Position Footer At Bottom of Page Having Fixed Header

Position footer at bottom of page having fixed header

As you have mentioned, position: fixed would position the footer with the respect to the viewport rather than the page itself. Therefore, we have to keep the element in normal flow and somehow position it to the bottom of the page.

There are couple of approaches to achieve that, which have been discussed in the wild during the time.

For instance:

A List Apart's article Exploring Footers - by Bobby Van Der Sluis, 2004
footerStickAlt - by Craig Erskine, 2005
Sticky Footer - by Shelly Cole, 2006
How to keep footers at the bottom of the page - by Matthew James Taylor, 2007
Make the Footer Stick to the Bottom of a Page - by Ryan Fait, 2007
Refined version of Ryan Fait's Sticky Footer - by Chris Coyier, 2009
Sticky CSS footers: The flexible way (which uses CSS Tables) - by Torben Haase, 2011
Responsive Sticky Footer (refined version of Torben's approach) - by Joshua Cook, 2013
Solved by Flexbox's Sticky Footer - by Philip Walton, 2013

Sticky Footer

In this answer I'd go with Ryan Fait's method since it is simple and easy to understand and also it meets your needs (Situations where both header and footer have fixed heights).

Considering the structure below:

<div id="content"> <!-- content goes here. It may (not) include the header --> </div>
<div id="footer">Footer</div>

The following steps are needed:

Setting height of the <html> and <body> elements to 100% which is required for the next step¹.
The most important thing we need to do is to make sure that the #content is high enough to push the #footer down the page. Hence we give the #content a min-height of 100%.
So far, the #content has taken 100% of height of the viewport, thus we should pull the footer up to position it at the bottom of the page. In order to do that we could give the #content a negative margin-bottom equivalent to the footer's height. Also to make sure that the footer appears on top of the content, we should position the footer relatively. Demo Here.
As can be seen, when the #content grows by its contents, some of the contents go behind the footer. We could avoid that either by appending a spacer element at the end of #content or use the combination of padding-bottom and box-sizing: border-box² which is supposed to be supported on IE8 as well.

4.1 Adding a spacer

Example Here

<div id="content">
    <!-- content goes here -->
    <div class="spacer"></div>
</div>
<div id="footer">Footer</div>

.spacer, #footer { height: 100px; }

4.2 Combination of `padding-bottom` and `box-sizing`

Updated Example

#content {
    min-height: 100%;
    margin-bottom: -100px; /* Equivalent to footer's height */
    padding-bottom: 100px; /* Equivalent to footer's height */

    box-sizing: border-box;
}

(Note that vendor prefixes omitted due to brevity)

Adding the Header

If the header should remain in normal flow, you could simply add it to the #content as follows:

(Example Here)
```
<div id="content">
    <div id="header">Header</div>
    ...
```
But if it should be positioned absolutely³, we need to push the contents of #content element down in order to prevent overlapping.

Therefore, again, we could either add a spacer at the beginning of #content (Example Here):

<div id="header">Header</div>
<div id="content">
    <div class="header-spacer"></div> 
    <!-- content goes here -->
    <div class="footer-spacer"></div> 
</div>
<div id="footer">Footer</div>

Or use the combination of padding-top and box-sizing as follows:

<div id="header">Header</div>
<div id="content"> <!-- content goes here. --> </div>
<div id="footer">Footer</div>

#content {
    min-height: 100%;
    margin-bottom: -100px; /* Equivalent to footer's height */

    padding-top   : 50px;  /* Equivalent to header's height */
    padding-bottom: 100px; /* Equivalent to footer's height */

    box-sizing: border-box;
}

Updated Example (Note that vendor prefixes omitted due to brevity)

At last but not least!

Nowadays, All major modern web browsers support box-sizing: border-box declaration (including IE8). However if you're looking for the traditional way which has a wider browser support, stick with using spacer elements.

^{1. This is needed to make min-height: 100% to work on the #content element (because a percentage value is relative to the height of the box's containing block which is established by the <body>). Also <html> should have an explicit height to make height: 100% to work on <body>.}

^{2. box-sizing: border-box makes UAs calculate the width/height of the box including padding and borders.}

^{3. According to spec, absolutely positioned elements are elements having a position of absolute or fixed.}

Fixed header needs to stay at top, fixed footer needs to stay at bottom, remaining amount of space fills main div with content

Different Header And Footer Styles

There are four different code snippets in this answer, each of which demonstrate different Header and Footer behavior as listed below:

Sticky Header & Sticky Footer
Sticky Header & Fixed Footer
Fixed Header & Sticky Footer
Fixed Header & Fixed Footer

You can click on the cards to delete them, so that you can see the behavior when there are less cards. You can also visualize this by toggling the window width.

Sticky Header & Sticky Footer

const nav = document.querySelector("nav");
const footer = document.querySelector("footer");

const container = document.querySelector(".card-container");

for (let i = 0; i < 20; i++) {
    const card = document.createElement("div");
    card.className = "card";
    card.innerText = "Click Me!!";
    container.appendChild(card);
}

const cards = document.querySelectorAll(".card");

cards.forEach((card) => {
    card.addEventListener("click", () => {
        card.style.display = "none";
    });
});

body {
    margin: 0;
    min-height: 100vh;
    display: flex;
    flex-direction: column;

    color: whitesmoke;
    font-family: cursive;
}

header {
    position: fixed;
    top: 0;
    /*Expanding to take full width*/
    right: 0;
    left: 0;
}

footer {
    position: fixed;
    bottom: 0;
    /*Expanding to take full width*/
    right: 0;
    left: 0;
}

header,
footer {
    background: slateblue;
    padding: 1em;
}

.card-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, 150px);
    place-content: center;
    gap: 10px;
    padding: 5em 1em; /* Top Padding Is Required */
}

.card {
    display: grid;
    place-items: center;
    width: 100%;
    height: 100px;
    background: coral;
    border-radius: 5px;
    cursor: pointer;
}

<header>Sticky Header & Sticky Footer</header>
<div class="card-container"></div>
<footer>Sticky Footer</footer>

Have a footer that sit on the bottom of the page with a fixed header

As default model is content-box adding a padding-top to an element with height:100%; will make its height 100% + 130px.

So you have to add another <div> wrapper with auto height and add it padding-top: 130px;

<html style="height:100%;">
<body style="height:100%; margin:0; position:relative;">
    <div id="wrapper" style="min-height:100%;">
        <div id="container" style="padding-top:130px; padding-bottom:130px;">
        </div>
    </div>
    <div id="footer" style="position:absolute; bottom:0; height:130px;">
    </div>
</body>
</html>

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;
}

How do you get the footer to stay at the bottom of a Web page?

To get a sticky footer:

Have a <div> with class="wrapper" for your content.
Right before the closing </div> of the wrapper place the
<div class="push"></div>.
Right after the closing </div> of the wrapper place the
<div class="footer"></div>.

* {
    margin: 0;
}
html, body {
    height: 100%;
}
.wrapper {
    min-height: 100%;
    height: auto !important;
    height: 100%;
    margin: 0 auto -142px; /* the bottom margin is the negative value of the footer's height */
}
.footer, .push {
    height: 142px; /* .push must be the same height as .footer */
}

Position Footer At Bottom of Page Having Fixed Header