CSS to make HTML page footer stay at bottom of the page with a minimum height, but not overlap the page

A simple method is to make the body 100% of your page, with a min-height of 100% too. This works fine if the height of your footer does not change.

Give the footer a negative margin-top:

footer {
    clear: both;
    position: relative;
    height: 200px;
    margin-top: -200px;
}

Below are 4 different methods of mine:

In each example the texts are freely-editable to illustrate how the content would render in different scenarios.


1) Flexbox

body{ height:100vh; margin:0; }

header{ min-height:50px; background:lightcyan; }
footer{ min-height:50px; background:PapayaWhip; }

/* Trick */
body{ 
  display:flex; 
  flex-direction:column; 
}

footer{
  margin-top:auto; 
}
<body>
  <header contentEditable>Header</header>
  <article contentEditable>Content</article>
  <footer contentEditable>Footer</footer>
</body>

2) Grid

body{ 
  min-height: 100vh; 
  margin: 0; 
  
  display: grid;
  grid-template-rows: auto 1fr auto;
}

header{ 
  min-height:50px;
  background:lightcyan; 
}

footer{ 
  min-height:50px; 
  background:PapayaWhip; 
}
<body>
  <header contentEditable>Header</header>
  <article contentEditable>Content</article>
  <footer contentEditable>Footer</footer>
</body>

This method below uses a "trick" by placing an ::after pseudo-element on the body, and set it to have the exact height of the footer, so it will occupy the exact same space the footer does, so when the footer is absolute positioned over it, it would appear like the footer is really taking up space and eliminate the negative affects of it's absolute positioning (for example, going over the body's content)

3) position:absolute (no dynamic footer height)

body{ min-height:100vh; margin:0; position:relative; }
header{ min-height:50px; background:lightcyan; }
footer{ background:PapayaWhip; }

/* Trick: */
body {
  position: relative;
}

body::after {
  content: '';
  display: block;
  height: 50px; /* Set same as footer's height */
}

footer {
  position: absolute;
  bottom: 0;
  width: 100%;
  height: 50px;
}
<body>
  <header contentEditable>Header</header>
  <article contentEditable>Content</article>
  <footer contentEditable>Footer</footer>
</body>

4) Table-layout

html{ height:100%; }
body { min-height:100%;  margin:0; }

header {
  height: 50px;
  background: lightcyan;
}

article { 
  height: 1%;
}

footer {
  height: 50px;
  background: PapayaWhip;
}

/**** Trick: ****/

body {
  display: table;
  width: 100%; 
}

body > footer {
   display: table-row;
}
<body>
  <header contentEditable>Header</header>
  <article contentEditable>Content</article>
  <footer contentEditable>Footer</footer>
</body>

A very simple approach which works great cross browser is this:

http://matthewjamestaylor.com/blog/keeping-footers-at-the-bottom-of-the-page

html,
body {
   margin:0;
   padding:0;
   height:100%;
}
#container {
   min-height:100%;
   position:relative;
}
#header {
   background:#ff0;
   padding:10px;
}
#body {
   padding:10px;
   padding-bottom:60px;   /* Height of the footer */
}
#footer {
   position:absolute;
   bottom:0;
   width:100%;
   height:60px;   /* Height of the footer */
   background:#6cf;
}
<div id="container">
   <div id="header">header</div>
   <div id="body">body</div>
   <div id="footer">footer</div>
</div>