What Is SankeyMATIC?

SankeyMATIC is a free online Sankey diagram builder that runs in your browser. You type your flow data in a simple text format, and it draws a flow diagram you can style interactively and export as an image or vector file. It suits anyone who needs to show how amounts move between stages — budgets, financial results, application pipelines, multi-round elections — without installing software, writing code, or signing up for an account.

What a Sankey diagram shows

A Sankey diagram compares amounts as they pass through different stages. Instead of a bar or line chart, it draws flows as bands whose width is proportional to the amount, so you can see at a glance where volume enters, splits, and exits.

Typical uses named on the site include:

• Budgets and financial results
• The story of an application process
• Elections with multiple rounds

The common thread is a quantity that moves through stages and divides along the way.

How you enter data

The input format is a single line per flow:

Source [Amount] Target

Each line says that some amount flows from a source node to a target node. You list as many lines as you need, and SankeyMATIC turns them into a diagram. There is no code to write and no schema to configure — the structure of your diagram comes entirely from the source/target names you use.

Customizing the diagram

SankeyMATIC provides a wide array of interactive controls so you can adjust how the diagram looks. You change settings and see the result update, rather than editing a stylesheet or re-rendering by hand. This is where you tune the appearance after the data is in place.

Saving and exporting your work

You can get your diagram out in several forms:

The plain text save is worth noting for two reasons: you can resume your work later on any computer or in any browser, and you can compare versions of a diagram by diffing the source files.

What "use it freely" means here

According to the site, using SankeyMATIC involves:

• No extensions to install
• No code to write
• No email address required
• No sign-up or trial period

The site also notes you are welcome to contribute to support development if you like. The page does not state pricing terms beyond this, so treat the contribution as optional support rather than a required purchase.

When to use it

SankeyMATIC fits well when you want a flow diagram quickly and want to control its look without a design tool. It's a good match if you:

• Need to show amounts moving through stages
• Prefer typing data over dragging shapes
• Want a PNG or SVG you can drop into a page or deck
• Want to keep an editable, diffable copy of the diagram

If your goal is a static chart of categories rather than flows between stages, a different chart type will usually communicate better.