An ACH payment needs less information than most forms ask for, and one of the fields it does need is the one people most often get wrong. The list is short: the routing number, the account number, the account type, the account name, the amount and, for a debit, an authorisation that exists before the money moves. Each of those has a wrinkle worth knowing.
The routing number, and which one
ACH runs on a nine digit routing number, and at many banks it is not the same number used for wire transfers. The routing number printed on a personal check is usually the ACH one, but the bank's own page is the reliable source and several large banks publish both numbers side by side with labels. Using a wire routing number for an ACH entry generally causes a return rather than a misdelivery, which costs days rather than money, but it is entirely avoidable.
The account number and the account type
The account number has no fixed length in the United States and carries no universal check digit, which is why the routing number's own checksum does so much work. The account type matters as well: an ACH entry is marked as checking or savings, and sending a checking entry to a savings account can be rejected. Both fields come straight from the bank's account details screen, and copying rather than transcribing is worth the extra few seconds.
The name, and the authorisation for a debit
The account name is required, and a mismatch is a common cause of a return even though there is no pre payment name check equivalent to the UK one. For a debit, an authorisation has to exist before the entry is originated: the account holder has to have agreed, in a form that can be produced later. The Consumer Financial Protection Bureau publishes guidance for consumers on how such authorisations are given and withdrawn, which is worth reading from either side of the transaction.
What you do not need
You do not need the bank's address, you do not need a BIC or SWIFT code, and you do not need an IBAN. All three are fields for international payments and none of them appears in a domestic ACH entry. If a form is asking for them alongside a routing number, it is probably a generic international form rather than an ACH one, and supplying an IBAN where an account number is wanted will simply fail.
Questions people ask about what information is needed for ach payment
What is the minimum information for an ACH payment?
The routing number, the account number, the account type, the account name and the amount. A debit also needs an authorisation from the account holder.
Is the ACH routing number the same as the wire routing number?
Often not. Many US banks publish separate numbers for ACH and for wires, and using the wrong one usually causes a return.
How long does an ACH payment take?
ACH settles in batches rather than instantly, so a standard entry commonly lands the next business day, with same day options available at many institutions.
Do I need a SWIFT code for ACH?
No. ACH is a domestic US system and uses the routing number. A BIC or IBAN is only needed for payments crossing a border.