Square transaction fees are deliberately simple: 1.9% for all Square Reader payments and 1.6% for all Square Terminal payments regardless of the type of card and where it is from, and 2.2% for all keyed-in payments regardless of whether the merchant or customer entered their card details remotely or in person.
With Stripe, you can save money if the majority of payments are made with Australian cards because those transactions cost just 1.75% + A$0.30. International cards cost more than Square, though: 2.9% + A$0.30 per transaction. The fixed $0.30 fee could become expensive if most transaction amounts are low ($0.30 of $5 is the equivalent of a 6% fee!). In addition, Stripe charges a 2% currency conversion fee on transactions paid in a different currency from the customer’s card.
With billing, Stripe merchants pay the same transaction fees for one-off invoices as through ecommerce (1.75% + A$0.30 for domestic/2.9% + A$0.30 for international), but automatically charging customers on a recurring basis costs only 0.5% per payment.
Payouts are free on both platforms, but Square gives the option to settle transactions instantly in your bank account for an extra 1% added to transactions.
PCI compliance (card security paperwork) is managed free of charge by Square, while Stripe encourages their users to address this but with some support provided. This could cost extra depending on the level of protocols required for your business. Chargebacks cost A$25 each with Stripe, but are free with Square.