Sankey Diagram Maker

What Is a Sankey Diagram?

A Sankey diagram is a flow diagram whose ribbons are sized by the quantity moving along them. Each node is a stage, each ribbon is a flow, and the width of that ribbon is proportional to its value — so the eye reads proportion directly instead of decoding a legend. It is also called a flow diagram, a flow chart with weighted arrows, or, when the emphasis is on items being reclassified over time, an alluvial diagram. This SlideModel tool builds all of them from the same rows, free and in your browser.

Reach for one when the question is where does it all go. Money enters as a budget and leaves as outcomes. Visitors arrive from channels and end as conversions or drop-offs. Energy enters as fuel and leaves as power and losses. A money flow diagram, a budget flow chart, a conversion funnel flow, and a material flow analysis are all the same picture applied to different quantities.

Why PowerPoint and Excel Can't Make a Sankey Diagram

Neither PowerPoint nor Excel has a Sankey chart type. There is no menu entry to find and no template that fixes it, because the shape itself — a curved ribbon whose thickness encodes a value and whose ends align to stacked node bars — is not something Office's chart engine can express.

So people do one of two things. They draw the ribbons by hand from curved shapes, which takes an afternoon and is never actually proportional, so the diagram misrepresents the data it is meant to show. Or they buy a PowerPoint add-in. This maker is the third option: build a Sankey diagram online, free and with no account, and with Pro take away a PowerPoint file whose ribbons are genuine editable shapes rather than a flat picture.

Sankey vs Flow Chart, Alluvial, Chord, and Funnel

These five get confused constantly, and picking the wrong one is the usual reason a process slide fails to land.

Diagram	The question it answers	Ribbon width means	Direction
Sankey	Where does the quantity go as it moves through stages?	The value of that flow	One way, source to sink
Flow chart	What are the steps and decisions?	Nothing — arrows are uniform	One way, can loop
Alluvial	How are items reclassified between categories over time?	Size of that group	One way, across time steps
Chord	How much moves between members of one set?	Volume between the pair	Both ways, circular
Funnel	How many survive each stage of one path?	Stage size	One way, no branching

If your data has a source set and a target set that differ, you want a Sankey. If both ends are the same set of entities — countries trading with each other, teams handing work back and forth — you want a chord diagram instead.

How to Make a Sankey Diagram

1. Enter your flows. Each row is a source, a target, and a value. Copy three columns from Excel or Google Sheets and paste them in, or type them by hand. Multi-stage diagrams just chain: what is a target in one row becomes a source in the next.
2. Check the data. If a node has more going in than coming out, the tool says so. If a chain loops back on itself it names the nodes involved, because a Sankey cannot be laid out with a cycle. Fix it or confirm it is intentional.
3. Compare a period, if you have one. Add a fourth column with last year's figures and the diagram will show what grew and what shrank.
4. Style it for your deck. Choose how ribbons are coloured, switch between curved and straight, adjust opacity so overlapping flows stay readable, and pick a palette and background.
5. Download. Take a crisp PNG for free. With Pro you can also download a vector SVG or use Insert into slide for an editable PowerPoint file.

Comparing Against Last Year

Most Sankey tools show one moment. The interesting question in a business review is usually not where does the money go but where does it go differently than it used to, and answering that normally means putting two diagrams side by side and asking the audience to hold both in their head.

Add a fourth column with the previous period and this diagram answers it directly. Three encodings, which combine:

• Change labels append the delta to each node: 62 (+18). Precise, and it survives being printed in black and white.
• Colour by change tints every ribbon green where it grew and rust where it shrank, so the shape of the shift is visible before anyone reads a number. The pair is deliberately green and rust rather than green and red, so it stays readable for the most common form of colour blindness.
• Growth and loss bands draw the difference itself over each ribbon, so the size of every change is a visible area rather than a figure to compare mentally.

The previous period gets its own balance check too — a prior year that does not reconcile is worth catching before it appears on a slide with your name on it.

What People Use Sankey Diagrams For

Finance and strategy teams map revenue by segment through to renewals and churn, or an income statement from revenue down to net profit. This is the use case the comparison column was built for: a board wants this year against last, in one picture.

Marketing and growth teams show budget flowing into channels and out as leads, conversions, and spend that produced nothing. The diagram makes the drop-offs impossible to skip past, which is usually the point.

Operations and sustainability teams build an energy flow diagram or a material flow analysis — fuel in, useful output and losses out. Losses are visible as ribbon width rather than a footnote, which is exactly why engineers have used this form since Sankey drew the first one in 1898.

Product and CX teams chart customer journeys and churn paths, showing how users move between states across a quarter.

Reading and Presenting One Well

A Sankey diagram is not self-explanatory, and it rewards a caption that states the takeaway. Give the slide a title that says what the flow shows rather than what the chart is, keep node names short enough to read from the back of a room, and turn node totals on so the audience can anchor the proportions to real numbers.

The chart's honest weakness is precision: if two ribbons are close in width, no reader can reliably say which is larger. Put the numbers in the labels whenever exact figures matter — this tool does that by default. When a diagram gets crowded, the two most effective fixes are combining small flows into an "Other" node and increasing node spacing so the ribbons have room to separate. Colouring by source helps a reader follow one origin across the whole diagram; colouring by target shows what fed each outcome.

Built for Slides, Not for Dashboards

Most Sankey tools are data-visualization utilities that hand you a flat image in one default look. That image then has to live on a slide it was never designed for, in colours that match nothing else in the deck.

This one starts from the slide. The canvas is a fixed 16:9 frame, so the preview is what you will paste. Palettes are picked to survive a projector and a grayscale printout. Transparent backgrounds are available from the start, not held back as a paid feature, because a diagram usually has to sit on your own slide background.

With Pro, the Insert into slide export writes a PowerPoint file where each ribbon is a genuine freeform shape and each node is a rectangle. You can click a single flow, change its colour to your brand palette, nudge a label, or restyle the whole diagram without leaving PowerPoint. Competing tools either sell a PowerPoint add-in for this or export a picture you cannot touch.

Once the diagram is built it still needs a deck around it. SlideModel publishes thousands of editable presentation templates for PowerPoint and Google Slides, so the flow diagram you export here can drop into a data-story layout that already matches it — and the rest of the free presentation tools cover the other slides in the same deck.