irs.gov draws its headings and body text in Source Sans 3. That is the only custom font on the page. We measured it on November 4, 2026.
The fonts irs.gov draws
| Font | Used for | Share of its custom-font text | Licence | How common |
|---|---|---|---|---|
| Source Sans 3 | Headings, Body text | 100% | Open source | 17 of 845 sites (rank 6) |
Share is how much of the page’s custom-font text each font draws. System fonts and icon fonts are never counted. Each site was opened twice in a real browser and Chrome was asked which font file drew each piece of text. We count a font for a site only if both runs saw it and it drew at least 2% of the site’s custom-font text. The full method.
Can I use the same fonts?
- Source Sans 3 is open source and free to use, including commercially. Get it from Google Fonts.
irs.gov among nonprofit, government and reference sites
irs.gov is one of the 37 nonprofit, government and reference sites we measured. Across them, Open Sans is the most used font you can get, on 6 of the 37 (16%). All the fonts nonprofit, government and reference sites use.
What pairing does irs.gov use?
irs.gov uses one family, Source Sans 3, for both headings and body text. So do 567 of the 845 sites we analyzed (67%). Pairings of two different fonts.
Other nonprofit, government and reference sites we measured
- greenpeace.org Source Sans 3, Greenpeace Sans
- noaa.gov Nunito Sans, Source Sans 3
- usa.gov Source Sans 3, Merriweather
- arxiv.org IBM Plex Sans
- bl.uk Hind
- canada.ca Noto Sans, Lato
See the fonts on all 845 sites.
FAQ
What font does irs.gov use?
irs.gov draws its headings and body text in Source Sans 3. We measured it on November 4, 2026.
Is Source Sans 3 free?
Yes. Source Sans 3 is open source and free for commercial use, according to Google Fonts.
What font pairing does irs.gov use?
One family, Source Sans 3, for both headings and body text.
Can I use the same fonts as irs.gov on my own site?
Only if the licence allows it. Free and open-source fonts can be used freely. Commercial fonts need your own licence, even though you can see the file on irs.gov. Each font's licence is on this page, from its source.
How do you know which font irs.gov uses?
We opened irs.gov in a real browser and asked Chrome which font file drew each piece of text, twice in separate sessions. A font counts only if both runs saw it and it drew at least 2% of the site's custom-font text.
Can I check a different website?
Yes. Paste its address into the free font finder.