font inspectorWhat font does Stack Overflow use?
Stack Overflow serves millions of pages a day and keeps them light: its Stacks design system asks the operating system for a font instead of downloading one. We inspected the logged-out question list that stackoverflow.com redirects to.
Short answer: Stack Overflow uses no web font at all. Text is set in the system font stack, so you see Segoe UI on Windows, San Francisco on a Mac and Roboto on Android, with the system monospace font for code.
System font stack
System font98.9%- CSS name
-apple-system- Weights
- 400, 500, 700
- Sizes
- 17px · 13.1px · 13px · 12px · 11px
System monospace
System font1.1%- CSS name
ui-monospace- Weights
- 400
- Sizes
- 11px
Sizes, weights and spacing by role
These are computed values from the live page, which is what the Font Inspector panel shows when you click each element.
| Role | Font | Size | Weight | Line height | Letter spacing |
|---|---|---|---|---|---|
| Headline | System font stack | 27px | 400 | 1.3 | normal |
| Subheading | System font stack | 19px | 400 | 1.31 | normal |
| Body text | System font stack | 13px | 400 | 1.31 | normal |
| Navigation | System font stack | 13px | 400 | 1.31 | normal |
The main font stack in the CSS:
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI Adjusted", "Segoe UI", "Liberation Sans", sans-serif;- Body text is 13px, small by today’s standards, with a line height of about 1.31. Question titles are 17px.
Segoe UI Adjustedis a local alias declared with@font-faceand adjusted metrics, so Windows text sits closer to how San Francisco sits on a Mac.- Headlines are regular weight, 400. The page relies on size and color rather than bold for hierarchy.
Check any site yourself in one click.
Sites change their type without notice. Font Inspector shows the rendered font, size, weight and spacing of any text on stackoverflow.com or anywhere else, and lists every font on the page. Free, no account.
About the fonts, and whether you can use them
System font stack
The stack starts with -apple-system and BlinkMacSystemFont for San Francisco on Apple devices, then Segoe UI for Windows and Liberation Sans for Linux. On our Windows machine it rendered as Segoe UI.
Can you use it? Free to use: name the system fonts in your CSS and each device supplies its own. Nothing to license or download.
System monospace
Code and tags use ui-monospace, which resolves to the system’s own monospace font, SF Mono on a Mac.
Can you use it? Also free. For a monospace you control across devices, JetBrains Mono and Source Code Pro are free on Google Fonts.
On Google Fonts: JetBrains Mono, Source Code Pro.
Finding a font does not license it. More in how to get a font you found, legally.
Get a similar look with a free font
This starter uses Inter, which is open source, with the sizes and spacing measured above. It is an approximation, not a copy of Stack Overflow’s brand typeface.
/* Approximates the Stack Overflow look with a free font */
body {
font-family: "Inter", system-ui, -apple-system, "Segoe UI", Roboto, Arial, sans-serif;
}
h1 {
font-size: 1.6875rem; /* 27px */
font-weight: 400;
line-height: 1.3;
}
p {
font-size: 0.8125rem; /* 13px */
font-weight: 400;
line-height: 1.31;
}How we checked
We opened stackoverflow.com in Chrome on November 5, 2026 and read the computed styles of its visible text: the declared font stack, the font actually rendered, and how much of the page’s text each family sets. That is the same data the Font Inspector extension shows under Fonts on this page. We re-check these pages periodically, and the date above shows the last inspection.
Stack Overflow and its typefaces are trademarks of their respective owners. Font Inspector is not affiliated with Stack Overflow.
Questions & answers
What font does Stack Overflow use on its website?
Stack Overflow uses no web font at all. Text is set in the system font stack, so you see Segoe UI on Windows, San Francisco on a Mac and Roboto on Android, with the system monospace font for code.
Can I use the Stack Overflow font?
Free to use: name the system fonts in your CSS and each device supplies its own. Nothing to license or download.
How can I check what font Stack Overflow uses myself?
Open stackoverflow.com, then click any text with the Font Inspector extension, or right-click, choose Inspect and look at Rendered Fonts in the Computed tab. Sites change their typography, so checking the live page is the only way to be sure.