Guide to ACH transfers and trace numbers

Ever waited for an ACH payment that didn’t land on time? Delays happen, and when they do, your ACH trace number helps you find out where the money is and when it will clear.

An ACH trace number is a 15-digit identifier that combines the originating bank’s routing number with a sequential seven-digit code used to track ACH payments. Because different banks use the same numbering logic, trace numbers aren’t globally unique and can repeat across institutions or over time.

Understanding how ACH transfers and trace numbers work gives you better visibility into payments, helps maintain strong vendor relationships, and keeps cash flow steady.

What is an ACH transfer?

ACH transfers move money electronically between bank accounts through the Automated Clearing House (ACH) network, which connects financial institutions across the U.S. They can be credits or debits, depending on whether money is pushed to or pulled from your account.

Common ACH transactions include:

• Direct deposit payroll
• Tax refunds
• Vendor payments
• Recurring utility bills
• Subscription payments
• B2B transactions

Although ACH transfers are similar to wire transfers, they work differently. ACH payments usually take one to three days to process, often for free or at a low cost, and are best for recurring payments. Wire transfers can process within hours, come with a fee, and are better for large or urgent transactions.

The ACH network is managed by Nacha, a nonprofit that sets operating rules and ensures all transfers are processed securely and efficiently. In 2024, Nacha reported more than 40 billion ACH payments, a 7.2% increase from the previous year.

Types of ACH transfers

There are two main types of ACH transfers:

• ACH credits: When you authorize funds to be pushed into an account from another. Examples include direct deposit paychecks, paying a credit card bill from your checking account, or receiving an electronic tax refund.
• ACH debits: When money is pulled from your account by someone you’ve authorized. Examples include automatic bill pay for utilities, subscriptions, or mortgages.

ACH vs. wire transfers

ACH transfers and wire transfers are both ways to move money electronically, but they differ in speed, cost, and typical use cases.

ACH transfers are generally best for recurring payments and day-to-day business use, while wire transfers are reserved for high-value or time-sensitive transactions.

Understanding ACH trace numbers

An ACH trace number is a 15-digit code assigned by the originating financial institution to help track an electronic transaction within the ACH network. These identifiers aren’t globally unique, since each bank generates its own sequences.

ACH trace numbers allow banks to trace transactions throughout the ACH network. When payment issues arise, such as delays, rejections, or disputes, they serve as the key reference point for investigation and resolution.

The structure of an ACH trace number is straightforward:

• The first eight digits represent the financial institution’s routing number
• The remaining seven digits form a sequential number assigned to that transaction by the originating bank

Businesses rely on ACH trace numbers to maintain visibility and control over their electronic payments.

Components of an ACH trace number

Each ACH transaction generates two trace numbers—one from the originating bank and another from the receiving bank. This dual-tracking system ensures visibility from both ends of the transaction so either party can initiate troubleshooting when needed.

• Originating trace number: Created by the originating depository financial institution (ODFI), this 15-digit number identifies and tracks the transaction as it enters the ACH network
• Receiving trace number: Assigned by the receiving depository financial institution (RDFI), this number helps track the transaction from the receiving end, especially when issues occur on that side of the transfer

Here’s what a typical trace number looks like:

011000012345678

• 01100001 = Routing number (bank identifier)
• 2345678 = Transaction number (unique to this transfer)

Where to find your ACH trace number

You may need to locate an ACH trace number to verify a payment or resolve a delayed payment. These identifiers aren’t always easy to spot, but most banks make them accessible through standard channels.

Common places to find your ACH trace number include:

• Transaction receipts or confirmation emails: Many financial institutions include the trace number in the confirmation message sent after you initiate an ACH transfer
• Bank statements: Monthly statements often list ACH transactions with their trace numbers in the transaction details section
• Online banking portals: In your transaction history, select the ACH transfer to view its detailed information, which often includes the trace number
• Bank mobile apps: Mobile apps usually display transaction details, including trace numbers, when you tap a specific ACH transfer
• Customer service: If you can’t locate the trace number yourself, your bank’s customer service can retrieve it with the transaction date and amount

How ACH routing numbers work

An ACH routing number is a nine-digit code that identifies the bank or credit union processing an ACH transfer.

