A customer owes you $5,000. You can accept a credit card and pay roughly $150 in processing fees. Or you can accept an ACH transfer and pay $0.30. That's a 500x difference on a single transaction — and yet most merchants default to taking cards for every payment, even the ones where ACH would be better for everyone involved.

Knowing when to push each method is one of the easiest wins in payment strategy.

What ACH actually is

ACH (Automated Clearing House) is the network that moves money directly between bank accounts in the United States. When your customer's payroll hits their checking account, that's ACH. When you pay your water bill by entering your routing and account number, that's ACH. It's the same rails that handle most business-to-business payments.

ACH is fundamentally different from card processing:

  • Money moves bank-to-bank, not through card networks
  • No card brand (Visa, Mastercard, Amex) takes a cut
  • No interchange fees — the single biggest cost in card processing doesn't exist
  • Settlement takes 1–3 business days instead of 1–2

Because there's no card network and no issuing bank taking a percentage, ACH is dramatically cheaper.

What each one costs

Direct cost comparison on a $5,000 transaction:

  • Credit card (2.9% + $0.30): about $145.30
  • Debit card, Durbin-regulated (0.05% + $0.22 interchange + processor markup): about $4–$15
  • ACH: $0.25–$1.50 flat, or 0.5%–0.8% capped at $5

Monthly cost difference on a $50,000/month volume business doing mostly B2B:

  • All credit: ~$1,450/month in fees
  • All ACH: ~$25–$75/month in fees
  • Savings by converting to ACH: $1,400+/month

Where ACH makes sense

ACH is almost always the better choice for:

  • B2B invoicing. Business payments of $1,000+ are dramatically cheaper by ACH. Your customer doesn't care how they pay; you save on fees.
  • Recurring subscriptions and retainers. Monthly fees that are consistent month over month work perfectly on ACH.
  • Rent and lease payments. Standard in commercial real estate for a reason.
  • Contractor and vendor payments. When you're receiving large invoice amounts, ACH saves thousands per year.
  • Membership dues. Gyms, professional associations, clubs — recurring fixed amounts, ideal for ACH.
  • Installment plans. Big-ticket items paid over time. A $10,000 purchase split into 12 payments costs $3.60 on ACH vs. $300+ on card.

Where ACH doesn't work

ACH is a poor fit for:

  • Point-of-sale retail. Nobody standing at your register wants to give you their routing and account number. Card or cash is the only practical option.
  • First-time customers for high-risk merchants. ACH has limited fraud protection compared to cards. A new customer paying a large amount by ACH is higher risk than the same payment by card.
  • International payments. ACH is U.S.-only. International customers need cards, wire, or a separate international payment method.
  • Transactions under $25. The flat ACH fee eats the savings on small amounts. Card is often cheaper for tickets under $15–$20.

The risk tradeoff

ACH has two risks that don't exist with cards:

  • NSF returns. If your customer's account doesn't have funds, the ACH bounces back 2–5 days later. Your bank charges $5–$25 per return, and you've already counted the sale.
  • Longer dispute window. Consumer ACH transactions can be disputed for up to 60 days (vs. 120 days on cards, but with different standards). For unauthorized transactions, the window can stretch further.

Mitigating these risks:

  • Verify accounts before large transactions. Services like Plaid and MX let customers log into their bank and confirm the account has funds and is theirs.
  • Set up ACH holds for new customers. Many processors will hold ACH funds for 5–7 days before releasing them for first-time transactions.
  • Get a signed authorization. ACH requires written authorization from the customer. A standard ACH authorization form protects you in the event of a dispute.

How to start accepting ACH

Most payment processors support ACH alongside card processing:

  • Stripe, Square, PayPal all support ACH with simple integration
  • Your existing processor probably offers ACH capability — ask
  • Dedicated ACH providers (Dwolla, GoCardless, Melio) specialize in ACH and often have better rates than generic processors
  • Your business bank may offer ACH origination directly, which is often the cheapest option of all

The setup is typically faster than setting up card processing — no EMV certification, no terminal, no card brand underwriting. You just need an ACH authorization process and a way to submit the transactions.

The bigger picture

The biggest mistake merchants make with ACH is not offering it at all. You don't have to force customers onto it — you just have to make it an option. Once you start quietly mentioning "we also accept ACH" on your invoices, the customers who care about the option will use it, and your processing costs will drop accordingly. No customer-facing friction, no lost sales, just lower fees on the payments where ACH makes sense.