Stripe, Adyen, and Square fee math for SaaS teams

The cumulative cost of Stripe

Stripe’s 2.9% + $0.30 online rate includes payments via Apple Pay, Google Pay, and Link. After adding Stripe Billing at 0.7%, Stripe Tax at 0.5%, and international fees, the effective rate for global software sellers lands between 7.2% and 11.7%. A US seller collecting USD from a UK cardholder pays the 1.5% international card fee but avoids the 1% currency conversion fee, though the total cost still climbs because Stripe calculates its 2.9% fee on the full transaction amount including any sales tax or VAT. Stripe also charges $15 for every dispute, and this fee is non-refundable even if the merchant wins the case. To improve usage billing for AI-scale companies, Stripe paid $1 billion for Metronome in January 2026. For B2B users, ACH Direct Debit costs 0.8% and stays capped at $5. Manual entry for cards costs 3.4% + $0.30. Marketplace teams using Stripe Connect pay $2 per month per active account plus 0.25% and $0.25 per payout. Radar for Fraud Teams costs between $0.02 and $0.07 per screened transaction. The 0.7% fee for Stripe Billing covers recurring billing, usage metering, Smart Retries, dunning, quotes, and multi-phase subscription schedules. This cumulative cost, which some developers call the "Indie Tax," grows as the business expands across Stripe’s 47 supported countries.

Finding the Adyen crossover

You likely already know that flat-rate pricing favors small merchants with low transaction counts. For SaaS teams processing under $500,000 per month, Stripe and Square provide nearly identical costs at 2.9% + $0.30 for online transactions. Adyen uses an interchange++ model, charging 0.60% plus $0.13 for Visa and Mastercard transactions. This model delivers significant savings once monthly volumes reach the $750,000 to $1.2 million range. Adyen requires a $120 monthly minimum fee and a 6-to-12-week onboarding process. A loss at scheme arbitration for an Adyen merchant can add a fee of up to $600. Adyen also charges an FX margin of 0.3% to 0.8% on foreign exchange. Unlike Stripe, which acts as an aggregator, Adyen is a direct acquirer that handles online, in-app, and in-store payments through one integration. High-volume Adyen users can see effective rates between 1.7% and 2.1%. Will the operational lift of managing an enterprise account justify these savings at your current scale? Adyen wins for high-volume merchants needing the lowest possible effective rate.

Square and operational limits

Square provides a 2.9% + $0.30 rate for online API payments, but its subscription and invoice fee sits higher at 3.3% + $0.30. Square only operates in eight countries, which limits its utility for global SaaS teams compared to Stripe or Adyen. Square also lacks a marketplace split payment tool like Stripe Connect or Adyen Platforms. Square’s manual entry rate is 3.5% + $0.15 per transaction.

Square hardware only works with its own platform. For manual entry, Square charges 3.5% + $0.15 per transaction. Square for Restaurants costs $60 per month, while Square Payroll costs $35 per month plus $5 per employee. Square for Retail Plus costs $89 per month. Square’s software costs rise independently of processing fees. The first magstripe reader is free, but the Square Terminal costs $299 and the Square Register costs $799.