No single processor has the lowest fees across all transaction types
The processor with the lowest fees depends on what you're selling, how customers pay, and your monthly volume. Stripe charges 2.9% + $0.30 per card transaction; Square charges the same; PayPal charges 2.29% + $0.30 for standard transactions but 3.49% + $0.49 for goods and services. Flat-rate processors like Clover charge a fixed percentage regardless of card type. High-volume sellers often negotiate custom rates that beat published prices. The difference between processors on a single $100 transaction might be $0.60 to $1.20, but across thousands of transactions per month, that gap widens to hundreds of dollars.
Your actual cost also includes what you're not seeing: monthly minimums, chargeback fees, PCI compliance fees, batch fees, gateway fees, and early termination penalties. A processor advertising "lowest rates" may charge $25 monthly just to keep the account open. Another may hit you with a $15 chargeback fee every time a customer disputes a charge. The lowest advertised rate is not the lowest total cost.
Key Takeaways
- Card-present transactions (in-person, chip reader) cost less than card-not-present (online, phone), so your processing method matters more than which processor you choose.
- Interchange rates—what banks charge processors—are set by Visa and Mastercard and are the same everywhere; processor markup on top of that is where fees differ.
- Monthly volume, average transaction size, and industry type (restaurants, nonprofits, high-risk goods) all change which processor is cheapest for you specifically.
- Hidden fees like chargeback costs, monthly minimums, and gateway charges often exceed the per-transaction rate, so compare the full contract, not just the headline percentage.
- Processors that let you negotiate rates—Square, Stripe, PayPal—may offer discounts if you process $10,000 or more monthly.
How processor fees actually break down
Every card transaction has two layers of cost. The first is interchange—the fee the card-issuing bank charges to the processor. Visa and Mastercard set these rates, and they're identical no matter which processor you use. Interchange for a standard credit card online purchase is typically 1.55% + $0.10, but it varies by card type (rewards cards cost more), transaction method (in-person is cheaper), and industry (nonprofits get lower rates).
The second layer is the processor markup—what Stripe, Square, PayPal, or another company adds on top of interchange. This is where processors compete. Stripe's markup is 1.35% + $0.20 on a standard online card transaction, so your total cost is roughly 2.9% + $0.30. Square's markup is identical. PayPal's standard rate is 2.29% + $0.30, which sounds lower but applies only to certain transaction types; their goods-and-services rate is 3.49% + $0.49.
Beyond per-transaction fees, check the contract for monthly minimums (often $0 to $25), chargeback fees ($15 to $100 per dispute), PCI compliance fees ($0 to $99 annually), gateway fees if you're using a separate payment form ($0 to $30 monthly), and early termination penalties (sometimes three months of average processing fees). A processor charging 2.5% per transaction but $25 monthly is more expensive than one charging 2.9% with no minimum if you process less than $1,000 per month.
Lowest fees by transaction method
In-person card payments (chip reader, tap, or swipe) have the lowest interchange because the card is physically present and the risk of fraud is lower. Interchange for in-person Visa or Mastercard is typically 0.05% to 0.55% plus a small fixed fee. Stripe and Square both charge 2.6% + $0.10 for in-person transactions, making them competitive for retail or restaurant use. Clover, owned by Square, charges 2.6% + $0.10 as well. PayPal's in-person rate is 2.7% + $0.05. The difference per $100 transaction is roughly $0.10 to $0.20.
Online card payments (e-commerce, invoice, phone order) cost more because the card is not present and fraud risk is higher. This is where most processors charge 2.9% + $0.30 or similar. Stripe, Square, and most competitors are within $0.10 of each other on a $100 transaction. PayPal's standard rate of 2.29% + $0.30 is genuinely lower here, but only if you're not selling physical goods; if you are, their rate jumps to 3.49% + $0.49.
ACH bank transfers (direct debit from a customer's checking account) are the cheapest method overall, typically 1% + $0.25 or flat $0.25 per transaction. Stripe charges 0.8% + $0.30 for ACH; Square charges 1% + $0.25. The catch: ACH takes 3 to 5 business days to settle, and customers are less likely to use it than a card. It's useful for subscriptions or invoices where speed is not critical.
Comparing total cost across volume levels
| Monthly Volume | Lowest-Cost Processor | Typical Monthly Fee | Why It Wins |
|---|---|---|---|
| Under $5,000 | Stripe or Square | $15 to $45 | No monthly minimum; per-transaction rate is all you pay. |
| $5,000 to $50,000 | Square or PayPal (goods/services) | $145 to $1,450 | Rates are similar; chargeback and gateway fees matter more. |
| $50,000 to $250,000 | Stripe, Square, or Clover (negotiated) | $1,450 to $7,250 | Volume discounts kick in; custom rates available. |
| Over $250,000 | Merchant bank or ISO (custom contract) | Varies widely | Dedicated account manager; rates often 0.5% to 1.5% below standard. |
At low volumes, the difference between processors is small—often $5 to $20 per month. At $10,000 monthly volume, a 0.2% difference in rate equals $20 per month, or $240 per year. At $100,000 monthly, that same 0.2% difference is $200 per month, or $2,400 per year. This is why high-volume sellers negotiate custom rates and why low-volume sellers should not obsess over the headline rate.
The table above shows typical total monthly costs, not just per-transaction fees. These estimates include the per-transaction rate applied to your volume plus common hidden fees. Your actual cost may vary depending on your chargeback rate, whether you use the processor's hardware, and what features you need. Use this as a starting point, then request a detailed quote from each processor showing all fees broken down.
