Thai font · COMMERCIAL

IrisUPC

By Narongsak Chaiwong

Typography & Licensing Specialist, ThaiGraph · July 16, 2026 · Updated October 30, 2026

Information verified as of October 2026

อ่านหน้า ฟอนต์ IrisUPC เป็นภาษาไทย — พร้อมลิงก์ดาวน์โหลดและวิธีติดตั้ง →

What IrisUPC is

IrisUPC is a sturdy looped Thai sans-serif with marked thick–thin contrast, designed by Unity Progress Corporation in 1992 and licensed to Microsoft, where it ships bundled with Thai editions of Windows and Office in four styles — Regular, Bold, Italic, and Bold Italic. It is one of the original UPC (Unity Progress Corporation) Thai system faces that predate the later “New” versions of Angsana, Browallia and Cordia (there is no Iris New), and it covers both the Thai and Latin scripts.

For most Thai computer users IrisUPC is not a font they chose but one they inherited: it was installed with the operating system and quietly set as a default in older documents. That makes it a compatibility face first and a design choice second — if a legacy Thai document “just renders correctly,” a UPC-family font is often why.

Character and the UPC vs New distinction

There is no Iris New: in Microsoft’s Windows 11 font list the only UPC families with “New” counterparts are Angsana, Browallia and Cordia, and Iris exists only as the four IrisUPC styles. (Windows 11 font list, accessed 30 October 2026) What sets IrisUPC apart shows in the font file itself: the Thai is a looped (มีหัว) sans with marked thick–thin contrast and narrow oval loops, but the bundled Latin is a serif, not a sans like the Thai, and its 46 Thai consonants average 0.40 em wide, narrower than FreesiaUPC (0.43 em), another looped sans in the set (measured from Upcil.ttf, version 5.05, on 30 October 2026).

As a sans-serif face it sits in the traditional Thai text category rather than the modern loopless movement covered in our typography guide. The Latin companion is a straightforward text alphabet included so mixed Thai–English lines can be set from a single family.

Weights and availability

IrisUPC ships in four styles — Regular, Bold, Bold Italic, and Italic — and is distributed exclusively bundled with Microsoft Windows and Office, not as a separate download. It has been present in Windows from Windows XP through Windows 11, and is also available inside Office applications.

To check whether you already have it, open the font menu in Microsoft Word or your system font settings and look for “IrisUPC”. Because it is a system font, there is no legitimate free-download source — it arrives with the platform.

On a fresh or upgraded Windows 10 or 11 install, IrisUPC stays absent until you switch on the Thai Supplemental Fonts optional feature under Settings → System → Optional features (Microsoft Learn, accessed 30 October 2026). The step-by-step is on our Thai fonts built into Windows page; to confirm you have it, open C:\Windows\Fonts and look for IrisUPC (files Upcil.ttf, Upcib.ttf, Upcii.ttf and Upcibi.ttf).

Best use cases

IrisUPC earns its keep on compatibility and legacy Thai documents rather than new brand work. Strong fits:

• Opening, editing, and reprinting older Thai documents that specified the UPC family
• Government, academic, and office files that must render identically to their original
• Environments standardised on Microsoft Thai system fonts
• Situations that need a widely-installed, no-cost-to-the-user Thai sans-serif

For new design work, a modern licensed or open face — see the sans-serif category or Sarabun — usually serves better than a legacy system font.

Licensing

IrisUPC is a commercial font owned by Unity Progress and licensed through Microsoft; it is bundled with Microsoft products and is not free to redistribute or host as a webfont without a Microsoft licence. Confirm the terms on the Microsoft Learn typography page and the Office fonts documentation. See our Thai font licensing guide for how bundled system fonts differ from OFL and free faces.

Information verified as of October 2026