# How is $e^x$ read aloud?

My current research colleague from New Castle told me that I was reading it wrong. I usually read it as e power x.

How do you read aloud $e ^ x$?

Is it:

• e raised to x
• e power x
• e powered x
• or e raised to the power x.

What is the correct pronunciation?

• "$e$ raised to the power $x$" is right, and probably most other locutions are just abbreviations of that one. I don't think any of them are good nomenclature. There's no good way to do it. – Michael Hardy Sep 23 '12 at 16:47
• I've only heard 'e to the x' when that notation is used. $\exp(x)$ would be the exponential of x. – preferred_anon Sep 23 '12 at 17:05
• A related terminological problem is that my students all want to describe $x^2$ as "exponential." Whenever they do this, I immediately write down $2^x$ and tell them that it's only exponential if $x$ is in the exponent; $x^2$ is a power law, not an exponential. But this doesn't seem to sink in too well with my students, and it will probably never penetrate popular culture, since "exponential" sounds catchy and cool. Is there any alternative to "power law" that is catchy and has some hope of entering the zeitgeist? "Monomial" seems about as cool as Grandma's cotton panties. – Ben Crowell Sep 23 '12 at 17:43
• Grammar nazis? In real life? Would never had suspected it. Anyway, I generally avoid talking about math without a pen and paper, or a whiteboard; that way everybody understood even if you mispronounced x + 2 as "eks bi tu". – Lie Ryan Sep 23 '12 at 19:06
• Tell him that it's an E to the X, to the A, to the M, to the P, to the L, to the E, and that he shouldn't be bothered by your rapping wit when you describe math. Honestly though, both will be the same to 99% of people. – gparent Sep 23 '12 at 19:16

I think "e to the x" or "the exponential of x" are both fine. I might even use "e of x."

• "e to the x" is the equivalent used in italian "e alla x" – enzotib Sep 23 '12 at 16:47
• "e-to-the-x" is very common, and is easily enunciated, while some of the other logically-reasonable possibilities are less easily said out loud, I think. – paul garrett Sep 23 '12 at 16:48
• I interpet "e of x" as $e(x)$ – Belgi Sep 23 '12 at 16:48
• So at least for once, German is less verbose than English: "$e$ hoch $x$" :) – Tim Pietzcker Sep 23 '12 at 20:44
• @enzotib: same in Spanish:: "e a la x" – leonbloy Sep 23 '12 at 23:10

When I read it out loud, I prefer saying e to the $\rm x$ because it is a quick phrase and means the same as e raised to the $x$th power. Albeit, it still differs from person-to-person.

I would usually say "e to the x", but when the interpretation is clear "e x" is sufficient to me.

• I never say “ee eks”, and I have never heard anyone say that. – Lubin Sep 24 '12 at 0:15
• Perhaps not in the first explanation of an equation, but if you have to say it many times, that's what I default to. Particularly reading/taking about anything in continuous time finance, $e^{-rT}$ quickly becomes 'ee minus arr tee' for me. – Andrew Christianson Sep 24 '12 at 15:36
• in french "e x" is used quite often. or at least, was, 3~4 years ago when I was on college (on the condition that e is not a variable in this context) – Mathieu Sep 25 '12 at 19:04
• I have too got accustomed to e x. +1 – Sawarnik Mar 14 '14 at 17:36

I always read it as "e to the power of x", which is perhaps a little verbose.

• Same here. I find that this is as succinct as I can be without stepping over the line of ambiguity. It is what I say as a shortening of "e raised to the power of x". – Victor Sep 24 '12 at 11:36

Given that your avatar is the infamous Wolfram|Alpha logo "hombic hexecontahedron", I suppose you're reasonably familiar with Mathematica. If you have Mathematica handy, there is a systematic solution to this type of questions, viz. how to pronounce some mathematical expressions in Engish, using Mathematica's SpokenString[] function. For example,

In:= SpokenString[e^x]

Out= "e to the power of x"


Some more complex expressions such as $\int_0^1 \sin (x) dx$ which is written in Mathematica as Integrate[Sin[x], x, {x, 0, 1}] can evaluate by itself, and hence need to be wrapped with HoldForm and then passed to SpokenString[]:

In:= SpokenString[HoldForm[Integrate[Sin[x], x, {x, 0, 1}]]]

Out= "the integral of sine of x over x from 0 to 1, then with respect to x"

In:= SpokenString[Integrate[Sin[x], x, {x, 0, 1}]]

Out= "x minus x times cosine of 1"


I've heard that this (combined with Speak[]) is used to aid teaching blind and/or deaf people mathematics.

e raised to the power x

is correct and clear

to the students what you mean

• With such line breaks, I / was expecting an artful / haiku, but alas. – NReilingh Sep 24 '12 at 15:08
• I made it a haiku – bobobobo Nov 23 '12 at 19:10

We usually say; e to the power x (e is supposed to be raised and its value will increase )

• I think saying that "its value will increase" is a little misleading. – rschwieb Oct 11 '12 at 19:21

e to the x is what I say. I think that as long as it's understood what you mean, it's OK.

I say, "e to the x." It is simplest.

Since no one else (except the OP) has suggested this: even though mostly I would say "$e$ to the $x$", I often say "$e$ raised to the power $x$".

i think "exponential of $x$" is the correct way but "e to the x" is also used commonly