Hidden fees that add up faster than per-transaction rates
Chargeback fees are the biggest hidden cost. When a customer disputes a charge with their bank, the processor charges you a fee to investigate and respond. Stripe charges $15 per chargeback; Square charges $15; PayPal charges $20 to $25. If you process 1,000 transactions per month and your chargeback rate is 1% (high but not unusual for high-risk goods or digital products), you're paying $150 to $250 monthly just in chargeback fees on top of your per-transaction rate. Some processors offer chargeback protection or lower fees if your chargeback rate stays below a threshold.
Monthly minimums and account fees vary widely. Stripe has no monthly minimum. Square has no monthly minimum. PayPal has no monthly minimum for standard accounts. Clover charges $0 to $50 monthly depending on the plan. Some merchant banks charge $25 to $100 monthly just to keep the account active. If you process less than $500 per month, a $25 monthly minimum adds 5% to your total cost.
Gateway fees apply if you use a separate payment form or shopping cart (like WooCommerce, Shopify, or a custom form) instead of the processor's built-in checkout. Stripe charges $0 if you use their hosted checkout but $29 per month if you use Stripe.js or a custom integration. Square charges $0 for their standard form. PayPal charges $0. If you're using a third-party cart, check whether the processor charges extra to integrate.
PCI compliance fees are annual charges to maintain security standards. Stripe and Square include PCI compliance in their service at no extra cost. PayPal charges $0. Some merchant banks charge $50 to $99 annually. This is a small cost but worth confirming before signing.
When to negotiate rates and how
Stripe, Square, and PayPal all negotiate rates if you process $10,000 or more monthly. Contact their sales team (not support) and tell them your monthly volume, average transaction size, and current processor. They will often beat a competitor's rate by 0.1% to 0.3% to win your business. At $50,000 monthly volume, a 0.2% reduction saves $100 per month, or $1,200 per year.
Larger processors like Clover, Authorize.Net, and merchant banks (Chase Paymentech, First Data, Global Payments) are more flexible on rates than Stripe or Square. They expect negotiation and often have account managers who can customize contracts. If you're processing over $100,000 monthly, get quotes from at least three of these before committing.
When negotiating, ask for the following in writing: per-transaction rate for each payment method (card-present, card-not-present, ACH), monthly minimum (if any), chargeback fee, gateway fee, PCI fee, early termination penalty, and how long the rate is locked in. A verbal promise of a lower rate means nothing if the contract says otherwise.
Lowest-cost processors by use case
Online retail (e-commerce): Stripe or Square. Both charge 2.9% + $0.30 for card-not-present transactions, have no monthly minimum, and include PCI compliance. Stripe's API is more flexible if you need custom checkout; Square's dashboard is simpler if you don't. At low volume, they're identical in cost.
In-person retail or restaurants: Square or Clover. Both charge 2.6% + $0.10 for in-person transactions and offer hardware (card readers, registers) at reasonable cost. Clover's ecosystem is more closed; Square integrates with more third-party apps. For pure processing cost, they're the same.
Invoicing and subscriptions: Stripe or PayPal. Stripe charges 2.9% + $0.30 per invoice payment; PayPal charges 2.29% + $0.30 for standard invoices. If you're billing recurring subscriptions, Stripe's subscription API is more robust. PayPal's interface is simpler for one-off invoices.
Nonprofits: PayPal Giving Fund or Stripe for Nonprofits. Both waive their processor markup (you pay only interchange, typically 1.55% + $0.10) if you're a registered 501(c)(3). This is the lowest possible rate for any processor. Clover also offers nonprofit rates but requires a separate application.
High-volume sellers ($100,000+ monthly): Merchant banks like Chase Paymentech or First Data. They negotiate custom rates, often 1.5% to 2.2% for card-not-present, and assign account managers. The application process is longer (2 to 4 weeks), but the savings at high volume justify it.
Frequently Asked Questions
Can I switch processors without losing money?
Yes, but check your contract for early termination fees. Stripe and Square have no early termination penalty. PayPal's standard agreement has no penalty either. Some merchant banks charge three months of average processing fees if you leave early. If you're switching, confirm the new processor can import your customer data and that your payment form will work with their API before you cancel the old account.
Do I have to use the processor's hardware, or can I bring my own card reader?
You can use your own reader with most processors, but rates may differ. Stripe charges 2.9% + $0.30 for online payments and 2.6% + $0.10 for in-person with any reader. Square charges the same. PayPal charges 2.7% + $0.05 for in-person with any reader. Using a processor's own hardware (Square Reader, Stripe Terminal) does not change the rate, so buy based on durability and features, not cost.
What's the difference between interchange and processor markup?
Interchange is the fee the card-issuing bank charges; it's the same at every processor and set by Visa or Mastercard. Processor markup is what Stripe, Square, or PayPal adds on top. You pay both. Interchange is typically 1.55% + $0.10 for online cards; processor markup is typically 1.35% + $0.20, for a total of 2.9% + $0.30. Processors cannot lower interchange, only their own markup.
Do ACH transfers really cost less than cards?
Yes, ACH costs 0.8% to 1% + $0.25 per transaction, compared to 2.9% + $0.30 for cards. But ACH takes 3 to 5 business days to settle, and most customers prefer cards. It's useful for subscriptions, invoices, or B2B payments where speed is not critical. Offering ACH as an option can lower your average processing cost if enough customers use it.
Should I use multiple processors to get the lowest rate on each transaction type?
Not usually. The savings from using one processor for cards and another for ACH is typically $10 to $50 per month, but managing two accounts, two dashboards, and two reconciliation processes costs time. Use one processor unless you're processing over $50,000 monthly and the savings justify the complexity. At that volume, a dedicated account manager at a merchant bank is simpler than juggling multiple platforms.