height: calc(100%) not working correctly in CSS - css

Question

I have a div that I want to fill the whole height of the body less a set number in pixels. But I can't get height: calc(100% - 50px) to work.
The reason I want to do this is I have elements that have dynamic heights based on some varying criteria, e.g. height of the header changes based on different elements it can contain. A content div then needs to stretch to fill the rest of the available space available.
The div element, however, stays the height of the content - it doesn't seem as if it interprets 100% to be the height of the body element.
body {
background: blue;
height: 100%;
}
header {
background: red;
height: 20px;
width: 100%;
}
h1 {
font-size: 1.2em;
margin: 0;
padding: 0;
height: 30px;
font-weight: bold;
background: yellow;
}
#theCalcDiv {
background: green;
height: calc(100% - (20px + 30px));
display: block;
}
<header>Some nav stuff here</header>
<h1>This is the heading</h1>
<div id="theCalcDiv">This blocks needs to have a CSS calc() height of 100% - the height of the other elements.</div>
I would appreciate any help or pointers in the right direction.

Answer 1

You need to ensure the html and body are set to 100% and also be sure to add vendor prefixes for calc, so -moz-calc, -webkit-calc.
Following CSS works:
html,body {
background: blue;
height:100%;
padding:0;
margin:0;
}
header {
background: red;
height: 20px;
width:100%
}
h1 {
font-size:1.2em;
margin:0;
padding:0;
height: 30px;
font-weight: bold;
background:yellow
}
#theCalcDiv {
background:green;
height: -moz-calc(100% - (20px + 30px));
height: -webkit-calc(100% - (20px + 30px));
height: calc(100% - (20px + 30px));
display:block
}
I also set your margin/padding to 0 on html and body, otherwise there would be a scrollbar when this is added on.
Here's an updated fiddle
http://jsfiddle.net/UF3mb/10/
Browser support is:
IE9+, Firefox 16+ and with vendor prefix Firefox 4+, Chrome 19+, Safari 6+

Answer 2

I was searching why % doesn't seem to work. So, I tested out using 100vh instead of just setting it at 100% it seems that 100vh works really well across almost all browsers/devices.
example: you want to only display the top div to the user before it scrolls, like a hero banner module. But, at the top of the page is a navbar which is 68px in height. The following doesn't work for me at all doing just %
height: calc(100% - 68px);
There's was no change. The page just stayed the same. However, when swapping this to "vh" instead it works great! The div block you assign it too will stay on the viewer's device hight only. Until they decide to scroll down the page.
height: calc(100vh - 68px);
Change the +/- to include how big your header is on the top.
If your navbar is say 120px in height then change 68px to 120px.
Hope this helps anyone who cannot get this working with using normal height: calc();

Answer 3

First off - check with Firebug(or what ever your preference is) whether the css property is being interpreted by the browser. Sometimes the tool used will give you the problem right there, so no more hunting.
Second off - check compatibility: http://caniuse.com/#feat=calc
And third - I ran into some problems a few hours ago and just resolved it. It's the smallest thing but it kept me busy for 30 minutes.
Here's how my CSS looked
#someElement {
height:calc(100%-100px);
height:-moz-calc(100%-100px);
height:-webkit-calc(100%-100px);
}
Looks right doesn't it?
WRONG
Here's how it should look:
#someElement {
height:calc(100% - 100px);
height:-moz-calc(100% - 100px);
height:-webkit-calc(100% - 100px);
}
Looks the same right?
Notice the spaces!!!
Checked android browser, Firefox for android, Chrome for android, Chrome and Firefox for Windows and Internet Explorer 11. All of them ignored the CSS if there were no spaces.
Hope this helps someone.

Answer 4

try setting both html and body to height 100%;
html, body {background: blue; height:100%;}

Answer 5

All the parent elements in the hierarchy should have height 100%. Just give max-height:100% to the element and max-height:calc(100% - 90px) to the immediate parent element.
It worked for me on IE also.
html,
body {
height: 100%
}
parent-element {
max-height: calc(100% - 90px);
}
element {
height:100%;
}
The Rendering in IE fails due to failure of Calc when the window is resized or data loaded in DOM. But this method mentioned above worked for me even in IE.

Answer 6

You don't need to calculate anything, and probably shouldn't:
<!DOCTYPE html>
<head>
<style type="text/css">
body {background: blue; height:100%;}
header {background: red; height: 20px; width:100%}
h1 {font-size:1.2em; margin:0; padding:0;
height: 30px; font-weight: bold; background:yellow}
.theCalcDiv {background-color:green; padding-bottom: 100%}
</style>
</head>
<body>
<header>Some nav stuff here</header>
<h1>This is the heading</h1>
<div class="theCalcDiv">This blocks needs to have a CSS calc() height of 100% - the height of the other elements.
</div>
I stuck it all together for brevity.

Answer 7

If you are styling calc in a GWT project, its parser might not parse calc for you as it did not for me... the solution is to wrap it in a css literal like this:
height: literal("-moz-calc(100% - (20px + 30px))");
height: literal("-webkit-calc(100% - (20px + 30px))");
height: literal("calc(100% - (20px + 30px))");