# TreeSheets

> Open-source hierarchical spreadsheet for free-form notes and data

TreeSheets is a free, open-source data organizer that its author calls a hierarchical spreadsheet. Information goes into grids of cells, and any cell can contain another grid, so a document nests like an outline while laying out in two dimensions. It is pitched for to-do lists, planning, brainstorming and other loosely structured data, and runs on Windows, macOS and Linux.

- **Category:** Note-Taking Apps
- **Made by:** Wouter van Oortmerssen
- **Website:** https://strlen.com/treesheets/
- **Runs on:** Windows, macOS, Linux
- **Facts last checked:** Oct 9, 2026

## Pricing

TreeSheets is free to use.

- **Pricing model:** Free
- **Free plan:** Free and open source under the zlib license. Every build is a free download from the project's GitHub releases, and there is no paid edition.
- **Free trial:** None listed.

| Plan | Price | What you get |
| --- | --- | --- |
| TreeSheets | $0 | The full app for Windows, macOS and Linux, with Debian packages, AppImages and a Flatpak for Linux. |

Read from https://strlen.com/treesheets/ on Oct 9, 2026. Prices change, so confirm with TreeSheets before buying.

## Key features

- **Grids inside grids:** Any cell can hold its own sub-grid, so data nests to any depth while keeping a spreadsheet-like layout of rows and columns.
- **Shrinking and zooming:** Text size is relative to nesting depth, cells can shrink to a pixel per character, and the mouse wheel zooms into a nested grid to make it readable.
- **Automatic layout:** Cells resize to fit their content after every edit, and a column-width setting controls how the text in a cell wraps.
- **Images in cells:** An image can be added to any cell and is stored as part of the document file, then copied to other cells in the sheet.
- **Import, export and indented text:** Documents export to XML, HTML or text and import from XML. Pasting text indented by hierarchy level rebuilds that structure as a tree.
- **Small footprint:** The author reports about 5 MB of memory on Windows 7 with several documents loaded, so it can stay in the system tray.

## Good for

- Brainstorming and planning that outgrows a flat outline
- People who want structure in two dimensions, not just indentation
- Desktop users who want a small, fast organizer on any major OS

## Worth knowing

- Desktop only: builds are offered for Windows, macOS and Linux, and the project lists no mobile or web version.
- Each cell is edited as a single line of text with optional word wrap, so it does not work like a rich text editor.
- The written tutorial on the website is marked as out of date; the current one is a document that opens inside the app.
- Documents are saved as .cts files, so using the data in other software means exporting to XML, HTML or text.

## Works with

Claude Code

**Tags:** Open source, Local-first, Notes

## Alternatives

- [Workflowy](https://toolgpa.com/tools/workflowy): Outliner that keeps notes, to-dos and plans in one nested list. [Compare](https://toolgpa.com/compare/treesheets-vs-workflowy)
- [Dynalist](https://toolgpa.com/tools/dynalist): Outlining app for nested lists, notes and tasks. [Compare](https://toolgpa.com/compare/dynalist-vs-treesheets)
- [OmniOutliner](https://toolgpa.com/tools/omnioutliner): Outliner for Mac, iPhone, iPad and Apple Vision Pro. [Compare](https://toolgpa.com/compare/omnioutliner-vs-treesheets)
- [CherryTree](https://toolgpa.com/tools/cherrytree): Hierarchical desktop notes with rich text and code highlighting. [Compare](https://toolgpa.com/compare/cherrytree-vs-treesheets)
- [NoteCase Pro](https://toolgpa.com/tools/notecase-pro): Cross-platform outliner and note manager with Lua scripting. [Compare](https://toolgpa.com/compare/notecase-pro-vs-treesheets)

## Sources

The prices, plans, platforms and features above were read from these pages on Oct 9, 2026:

- https://strlen.com/treesheets/
- https://strlen.com/treesheets/docs/tutorial.html
- https://github.com/aardappel/treesheets
- https://github.com/aardappel/treesheets/releases/latest

Page: https://toolgpa.com/tools/treesheets
Listed by ToolGPA (toolgpa.com).