RMS Meaning: Here’s What It Means and How to Use It

Your writing, at its best

Compose bold, clear, mistake-free, writing with Grammarly's AI-powered writing assistant

If you’re a math whiz or particularly fond of chemistry, you’re likely familiar with the acronym RMS, but do you know what it means?

This guide explores RMS to uncover what this acronym stands for, its meaning, proper usage, and more. So if you’ve ever wondered about the definition behind RMS — keep reading.  

What Is the Definition of RMS?

According to the Brittanica Dictionary, the abbreviation RMS stands for Root-Mean-Square and refers to the square root of the mean squares of all instantaneous values of an AC signal. 

Denoted by “Vrms” or “Irms,” RMS (AKA quadratic mean) voltage can also be defined for continuously varying voltage (or current) in terms of an integral of the squares of the instantaneous values during a cycle.

For alternating electric voltage, RMS is equal to the value of the constant direct current that would produce the same average power dissipation in a resistive load. 

We should also note that in estimation theory (a branch of statistics that deals with estimating the values of parameters based on measured empirical data that has a random component), the RMS deviation of an estimator is a measure of the imperfection of the fit of the estimator to the data.

So, what does RMS mean, you ask?

In short, root-mean-square is the effective value of alternating current or voltage. The RMS of a group of numbers is the square of the arithmetic mean, which defines the continuous waveform. 

In other words, the root mean square is the magnitude of a set of numbers. 

What Is RMS Used For?

The RMS formula is very useful in many various fields, but it’s most common in electrical engineering and the domain of signal amplifiers. RMS proves to be very useful when the random variables in the data are both positive and negative. 

How Is RMS Calculated?

The RMS formula can be a little challenging to grasp, but it essentially calculates the equivalent direct current value of an alternating current waveform. In technical terms, it determines an alternating current wave shape’s “effective” or direct current heating value. 

To discover a number set’s RMS, square all the numbers in the data set before finding the arithmetic mean of the squares. Take the square root of your answer, and voila — you’ve identified the root mean square. 

What Are the Other Meanings of RMS?

Although RMS is widely known as root mean square, the abbreviation does have a few other meanings:

  • RMS Carpathia 
  • Railway Mail Service
  • Redwood Middle School — U.S. California
  • RMS Olympic
  • Retail Management System
  • Royal Mail Service 
  • Rhabdomyosarcoma
  • Risk Management Strategy
  • Remote Monitoring System
  • Royal Mail Ship
  • Restaurant Management System — Point of Sale or POS
  • RMS Titanic
  • Reliability, Maintainability and Safety 
  • Resource Management System
  • Rights Management Services — a 2003 Microsoft Windows Server

What Are Translations of Root Mean Square?

When used in the English language, most people know our word of the day as “RMS,” but did you know that it looks different in other parts of the world? Yup, it’s true — here are some common translations of root-mean-square:

  • Afrikaans — wortel gemiddelde vierkant
  • Arabic — الجذر يعني مربع
  • Bulgarian — корен среден квадрат
  • Chinese (simplified) — 均方根
  • Finnish — juuren keskimääräinen neliö
  • French — racine moyenne carrée
  • German — Wurzel mittleres Quadrat
  • Spanish — raíz cuadrática media
  • Swedish — rot betyder kvadrat
  • Thai — รากหมายถึงสี่เหลี่ยมจัตุรัส
  • Turkish — kök ortalama kare
  • Ukrainian — середній квадрат кореня
  • Vietnamese — căn bậc hai trung bình
  • Greek — ρίζα μέσο τετράγωνο
  • Italian — radice media quadrata
  • Dutch — wortelgemiddeld kwadraat
  • Danish — rod middel kvadrat
  • Japanese — 二乗平均平方根
  • Korean — 루트 평균 제곱
  • Norwegian — gjennomsnittlig rot firkantet
  • Polish — średni pierwiastek kwadratowy
  • Portuguese — raiz quadrado média
  • Russian — среднеквадратический корень
  • Croatian — korijenski srednji kvadrat
  • Czech — odmocnina střední čtverce

Related Terms You Should Know

Understanding RMS can be a little confusing — especially if you’re unfamiliar with the jargon. Not to worry, though; we compiled a short list of related terms for you to study below:

  • Volts — the Standard International (SI) unit of electric potential or electromotive force
  • Electric Current — a stream of altered particles, such as ions or electrons, moving through an electrical conductor or space
  • Amplifier (amp) — an electric device that boosts the current, voltage, or power of a signal
  • OHMS — the SI-derived unit of electrical resistance, named after German physicist Georg Ohm
  • Peak value — the maximum value reached by an alternating quantity in one cycle
  • Resistor — a passive two-terminal electrical component that implements electrical resistance as a circuit element
  • Sine wave — a curve representing periodic oscillations of constant amplitude as given by a sine function
  • True RMS — a device that can measure alternating current or voltage
  • Subwoofer — a loudspeaker designed to reproduce low-pitched audio frequencies
  • Wattage — a measure of electrical power expressed in watts
  • RMS value (aka the effective or heating value of AC) — the square root of the average value of the squared function of the instantaneous values
  • Parseval’s theorem (aka Rayleigh’s theorem or energy theorem) — a theorem that expresses the energy of a signal in the time-domain in terms of the average energy in its frequency components


RMS stands for Root-Mean-Square and is used commonly in mathematics and its applications. Also known as quadratic mean, RMS is defined as the square root of the mean square. In other words, it’s a statistical function for finding the average of a series.  

Now that you understand the meaning behind RMS, we invite you to explore our website where you’ll discover informative blogs, useful tips, and great grammar tools. 

Whether you’re looking for an explanation on a new trendy word or simply hoping to enhance your existing vocabulary, you can always count on The Word Counter to have your back!


root-mean-square voltage | electronics | Britannica

RMS Voltage of a Sinusoidal AC Waveform | Electronics Tutorials

Explaining rms voltage and current | IOPSpark