Comparing Real-Time Payments vs Same-Day ACH

Key takeaways:

• Same‑Day ACH reduces processing time from days to hours, giving businesses a reliable way to move funds within the same business day.
• Instant payments offer immediate, final settlement 24/7/365, which helps companies manage cash flow with greater precision.
• Both payment types continue to grow because they support digital demand and improve efficiency across the payment value chain.
• Same‑Day ACH is well‑suited for payroll, routine payables and high‑volume transactions that benefit from predictable timing and broad availability.
• Instant payments best support urgent use cases that depend on immediate availability of funds.

Payment systems driven by digital demand

The U.S. payments system has transformed over the past decade. When same-day settlement was introduced in 2016, it was seen to dramatically improve payroll, bill payments and person-to-person transactions. For businesses, these digital transactions have helped increase efficiency across the payment value chain, in particular by reducing reliance on cumbersome, manual paper check processing, improving liquidity, boosting efficiency, lowering costs and helping prevent fraud.

These positive changes left consumers and businesses clamoring for even speedier digital transactions, and along came more options.

The history of Same-Day ACH: A phased approach with big business benefits

In order to facilitate same-day funds settlement in the ACH payment network, the National Automated Clearing House Association (NACHA) introduced the first phase of new rules in late 2016. As a result, instead of ACH settlement times running one to two days, the option of settling funds within 24 hours was made available. A “same-day fee” was included with each new Same-Day ACH transaction to cover the costs associated with the faster settlement process. The second phase, which began in September 2017, made Same-Day ACH available for debit entries, enabling faster processing of virtually any ACH payment. The final phase, which started in March 2018, required that receiving depository financial institutions make bank credit funds available from Same-Day ACH credits to depositors on the same day.

The development of Same-Day ACH required some corporates to adjust their infrastructure to accommodate same-day processing. But these changes opened the door to new market opportunities, efficiencies and cost-savings and ultimately allowed more information to be communicated more securely, with the end result of reducing fraud.

Despite the recent explosion of RTP adoption, Same-Day ACH continues to grow steadily, providing a reliable payment option that’s especially popular for business payments, according to Nacha, the regulatory body for the automated clearing house network.

The launch of Real-Time Payments

In 2017, The Clearing House launched the Real-Time Payments (RTP) network, introducing 24/7/365 instant, final settlement in the United States. For the first time, businesses could send and receive funds within seconds, with immediate availability and irrevocable confirmation. This shift significantly enhanced cash flow management, liquidity control and many other benefits.

Today, instant payments have become a competitive necessity. Yet confusion remains about how they differ from Same-Day ACH, which settles within hours during banking windows. Understanding the history and core distinctions between these two payment types helps clarify when and why each should be used.

The road to instant payments: Setting the new U.S. standards

The Federal Reserve Bank (Fed) noticed how business payees in the U.S. showed a strong preference for instant or one-hour payments. As a result of these market demands, and in an effort to catch up to the rest of the world’s RTP adoption, the Fed formed a task force in May 2015 of over 300 representatives from financial institutions, government, consumer interest organizations, non-bank providers, regulators, technology solution providers and trade groups to set new standards for how payments should be modernized in this country.

This task force, which Fifth Third Bank served on, concluded in July 2017, after successfully developing specific standards to make instant payments a reality in the U.S. It put rules in place that allowed funds availability to recipients within 30 minutes any time of the day or night and allowed senders to initiate payments based on minimal information about the recipient, such as name or email address. With these new standards, the U.S. continued to adopt faster payments and harmonize with the rest of the world.

Six years later, in July 2023, the Fed launched their own instant payments system, FedNow, that allows people and businesses across many industries to move money immediately, any time of day, every day of the year. It was another big leap forward for the U.S. in adopting instant payment processing.

Today, enterprises in around 80 countries offer RTP to suppliers, customers and consumers. In the U.S., the Clearing House’s Real-Time Payments completed 125 million transactions amounting to $405 billion in Q4 2025 alone.

Two growing payment types serving distinct business needs

The differences in speed, cost, operating hours and technical capabilities between RTP and Same-Day ACH mean that they each fill unique roles in the U.S. payments ecosystem.

Same‑Day ACH offers predictable, same-day settlement during banking hours, making it ideal for payroll, bill payments and high-volume transactions that benefit from cost efficiency and broad bank coverage. Instant payments deliver instant movement of funds at any time of day, which supports urgent disbursements, time-sensitive bill payments and improved customer experiences.

Why payment choice now matters more than ever

As the adoption of faster payments continues to accelerate amongst businesses and consumers alike, the conversation has shifted from whether businesses can move money faster to how and when they should. With multiple payment rails now available, organizations must navigate the tradeoffs between immediacy, cost, operational flexibility and network reach. What once felt like a linear evolution toward speed has become a more nuanced payment landscape.

Same-Day ACH and instant payments both play important roles in meeting today’s business expectations for faster funds availability, but they are not interchangeable. Each was built on different infrastructure, carries different operating considerations and supports distinct business use cases. Understanding those differences allows companies to deploy each payment type more intentionally.

Fifth Third is committed to ensuring that our corporate clients are ideally positioned to take full advantage of the many business opportunities the modernized payment system presents, such enhanced cash flow forecasting, improved working capital and same-day payroll. To learn more, find a business banker.