Difference between position:sticky and position:fixed?

html

responsive-design

css-positioning

sticky-vs-fixed

byAnton Shumikhin·Feb 5, 2025

position:sticky transitions an element from position:relative to position:fixed as the viewport hits a certain scroll threshold. This is perfect for sticky headers that need to cling onto the viewport as it scrolls.

Example:

header {
  position: sticky;
  top: 0; /* Like clingy ex, sticks at viewport top */
}

position:fixed, however, detaches the element entirely from the document flow, making it blissfully ignorant of any scrolling activity. This is best suited for static elements like persistent navigational bars.

Example:

.navbar {
  position: fixed;
  bottom: 0; /* Like a loyal dog, stays at viewport bottom */
}

Key contrasts:

Sticky: Follows you around, then decides to stick.
Fixed: Never budges, not bothered by the scroll.

Detailed examination

Differences in Document Flow

An element with position:fixed is obliterated from the document flow, so it leaves no traces within the page layout. A position:sticky element, on the other hand, maintains its layout space as it scrolls with the document until its sticking point.

Parent-Child relationship

A position:sticky element needs a clear offset (top, right, bottom, or left) defined and a scroll-friendly ancestor to maintain its sticky characteristics. In contrast, the position:fixed element treats the viewport as its parent.

Z-index considerations

Both sticky and fixed elements can utilize the z-index to slip over or under other content. However, a sticky element's z-ordered layering only commences when it becomes 'fixed'.

Cross-Browser Compatibility

Make sure to test across various browsers as position:sticky joined the CSS positioning party a tad later compared to position:fixed and might not behave consistently on older or non-mainstream browsers.

Practical Scenarios & Troubleshooting

Practical applications

Navigational menus: ‘Fixed’ for globally accessible navigation, ‘Sticky’ for context-specific navigation.
UI elements (chat boxes, utility panels): ‘Fixed’ for omnipresent user tools, ‘Sticky’ for context-aware guides.

Edge cases & Troubleshooting

Table headers: 'Sticky' would suit table headers for visibility amid vertical scrolling.
Overlapping elements: Mindful layering management is necessary when stacking elements with z-index.
CSS interactions: Applying properties like transform, perspective, or filter can cause unexpected behavior with your positioning.