst: “Merchants see BNPL as a conversion tool, but they often don’t calculate the true cost. When you factor in the higher transaction fees, refund handling, and operational complexity, BNPL can be significantly more expensive than traditional payment methods.”

Hidden Cost #1: Higher Transaction Fees

The most obvious cost difference is the transaction fee. While a typical credit card transaction costs 2.9% + $0.30, BNPL providers charge significantly more:

• Klarna: 5.99% + $0.35 per transaction (varies by region)
• Afterpay: 4-6% + $0.30 per transaction
• Affirm: 4-15% depending on payment term length
• Apple Pay Later: Not disclosed, but estimated 3-5%

For a $200 order, here’s the math:

On thin-margin businesses, this difference is material. A merchant with 10% net margins who processes 30% of sales through BNPL could see their profit margin drop by 1-2 percentage points.

Hidden Cost #2: Refund Complexity

Refunds are where BNPL gets messy. Unlike a simple credit card reversal, BNPL refunds involve multiple parties and inconsistent policies:

The problem: When a customer returns an item purchased via BNPL, the refund process varies by provider:

• Klarna: Refunds go back to the customer’s Klarna account or original payment method — but if the customer has an outstanding balance, Klarna may apply the refund to that balance instead.
• Afterpay: Refunds are processed as store credit by default unless the customer specifically requests a refund to their original payment method.
• Affirm: Refunds can only be processed within 120 days of purchase, after which the customer must contact Affirm directly.

The cost: Many merchants end up refunding to store credit to avoid the operational complexity, effectively retaining the liability for the original BNPL fees while losing the sale.

Hidden Cost #3: Chargeback and Fraud Risk

BNPL transactions introduce unique fraud vectors:

• Account takeover: Fraudsters target BNPL accounts with stored payment methods. When a fraudulent purchase is made, the merchant is often liable.
• “Friendly fraud”: Customers dispute BNPL charges more frequently than credit card charges, especially when they realize they’re committed to future payments.
• Identity fraud: BNPL’s minimal credit checks make it easier for fraudsters to make purchases using stolen identities.

The chargeback process for BNPL is also more complex. Unlike credit card chargebacks where the card network provides clear guidelines, BNPL chargebacks involve the BNPL provider’s own dispute resolution process, which varies by platform.

Hidden Cost #4: Integration and Operational Overhead

Adding BNPL isn’t just about flipping a switch:

• Integration costs: Each BNPL provider requires separate API integration, testing, and ongoing maintenance. Multi-provider setups multiply complexity.
• Staff training: Customer service teams need to understand each BNPL provider’s policies to handle customer inquiries effectively.
• Reconciliation burden: BNPL transactions often settle on different timelines than credit card transactions, complicating accounting and cash flow management.
• Platform fees: Some e-commerce platforms charge additional fees or require premium tiers to support BNPL integrations.

Hidden Cost #5: Brand and Customer Relationship Risk

Perhaps the most insidious hidden cost is what merchants give up:

• Customer data: BNPL providers own the customer relationship during checkout. Merchants lose visibility into payment behavior and future purchasing patterns.
• Brand dilution: BNPL branding often dominates checkout, potentially overshadowing the merchant’s brand identity.
• Dependency risk: If a BNPL provider changes terms, experiences outages, or exits the market, merchants who’ve built their checkout experience around that provider are vulnerable.

Elaina Smith, a retail payments consultant, notes: “I’ve seen merchants get hooked on BNPL’s conversion lift, only to realize they’ve handed their most valuable asset — the customer relationship — to a third party. That’s a strategic cost that doesn’t show up on a P&L.”

When BNPL Makes Sense

Despite these costs, BNPL can be a net positive for certain businesses:

A Decision Framework for Merchants

Before adding BNPL, calculate your true cost:

1. Calculate the fee impact: If 20% of your sales shift to BNPL at 5% vs 3% credit card, what does that do to your overall payment processing cost?
2. Measure conversion lift: Do you have data showing BNPL increases checkout completion by enough to offset the higher fees?
3. Assess your customer base: What percentage of your customers are in the 18-35 demographic most likely to use BNPL?
4. Evaluate alternatives: Would a store-branded credit card or traditional financing program give you similar benefits with better economics?
5. Read the fine print: Understand each BNPL provider’s refund policy, chargeback process, and settlement timing before integrating.

Conclusion

Buy Now, Pay Later is a powerful conversion tool — but it’s not free. Merchants who add BNPL without understanding the true cost structure risk eroding margins, complicating operations, and losing customer relationships to third parties.

The key is intentionality. BNPL should be a strategic decision based on your customer demographics, average order value, and margin structure — not a checkbox you add because everyone else is doing it.

For ISOs and payment professionals, the opportunity is to guide merchants through this analysis. The merchant who understands their true BNPL cost is the merchant who makes better payment decisions — and the ISO who provides that clarity builds a stickier, more profitable relationship.