ACH routing numbers act as your bank’s address, ensuring funds are directed to the right place during electronic transfers. They facilitate transactions by:

• Identifying the bank sending or receiving the funds
• Directing funds through the ACH network
• Automating processing, especially for bulk or recurring transactions

Banks often use different routing numbers for different transaction types. One routing number may apply to ACH transfers such as direct deposit or recurring bill payments, while another is reserved for wire transfers used for large or urgent payments.

Finding your ACH routing number

If you’re unsure of your bank’s ACH routing number, there are a few places to check:

• Paper checks: Look at the bottom left of a paper check. The first nine digits are your bank’s routing number, followed by your specific account number
• Bank statements: Some banks include the ACH routing number on a paper or PDF bank statement
• Online banking portals: Check your online banking portal under “Account Details,” “Direct Deposit Information,” or “Routing Info”

Many banks also offer routing number lookup tools on their websites. Be sure to select the ACH routing number, not the one used for wire transfers. Using the wrong number can delay or cancel a transaction.

Tracking ACH payments and transactions

ACH trace numbers don’t provide consumer-facing tracking like package delivery numbers. However, they’re valuable tools when you work with your bank to resolve payment issues or confirm a transaction’s status.

Follow these steps to track an ACH transfer:

1. Contact your financial institution: Reach out to your bank’s customer service by phone, chat, or in person and have your trace number ready
2. Provide complete information: Share the 15-digit trace number along with the transaction date, amount, and names of both the sending and receiving accounts
3. Request status verification: The representative can use the trace number to locate your transaction within the ACH network and determine its current status
4. Understand rejection reasons: If your payment was rejected or returned, the bank can explain the reason code and advise on corrective steps, such as updating account information or ensuring sufficient funds
5. Discuss resolution options: For delayed transactions, ask about expected processing times or alternative payment methods if urgency is a factor
6. Document your case: Request a reference number for your inquiry and note the name of the representative for follow-up

ACH trace numbers don’t offer real-time visibility but serve as internal references banks use to identify, track, and resolve payment issues efficiently.

ACH processing timeline

The standard processing time for ACH transactions is one to three business days because banks handle these payments in batches rather than in real time.

Weekends and bank holidays don’t count as business days, so keep them in mind when planning payments. Many banks also have daily cutoff times. If you submit a transfer after that cutoff, it won’t be processed until the next business day.

Some banks support same-day ACH payments as long as they’re submitted before the cutoff time. The current limit for an individual same-day ACH payment is $1 million, and these transactions may come with higher fees.

Troubleshooting ACH transaction issues

ACH transactions can be delayed or fail if all requirements aren’t met. Common reasons for delay or failure include:

• Incorrect account or routing number
• Submission after the bank’s cutoff time or on a weekend or holiday
• Insufficient funds
• Manual review for large or unusual transfers

If your payment doesn’t arrive, take these steps to resolve the issue:

1. Review account details: Confirm that the correct account and routing numbers were used for the transaction
2. Request the trace number: Ask the sender for the ACH trace number so you can track the payment
3. Contact your bank: Call your bank with the trace number and transfer date so they can locate it within the ACH network. If necessary, contact the sender’s bank to confirm the payment was initiated

How ACH trace numbers help

ACH trace numbers work much like shipping tracking numbers. Banks use them to determine the status of a transfer within the ACH network, verify whether funds have reached the receiving bank, and identify where any delays or failures occurred. Because only banks have access to the ACH network, you’ll need to contact your bank with the trace number to initiate tracking or resolve payment issues.

