What it means
An ACH payment is one of two instructions: a credit, which pushes money into an account, as with payroll, or a debit, which pulls money from one, as with a monthly subscription collection. Banks gather these instructions, pass them to an operator in batches and settle the net amounts between themselves.
For a business the appeal is cost. A card payment usually costs a percentage of the amount collected, while an ACH transfer typically costs a flat fee of a few cents to a few tens of cents whatever the size, so large invoices are dramatically cheaper to collect this way.
The trade-off is speed and reversibility. Standard ACH settles over one to a few business days, with faster same-day options available at higher cost, and unlike a wire transfer an ACH debit can be returned or disputed for a period after it lands.
Finance teams use ACH for payroll, supplier payments, customer collections by direct debit and refunds. Setting it up means capturing bank account details plus an authorisation from the payer, which is why ACH suits repeat relationships better than one-off transactions with strangers.
One point to keep straight is geography. ACH is a United States network, and other countries run their own equivalents under different names, so a business selling across borders will end up operating several payment rails rather than one.
In practice
Real-world examples.
Example
A software company billing 1,200 business customers an average of $900 a month switches its invoicing from card to ACH debit. Fees fall from roughly five figures a month to a few hundred dollars, and the saving goes straight to the bottom line because nothing else about the service changes.
Example
A staffing agency pays 400 temporary workers every Friday by ACH credit rather than by cheque. Payroll administration time drops sharply, and the agency can see exactly which accounts were credited without waiting for cheques to be banked.
Example
A commercial landlord collects rent from thirty tenants by ACH debit on the first working day of each month. Late payments fall because collection no longer depends on each tenant remembering to send money, and the accounts team reconciles one batch instead of chasing thirty transfers.
Formula
Calculation
Monthly ACH cost = (Number of transactions x Fee per transaction) + Monthly platform fee
Suppose a wholesaler collects 2,000 customer payments a month, averaging $400 each, and its provider charges a flat fee of $0.25 per ACH transaction plus a $30 monthly platform fee.
ACH cost = (2,000 x $0.25) + $30 = $500 + $30 = $530
Collecting the same payments by card at 2.9% plus $0.30 per transaction would cost:
Total collected = 2,000 x $400 = $800,000
Percentage fee = $800,000 x 0.029 = $23,200
Per-transaction fees = 2,000 x $0.30 = $600
Card cost = $23,200 + $600 = $23,800
The saving from using ACH is $23,800 - $530 = $23,270 a month, which is why high-value recurring billing almost always moves off cards.Case study
Seen in the real world.
This illustrative case is fictional. Marrowfield Supply, an invented building materials distributor, let its customers pay by card as a convenience and never looked closely at the cost. Its average invoice was $2,800, and card fees of just under 3% were quietly consuming a meaningful share of a thin gross margin.
The finance director worked out that moving the top 200 accounts to ACH debit would save around $18,000 a month in fees. The obstacle was not technology but paperwork: each customer had to supply bank details and sign an authorisation. Marrowfield solved it by offering a 1% early settlement discount to anyone switching, which was a third of the fee being saved.
Within two quarters most of the value had moved to ACH, days sales outstanding improved because collection was now scheduled rather than requested, and the discount cost less than the fees it replaced. The remaining card volume stayed in place for small one-off orders, where the convenience was worth the fee.
Watch out
Common mistakes.
- Treating ACH as instant, when standard settlement takes one or more business days and cash forecasts need to reflect that lag.
- Assuming an ACH debit is final once received, when it can be returned or disputed for a period and the cash may have to be given back.
- Collecting bank details without a clear written authorisation, which leaves the business exposed if a payer later challenges the debit.
Questions
People also ask.
Is ACH the same as a wire transfer?
No, a wire is sent individually, settles quickly and is effectively final, while ACH is batched, slower, much cheaper and reversible within limits.
Does ACH work for international payments?
Not directly, because it is a domestic United States network, so cross-border payments use other systems or a provider that bridges them.
What makes ACH payments fail?
Usually insufficient funds, a closed account, wrong account details or a missing authorisation, and a good process retries sensibly and flags repeat failures for a phone call.
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