Vertically center rotated text with CSS

I have the following HTML:

<div class="outer">
    <div class="inner rotate">Centered?</div>
</div>

div.outer is a narrow vertical strip. div.inner is rotated 90 degrees. I would like the text "Centered?" to appear centered in its container div. I do not know the size of either div in advance.

This comes close: http://jsfiddle.net/CCMyf/2/. You can see from the jsfiddle that the text is vertically centered before the transform: rotate(-90deg) style is applied, but is somewhat offset after. This is particularly noticeable when div.outer is short.

Is it possible to center this text vertically without knowing any of the sizes in advance? I haven't found any values of transform-origin that solve this problem.

The key is to set position top and left to 50% and then transformX and transformY to -50%.

.inner {
    position: absolute;
    top: 50%;
    left: 50%;
}

.rotate {  
    transform:  translateX(-50%) translateY(-50%) rotate(-90deg);
}

see: http://jsfiddle.net/CCMyf/79/

It may be a bit late for answering that question, but I stumbled on the same issue and found some way of achieving it, by adding another div in the way.

<div class="outer">
    <div class='middle'><span class="inner rotate">Centered?</span></div>
</div>

and applying a text-align: center on that middle element, along with some positioning stuff:

.middle {
    margin-left: -200px;
    width: 400px;
    text-align: center;
    position: relative;
    left: 7px;
    top: 50%;
    line-height: 37px;
}

The .inner also gets a display: inline-block; to enable both rotate and text-align properties.

Here is the corresponding fiddle : http://jsfiddle.net/CCMyf/47/

The another option to rotate text 90 degree and center on axis Y is:

.rotate-centered {
    top: 50%;
    right: 50%;
    position: absolute;
    transform: scale(-1) translate(-50%, 50%);
    writing-mode: vertical-lr;
 }

<span class="rotate-centered">Text<span>

Example: https://codepen.io/wwwebman/pen/KKwqErL

But because of bad support in IE/EDGE writing-mode does NOT work there: https://developer.mozilla.org/en-US/docs/Web/CSS/writing-mode

Can you add margin: 0 auto; to your "rotate" class to center the text.

.rotate {
  -webkit-transform: rotate(-90deg);
  -ff-transform: rotate(-90deg);
  transform: rotate(-90deg);
  width: 16px;  /* transform: rotate() does not rotate the bounding box. */
  margin: 0 auto;
}

The answer from 'bjnsn' is good but not perfect as it fails when the text contains space in it. For example he used 'Centered?' as text but if we changed the text to let suppose 'Centered? or not' then it will not work fine and will take the next line after space. Ther is not width or height defined for the inner div block.

.inner {
  font-size: 13px;
  font-color: #878787;
  position: absolute;
  top: 50%;
  left: 50%;
  background: #DDD;
}

https://jsfiddle.net/touqeer_shakeel/f1gfy1yy/ But we can make the whole text centered align properly, by setting the inner div width equal to height of the outer div, line-height of inner div equal to the width of the outer div and setting the display flex property for inner div with align-items:center and justify-content:center properties.

.inner {
  font-size: 13px;
  font-color: #878787;
  position: absolute;
  top: 50%;
  left: 50%;
  display: flex;
  justify-content:center;
  align-items:center;
  line-height:40px;
}
$('#height').on('change', function(e) {
  $('.outer').css('height', $('#height').val() + 'px');
  $('.inner').css('width', $('#height').val() + 'px');
});

updated fiddle https://jsfiddle.net/touqeer_shakeel/cjL21of5/

Removing : margin-top: -7px; from .inner made the vertically rotated text centered for me. It also made the horizontal text not centered.

Just remove the above code?

You could add this:

$('.inner').css('margin-top', $(this).parent().height() - 2*$(this).height());

To your .on('change') function, as you can see here: http://jsfiddle.net/darkajax/hVhbp/