Best practices for ACH transfers

ACH transfers are generally reliable, secure, and cost-efficient. Follow these best practices to ensure smooth processing:

• Verify bank details: Before initiating a transaction, confirm routing and account numbers using proper documentation and secure communication
• Standardize payment processes: Build clear internal procedures for ACH transactions to maintain consistency
• Monitor transactions: Review your accounts regularly for unusual or unauthorized activity
• Work with reputable banks: Choose banks or credit unions with strong security and compliance measures
• Use up-to-date software: Keep your banking and accounting software current with the latest security patches and ACH integrations

Security considerations for ACH payments

Because ACH payments involve direct access to sensitive bank information, it’s important to implement strong security measures:

• Authentication: Require multi-factor authentication for initiating ACH transactions
• Encryption: Ensure all sensitive data, such as account numbers, remains encrypted throughout every transaction
• User roles and permissions: Create role-based permissions within ACH systems to limit access to only the team members who need it
• Data storage: Keep bank information in secure databases with controlled access

Tips for businesses using ACH transfers

ACH transfers can make payment processing faster and more consistent for both senders and recipients, but they require ongoing attention to stay effective. Keep these tips in mind when managing your ACH transfers:

1. Set recurring payments: ACH payments are ideal for recurring bills, payroll, or vendor payments because they save time and reduce human error
2. Encourage customers to use ACH: Offer ACH payments in your terms and highlight their lower processing fees
3. Build strong supplier relationships: Communicate directly with suppliers before processing any payments to confirm all details
4. Monitor processing times: The standard ACH timeline is one to three business days, so factor that into your planning and cash flow forecasts
5. Use ACH positive pay services: If available, use ACH positive pay services to verify transactions before they clear and prevent fraud

Record-keeping recommendations

Maintaining accurate records is an essential part of ACH transaction security. It supports reconciliation, audits, and fraud prevention. Keep logs for all ACH transfers, including dates, amounts, vendor information, and approvals, and retain ACH authorization forms for at least two years in case you need to verify a payment.

Review and reconcile ACH activity regularly to catch errors, delays, or failed payments early. Ideally, match your bank statements to ACH transactions on a daily or weekly basis.

Keep records secure by following federal and local data retention rules, and back up your systems frequently so you’re prepared if an audit occurs.

ACH transfer security tips

Keeping ACH transfers secure requires diligence and strong internal controls. Focus on these key practices:

1. Verification procedures: Never initiate an ACH transaction without verifying bank details through a secure, trusted channel, especially when receiving new or updated information. Implement dual authorization so two people approve each transaction, and confirm any changes to payment instructions directly with vendors by phone.
2. Fraud prevention measures: Educate your team to recognize scams and limit ACH permissions to essential staff. Enable real-time alerts to flag unusual or suspicious activity.
3. If you suspect fraudulent activity: Act immediately. Contact your bank or payment processor to block the transaction; there’s only a short window in which a transfer can be reversed. Notify the right internal stakeholders and report the incident to your bank and law enforcement authorities.

Streamline your payment processes with Ramp

ACH trace numbers allow your bank to track transactions within the ACH network and identify if there are problems, so you’re never left in the dark, awaiting payment. Understanding how ACH transactions work helps you stay on top of your cash flow.

But payment management becomes complex as your business grows. While ACH transfers offer vendor payment automation, most platforms fail to integrate them with your full accounts payable operations.

With Ramp Bill Pay, you can:

• Reduce administrative work: Cut invoice processing time through digital approval systems and automatic matching. Ramp's AI capabilities handle the details, boosting efficiency and cutting costs.
• Simplify vendor management: Bring all vendor setup into one place and confirm banking details for reliable payments. Vendors can securely validate their information via a direct link.
• Select flexible payment options: Choose your preferred payment method with Ramp, including ACH, virtual credit cards, checks, or wire transfers
• Save money: Ramp offers domestic bill payments without processing fees

Try Ramp Bill Pay to make payments easier, enhance cash flow visibility, and maintain smooth business operations.

This post includes general information about ACH payments. For help with ACH functionality specific to Ramp, visit Ramp Support for more details.