Real-time vs. Real Time

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Candace Osmond

Candace Osmond studied Advanced Writing & Editing Essentials at MHC. She’s been an International and USA TODAY Bestselling Author for over a decade. And she’s worked as an Editor for several mid-sized publications. Candace has a keen eye for content editing and a high degree of expertise in Fiction.

Real-time, with a hyphen, is an adjective describing something in which results, feedback, or statistical data follow input with no noticeable delay. The word is increasingly spelled realtime, and this may eventually become the standard spelling if people continue to find the adjective useful. For now, though, the hyphenated form is preferred.

What’s the Difference Between Real Time and Real-Time?

Both real time and real-time are used in technology. They go all the way back to the early 19th century when there was a need to reference philosophy and logic. After some time, science and technology started having more dominance over the words.

We often hear the phrase real-time data in computers and technology. It means someone obtains the transmitted data and makes it available instantly. We’re talking about microseconds, something that the older technology could not do. 

But real-time can also be used to describe systems with time constraints. This differs depending on the specific system’s response to input. Mechanics might depend on a system of microseconds, but a new video game might depend on a response time of milliseconds.

However, the difference between the two words lies not only in spelling but also in meaning and parts of speech.

According to Merriam-Webster Dictionary, real time is a noun that means the actual time during which something takes place.

Cambridge Dictionary states that real-time is an adjective that means communicated or presented at the same time as it happens.

It’s understandable why many get confused between the two. They have similar meanings but different styles and placements. When you watch the news, and the reporter is updating on the television, these are real-time updates. Or you can say the reporter is updating in real time.

Statistics on Real Time and Real-Time

Below is a graph of real time’s and real-time’s use throughout the years.

real time vs real time

This information does not imply that the more commonly used term is the correct term. Real time and real-time have different uses despite their similar meanings. The graph only shows the trend in the usage of both words throughout the years. 

The two terms rose in popularity as technology became more advanced. The process of receiving transmitted data without pause is also called “reactive computing” since the program guarantees real-time constraints.

These programs use time simulations to continue running as they mirror what would happen in real life. Video games are an example of programs that run in simulated real time.

What is a Compound Adjective?

A compound adjective is made of two or more adjectives to modify a noun or a pronoun. Like single adjectives, they can also answer questions such as “What kind?” But you can distinguish them from single-word adjectives through the use of hyphens.

If real-time is a compound adjective, does that mean real time is not an adjective anymore? Exactly. If there is no hyphen, it’s not an adjective. Instead, it’s a noun phrase. Or it can be an adverbial phrase if you add the preposition in before it. 

What’s the Point of a Hyphen?

The point of hyphenated compound adjectives is to show that it’s a single adjective. Take the phrase real-time telemedicine for example. Here, hyphens join the words real and time to show that it’s one adjective modifying the noun telemedicine. 

Suppose you say real time telemedicine, the meaning changes. Without the hyphen, the phrase might mean time telemedicine that is real. Real time medicine becomes an open compound noun modified by the adjective real.

How to Know When to Use a Hyphen

Most of the time, you’ll know that a hyphen is needed if there’s a noun after it–for example:

  • Real-time information.
  • Real-time consultation.
  • Real-time noise cancellation. 

But there are also trickier moments where there is no noun before the compound adjective. In this case, you should analyze the sentence. Ask yourself, is real-time supposed to describe a noun or pronoun in this sentence? Here’s an example:

  • The software provides updates that are real-time.

In this sentence, real-time describes the direct object updates. But if this is too complicated for you, just say, “The software provides updates in real time.” It also sounds more appropriate!

Real Time as a Noun Phrase

Real time as a noun phrase means real is an adjective, while time is a noun–for example:

  • We haven’t spent real time together since you came home.

Real time is not a compound adjective because it does not modify any noun. It’s also not an adverbial phrase because it does not describe an action. Instead, it’s the direct object for the verb have spent. It’s a direct object because it answers the question, “Haven’t spent what?” 

The noun phrase usually refers to intimate time (together). It implies that we often spend so much time with other people yet never genuinely bond with them. 

For example, a couple might be living together in one apartment. But they don’t eat meals together or talk to one another. In other words, they don’t spend real time together.

What is an Adverbial Phrase?

An adverbial phrase is made of more than one word that functions as an adverb. An adverb modifies a verb, adjective, clause, or sentence. Real time is not an adverbial phrase, but in real time is. Take a look at this example:

  • I prefer Twitter because the handlers update in real time through threads.

In this sentence, the adverbial phrase in real time describes the verb update.

Examples of Real Time in a Sentence

Millions of New Yorkers will be floored to know that a new HTML5 webapp called will soon track subways in real time. [Gizmodo]

She says it is effective because it involves active problem-solving in real time and students are engaged. [Herald Sun]

Now, Transurban is obliged to adjust the tolls in real time to keep traffic in the express lanes moving at an average minimum speed of 45 mph. [Washington Post]

Examples of Real-Time in a Sentence

Public transit commuters have less interest in real-time digital social interactions with fellow commuters. [New York Times]

Within the next few years, rapid and real-time surveillance of pathogens is expected to become standard practice. [Guardian]

He says that Twitter’s system is engineered for real-time search and distribution, not archive search and distribution. [TechCruch]

Bottom Line

The English language can be confusing, but learning the difference between real time and real-time will enhance your grammar skills. Remember that the hyphenated version is a compound adjective, while the other is a noun phrase. Add in before the phrase, and you’ll get an adverbial expression such as everyday vs. every day