<sup>: The SUP Element
Last updated: 2026-10-13
<sup>The SUP Element
Defines superscript text shown above the baseline, used for footnotes (e.g. x²) and ordinals.
| Category | Formatting |
|---|---|
| Content Model | Phrasing content |
| Allowed Parents | Any element that accepts phrasing content |
| Content Tag | Yes — requires closing </sup> tag |
| Status | Standard |
📝 Syntax
<sup>superscript</sup>▶ Example
Edit the code below and see the live result in the playground:
🌐 Browser Support
| Browser |  Chrome |
 Edge |
 Firefox |
 Safari |
 Opera |
|---|---|---|---|---|---|
| <sup> | ✓ v1 | ✓ v12 | ✓ v1 | ✓ v1 | ✓ v1 |
| Supported in all major browsers | |||||
Tip： Superscript is ideal for footnote numbers; pair with <a> to make clickable annotations.
❓ FAQ
QWhat are typical use cases for sup?
AFootnote reference numbers (¹ written as
<sup>1</sup>), math exponents (2ⁿ), and ordinal suffixes (the st in 1st). Text displays above the baseline in a smaller size, the opposite of <sub>.QCan sup and sub be used together?
AThey can be used at different positions, but one character cannot be both a superscript and a subscript — HTML has no stacked notation. For stacking (nuclear notation in chemistry), position two elements manually with CSS
position: relative.QHow do I stop sup from affecting line height?
ASame as
<sub>: the raised superscript can expand the line box. Set line-height: 0 on <sup>, or simulate it manually with vertical-align: baseline plus position: relative; top: -0.5em; font-size: 75% to keep line spacing stable.🏷️ Related Tags
💡 Related Cases
📚 Related Tutorials
