Write documents, crunch spreadsheets and edit PDFs in one fast desktop app. No subscriptions, no accounts, no ads. Your files stay on your computer.
Windows · macOS · Linux · System requirements
Word, Excel and PDF files open in tabs side by side. Save in familiar DOCX and XLSX formats, making it easier to exchange files with Microsoft Office users.
A familiar ribbon for letters, reports and theses. Opens and saves .docx, and opens .doc, .rtf and .odt.
Formulas, charts and real Excel features. Opens and saves .xlsx and .csv, and opens .xls and .ods.
More than a viewer. Change, sign and convert PDFs without uploading them anywhere.
A familiar ribbon for letters, reports and theses, with track changes, equations, citations and mail merge.
Formulas, charts, PivotTables, conditional formatting and sparklines, saved as standard .xlsx files.
Fill and sign, edit text, run OCR on scans and rearrange pages, all on your own computer.
Sixteen ready-made templates, from a resume and invoice to a budget, timesheet and loan calculator.
Light and dark themes. The page stays white, so what you see is what prints.
Every one of these ships in the free download. There is no paid version to unlock them.
Most people handle documents for free in one of two ways. Here is how they differ from Kertas.
Kertas OfficeDescribes common practice across popular freemium suites and online PDF services, not any single product. Other open-source suites, such as LibreOffice and ONLYOFFICE, share many of these values.
Our compatibility page lists, feature by feature, what round-trips cleanly with Microsoft Office, what is partial and what is still missing.
Kertas does every edit, conversion and signature on your own computer, so nothing needs to be uploaded. The only thing it asks the internet is whether a newer version is out, and you can turn that off.
Version 1.0. Built automatically from the public source on GitHub.
Kertas, Malay for paper, began as a solo side project with a simple idea: a good office suite should not come with ads, accounts or a paid tier. With version 1.0 it became an open project that anyone can use, inspect and improve.
Built to answer a frustration many people share: free office apps that nag, upsell or upload your files.
Every line of code is public under the AGPL-3.0 licence, so Kertas stays free for everyone, for good.
Plans, releases and known issues live on GitHub, where anyone can report a problem, suggest a feature or send a fix.
Read the code, report a bug, suggest a feature or send a pull request. Files that do not open correctly are especially helpful.
Kertas has no investors and no advertisers. Contributions pay for code signing, Apple's developer programme and development time, so the app stays free for everyone.
Other ways to help: tell a friend, translate the app, or answer questions in Discussions.
Kertas is built on open-source engines and released the same way. It is supported by its users, not by your data or a paid tier.
Kertas saves in the native .docx and .xlsx formats, and most documents round-trip cleanly. Very complex layouts may shift slightly. The compatibility page lists exactly what is partial.
Kertas started as a solo project and is now developed in the open by its contributors. Anyone can join on GitHub. It is not run by a company.
Every installer is built automatically by GitHub Actions from the public source code, so what you download matches what anyone can read. Code signing for Windows is being set up, so for now Windows may show an "unrecognised app" warning the first time. Here is what to do.Windows installers are signed through SignPath Foundation. Read our code signing policy.
No. Kertas focuses on documents, spreadsheets and PDFs, and aims to do those three very well.
Yes, for business, school and government use alike, at no cost. The AGPL licence only adds obligations for people who modify Kertas and distribute it or run it as a service.
Download once. No account, no trial, no ads.
Download Kertas Office