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. Sep 23, 2012 at 16:47
• I've only heard 'e to the x' when that notation is used. $\exp(x)$ would be the exponential of x. Sep 23, 2012 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.
– user13618
Sep 23, 2012 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". Sep 23, 2012 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. Sep 23, 2012 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" Sep 23, 2012 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. Sep 23, 2012 at 16:48
• I interpet "e of x" as $e(x)$ Sep 23, 2012 at 16:48
• So at least for once, German is less verbose than English: "$e$ hoch $x$" :) Sep 23, 2012 at 20:44
• @enzotib: same in Spanish:: "e a la x" Sep 23, 2012 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. Sep 24, 2012 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. Sep 24, 2012 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) Sep 25, 2012 at 19:04
• I have too got accustomed to e x. +1 Mar 14, 2014 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". Sep 24, 2012 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[19]:= SpokenString[e^x]

Out[19]= "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[21]:= SpokenString[HoldForm[Integrate[Sin[x], x, {x, 0, 1}]]]

Out[21]= "the integral of sine of x over x from 0 to 1, then with respect to x"

In[22]:= SpokenString[Integrate[Sin[x], x, {x, 0, 1}]]

Out[22]= "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.

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. Oct 11, 2012 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.

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. Sep 24, 2012 at 15:08
• I made it a haiku Nov 23, 2012 at 19:10

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