Visualize Money Flow with Sankey Diagrams

A Sankey diagram shows where your money comes from and where it goes using flowing lines of different widths. Wider lines mean more money. It is one of the most intuitive ways to understand your financial picture at a glance.

What Is a Sankey Diagram

A Sankey diagram displays flows. On the left side, you have your income sources: salary, side income, investment returns. On the right side, you have your spending destinations: housing, food, transportation, savings.

Lines connect income to spending categories. The width of each line represents the amount of money flowing through it. A line going to rent might be thick. A line going to subscription services might be thin.

Why Sankey Diagrams Work

Proportions become immediately visible. Numbers in a table require mental math to compare. In a Sankey diagram, you instantly see that housing takes 35% of income because the line is visibly one-third of the total flow.

Hidden expenses surface. When you see that dining out, coffee shops, and food delivery combine into a flow nearly as wide as groceries, patterns become obvious.

Savings rate is visual. The line flowing to savings (or debt payment) tells you immediately whether you are building wealth or just churning money through your accounts.

Common Patterns in Money Flow Diagrams

Housing dominance. For most people, the housing line (rent or mortgage) is the widest single flow, often 30% to 40% of income.

Scattered discretionary spending. Small categories like subscriptions, entertainment, and shopping often combine into surprisingly large total flows.

Thin savings lines. Many people are surprised to see how small their savings flow looks compared to their spending flows.

Surprise categories. Transportation, insurance, and food frequently take larger shares than people estimate.

How to Use Sankey Diagrams

Current state analysis. Create a diagram showing your actual money flow from the past few months. Look for surprises.

Goal visualization. Create a diagram showing your ideal money flow. How thick should the savings line be? Where could you reduce flows?

Trade-off exploration. What if you moved 5% of income from dining out to investments? Visualize the change.

Progress tracking. Compare diagrams from different time periods to see how your money flow has changed.

Level of Detail

Too few categories and the diagram lacks insight. Too many and it becomes cluttered. For most people, 15 to 25 final destinations provides good balance.

Consider grouping small categories. Instead of separate lines for Netflix, Spotify, and gym membership, a single subscriptions line may be clearer.