Payment Gateway Comparison: Stripe vs Square vs PayPal vs Authorize.net

Every payment gateway advertises a simple rate — but the total monthly cost depends on transaction volume, average ticket size, whether you’re selling online or in-person, and monthly fees that don’t appear in the headline rate. Here’s what each gateway actually costs at real business volumes.

The four gateways at a glance

Gateway	Online rate	In-person rate	Monthly fee	Setup fee
Stripe	2.9% + $0.30	2.7% + $0.05	$0	$0
Square	2.9% + $0.30	2.6% + $0.10	$0 (Free) / $49 (Plus)	$0
PayPal	3.49% + $0.49	2.29% + $0.09 (Zettle)	$0	$0
Authorize.net	2.9% + $0.30*	2.9% + $0.30*	$25	$0

*Authorize.net’s rate is through its all-in-one pricing. When paired with a merchant account, you pay interchange-plus through the merchant account + a $0.10 gateway fee per transaction + $25/month. The interchange-plus route is cheaper above $25K/month.

Monthly cost at $10K, $50K, and $100K

These calculations assume online transactions with an average ticket of $50 (200 transactions at $10K, 1,000 at $50K, 2,000 at $100K):

Gateway	$10K/month	$50K/month	$100K/month
Stripe	$350	$1,750	$3,500
Square	$350	$1,750	$3,500
PayPal	$447	$2,235	$4,470
Authorize.net (all-in-one)	$375	$1,775	$3,525
Authorize.net (IC+ merchant acct)	$305	$1,325	$2,550

Stripe: best for developers and SaaS

Stripe’s advantage isn’t price — it’s the API. The documentation is the best in the industry, the developer experience is polished, and the ecosystem (Stripe Connect for marketplaces, Stripe Billing for subscriptions, Stripe Tax for compliance) means you can build sophisticated payment flows without a second provider.

Where Stripe costs more than it should:

1. In-person: 2.7% + $0.05 is competitive but not the cheapest. Square at 2.6% + $0.10 wins on high-ticket items, loses on low-ticket.
2. ACH transfers: 0.8% capped at $5 per transaction. Good for large invoices ($625+), but Helcim charges 0.5% capped at $6 — cheaper below $750.
3. International cards: Additional 1.5% fee on international cards + 1% on currency conversion. If 20% of your transactions are international, your effective rate is 3.4%–4.4%, not 2.9%.

Square: best for in-person retail and food service

Square owns the in-person experience. The hardware ecosystem (Square Reader at $0, Square Terminal at $299, Square Register at $799) is the most integrated in the market, and the free POS software handles inventory, employee management, and basic analytics.

Where Square falls short:

1. Account stability: Square’s underwriting happens after you start processing, not before. High-ticket transactions, volume spikes, or unusual patterns can trigger funding holds. Businesses with inconsistent volumes or large transactions ($1,000+) report more holds than with Stripe.
2. Online rates: 2.9% + $0.30 matches Stripe on paper, but Square’s online checkout has fewer customization options and no equivalent to Stripe’s Checkout Session API.
3. No interchange-plus option: Square is flat-rate only. At $50K+/month, you’re overpaying by $200–$400/month compared to interchange-plus alternatives.

PayPal: highest fees, highest buyer trust

PayPal’s 3.49% + $0.49 is the most expensive standard rate of the four. On a $50 transaction, PayPal takes $2.24 vs Stripe’s $1.75 — a 28% premium per transaction. On 1,000 transactions/month, that’s $490 in unnecessary fees.

The case for PayPal despite the cost:

1. Checkout conversion: Studies from Baymard Institute and PayPal’s own data show that offering PayPal as a checkout option lifts conversion rates 5–15% for consumer e-commerce. On $50K/month in sales, a 10% conversion lift adds $5,000/month in revenue — far more than the $485/month fee premium.
2. Buyer protection perception: Consumers trust PayPal for purchases from unfamiliar merchants. If you’re a small e-commerce brand, PayPal’s buyer protection reduces purchase anxiety.
3. International reach: PayPal operates in 200+ markets. For cross-border sales, PayPal handles currency conversion and local payment methods that Stripe doesn’t cover in every market.

The smart approach: offer PayPal as a checkout option alongside Stripe. Let price-insensitive customers who want PayPal’s buyer protection use it, but route the majority of transactions through Stripe at the lower rate.

Authorize.net: cheapest at scale with a merchant account

Authorize.net is a gateway, not a full payment solution. It sits between your website and your merchant account. When paired with a merchant account that offers interchange-plus pricing, the total cost undercuts every flat-rate provider above $25K/month.

The math at $50K/month: interchange averages ~1.8% for a mixed card portfolio, plus the merchant account markup (~0.3% + $0.10/txn), plus Authorize.net’s gateway fee ($0.10/txn + $25/month). Total: approximately $1,325/month vs $1,750 on Stripe — saving $425/month or $5,100/year.

The trade-off: setup complexity. You need to find and negotiate with a merchant account provider separately, manage two relationships instead of one, and deal with interchange-plus statements that show dozens of rate categories. If you don’t have someone who can read a processing statement, Stripe’s simplicity is worth the premium.

Which gateway for which business

1. Under $10K/month, online: Stripe. Zero monthly fee, best developer tools, clean dashboard.
2. Under $10K/month, in-person: Square. Free hardware, free POS, lowest in-person flat rate.
3. $10K–$50K/month, online: Stripe or Square, plus PayPal as a checkout option. The fee difference between Stripe and Square is negligible; choose based on integration needs.
4. $50K–$100K/month: Authorize.net + interchange-plus merchant account. Saves $4,000–$10,000/year over flat-rate. Worth the setup complexity.
5. $100K+/month: Authorize.net + negotiated merchant account, or Stripe with custom enterprise pricing (available above $100K/month — contact Stripe sales). At this volume, a 0.1% rate reduction saves $1,200/year.