BusinessHWP

HWP vs HWPX: what changed, and which one to ask your Korean partner for

SENULA COMPANY · 2026-09-19 · 5 min read

Why these files keep arriving

Anyone doing business with South Korean companies, universities, or government offices will eventually receive files ending in .hwp or .hwpx. These are the standard word processing formats used across South Korea for contracts, certificates, tax forms, and internal reports. Outside Korea, almost no common software handles them natively.

Two formats, two very different architectures. Knowing which one you have determines how easily you can read, convert, or extract text from the document.

HWP 5.0: the binary format

HWP version 5.0, introduced in the early 2000s, stores everything inside a binary compound-file container. Text, images, styles, and metadata each sit in separate binary streams within the single file. The structure resembles the old Microsoft .doc format.

Because of this proprietary binary design, third-party support remains limited. Software that opens an HWP file must decode byte-level sequences to reconstruct the layout. Many document viewers simply refuse to open older HWP files, and those that try often produce garbled text, misplaced images, or blank pages.

Despite being over two decades old, HWP 5.0 files remain extremely common. Private companies, law firms, and individual users still produce them daily.

HWPX: the XML-based successor

HWPX follows the OWPML standard (KS X 6101) and uses an XML-based architecture. Rename an .hwpx file to .zip, extract it, and you find organized folders of XML files describing the document structure, styling, and embedded resources.

This openness mirrors the .doc-to-.docx transition Microsoft made. Parsing XML is straightforward compared to decoding binary streams, so HWPX files are far easier for third-party tools to handle. Since the early 2020s, Korean public institutions have been migrating their official documents to HWPX and other open formats.

The font problem that breaks every layout

Opening either format on a machine outside Korea almost always produces a distorted layout. The cause is not the file format itself. It is the missing fonts.

Korean documents rely on specific typefaces such as Batang and Gulim, designed for the Hangul writing system. Hangul characters are syllable blocks built from consonants and vowels, and the spacing metrics in Korean fonts account for this unique structure. When your operating system lacks these fonts, it substitutes a default western typeface. The replacement font has different character widths, line heights, and kerning values, so text reflows. A paragraph that fit neatly on one page spills onto the next, pushing tables, stamps, and signature boxes out of position.

Worked example: a supplier contract

You receive a 14-page supply agreement from a manufacturer in Incheon. The file is named 공급계약서_2026.hwp and weighs 1.3 MB. You need to review payment terms on page 8 and forward the document to your legal team in London.

1. Check the extension. It ends in .hwp — the older binary format.
2. Drop the file into the HWP Viewer, which parses it locally in your browser without sending the file anywhere. The viewer renders the original page layout using substituted free fonts, so the structure stays close to the original. Header and footer images are not drawn yet, but body text, tables, and page breaks remain intact.
3. Navigate to page 8 and read the payment clause.
4. Save as PDF directly from the viewer. The PDF preserves the rendered layout and opens on any machine.
5. If your legal team needs editable text for translation, save as Word (docx) or plain text instead.

Total time from opening the email to handing your lawyer a readable PDF: under two minutes.

Worked example: university transcripts for a visa

A Korean university emails a set of academic transcripts for a student visa application. The file is 성적증명서.hwpx, 420 KB, and the immigration office requires a PDF.

You could rename the .hwpx to .zip and extract the XML to read raw grades. But the immigration office expects the formatted layout to match the official document. Add the file to the HWP Viewer, verify the page structure looks correct, and save as PDF. The viewer handles HWPX files with the same local-only processing as HWP files. No sign-up, no watermark, no file-size limit.

Format comparison at a glance

What to request from your Korean partner

The format you ask for depends on what you plan to do with the document.

• Read or print only. Ask for a PDF exported from the original software. A PDF embeds its fonts, so the layout stays fixed everywhere.
• Extract or translate text. Request HWPX. Its XML internals make text extraction simpler than binary HWP.
• Already have the file. Open it directly in the HWP Viewer to view the contents, then save in the format you need. The file never leaves your device throughout the process.

If a partner offers to send either format and asks your preference, pick HWPX. It gives you more options downstream and better compatibility with conversion tools.

FAQ

Can I edit an HWP or HWPX file in the viewer?

No. The viewer is read-only. It renders the document and lets you save it as PDF, Word (docx), or plain text. For editing, you need the original word processing software or a compatible editor.

Is it safe to use the viewer for confidential contracts?

The file never leaves your device. All processing happens in the browser with no server involved. Once the page has loaded, it works offline too.

Why do some pages look slightly different from the original printout?

Font substitution. The viewer replaces proprietary Korean fonts with free alternatives that have similar but not identical metrics. Small shifts in line breaks or spacing can occur. The overall page structure and text content remain accurate.