Payment Processing Fees Compared: Stripe vs Square vs PayPal vs Cash App (2026)

If you sell anything online, payment processing fees are silently eating your margins. A 2.9% fee sounds small until you realize that's $2,900 on every $100K in revenue — and that's before the per-transaction flat fees stack up. I got tired of manually calculating these fees across different processors, so I built a set of free calculators that do it instantly. Here's what I learned about how each platform actually charges you. The Real Cost Breakdown Stripe: Simple but Adds Up Stripe charges 2.9% + $0.30 per transaction. Clean and predictable. But if you're processing lots of small transactions (think $5-10 items), that $0.30 flat fee hits hard — you're paying 6%+ effective rate on a $5 sale. Try it yourself: Stripe Fee Calculator Square: In-Person vs Online Gap Square's in-person rate (2.6% + $0.10) is competitive. But online? It jumps to 2.9% + $0.30 — same as Stripe. The real difference is Square's hardware ecosystem. If you're selling at markets or pop-ups, Square wins on convenie