Automated Clearing House
What is Automated Clearing House?
Automated Clearing House (ACH) is the US electronic funds transfer network that moves money directly between bank accounts in scheduled batches. It's governed by Nacha, formerly the National Automated Clearing House Association, and runs on two operators: FedACH, run by the Federal Reserve, and the Electronic Payments Network, run by The Clearing House.
ACH carries direct deposits, payroll, tax refunds, bill payments, vendor disbursements, and consumer debits such as utility bills and subscription charges. Because it's an rail, no card network sits in the middle, and entries don't carry interchange or scheme fees. Banks queue entries and exchange them at fixed cutoff times rather than authorizing each one individually within seconds, which is why an ACH transfer confirms in days rather than the moment a shopper clicks pay.
Key facts
- Also known as: the ACH network. In everyday use, "ACH" also names the payment type that travels over it (see ).
- Governed by: Nacha, which writes the operating rules that participating US financial institutions follow.
- Operators: FedACH (Federal Reserve) and the Electronic Payments Network (The Clearing House).
- Entry types: debit entries pull funds from an account, as in a ; credit entries push funds into one.
- Standard Entry Class codes: PPD for consumer entries, CCD for corporate entries, WEB for internet-authorized consumer debits. The SEC code sets the authorization requirements and the return window that apply.
- Timing: standard entries settle on the next banking day. Same Day ACH clears within the same business day, up to Nacha's per-transaction dollar limit.
- Geographic scope: United States only. is the euro-area equivalent, and cross-border bank transfers use messaging instead.
How it works
- Authorization – The Receiver authorizes the Originator to debit or credit their account. The form the authorization takes depends on the SEC code.
- Origination – The Originator submits the entry to its bank, the Originating Depository Financial Institution (ODFI), with the Receiver's routing and account number.
- Batching – The ODFI groups entries into files and transmits them to an ACH operator at a scheduled cutoff. Entries submitted after the cutoff wait for the next window.
- Sorting – The operator sorts entries by routing number and delivers each one to the Receiving Depository Financial Institution (RDFI).
- Posting and settlement – The RDFI posts the entry to the Receiver's account, and the operator settles the net position between the two banks across their Federal Reserve accounts. See for how net positions are cleared.
- Returns – An RDFI that can't post the entry sends it back with a return code, which reverses the funds movement after settlement has already happened.
Why it matters
- ACH is priced per entry rather than as a percentage of value, so the cost of collecting $5,000 is close to the cost of collecting $50. That's what makes it the default rail for payroll and B2B disbursements.
- A stored bank mandate doesn't expire or get reissued the way a card does, so subscription billing over ACH avoids the involuntary churn that comes from expired or replaced cards.
- Acceptance isn't finality. An entry that posts can still be returned days later, so an ACH collection isn't confirmed revenue at the moment it's submitted.
Common issues
- Insufficient funds and closed accounts. R01 (insufficient funds) and R02 (account closed) are the most frequent returns on debit entries, and both arrive after the entry appeared to succeed.
- Unauthorized returns. R10 covers a consumer stating the debit wasn't authorized; R29 is the corporate equivalent. Unauthorized consumer returns carry a longer window than ordinary returns, which is covered in .
- Missed cutoffs. An entry submitted after the ODFI's file cutoff sits until the next batch, which pushes settlement out by a full banking day.
- Stale account data. ACH validates the routing number format, not whether the account exists and belongs to the named Receiver, so bad account details surface only as a return.
