Financial Tools
Free Cash Flow Sankey Calculator
Map your income and expenses into a clear money-flow diagram — and see how much is left to invest each month.
Quick Answer: This free cash flow calculator turns your monthly income and expenses into a Sankey money-flow diagram. Add each income source and expense category — the tool draws the flow live and computes total income, total expenses, your surplus (or deficit) and your savings rate. Everything stays in your browser: no signup, no server. Load the example to see it instantly.
This tool is for your own household overview only. Your entries stay locally in your browser (no server, no transfer). Not investment, tax or financial advice.
See Your Cash Flow — Then Grow What's Left to Invest
Most budgets are a wall of numbers. A Sankey diagram turns that wall into a picture: every income source flows into one central budget, and out the other side into your expense categories — with whatever remains flowing into a clearly visible surplus. The width of each stream is its size, so the biggest drains on your money are impossible to miss.
That surplus is the number that matters most for building wealth. It is the fuel you feed into a portfolio each month. The whole approach I follow — hard assets and dividends — depends on a consistent monthly amount going to work. The clearer you can see your cash flow, the easier it is to find categories to trim and grow the amount you invest. Once you know your surplus, the Dividend Income Calculator and Dividend Snowball Calculator show what that stream can compound into over time.
How It Works — 4 Steps
- Add your income — salary, dividends, side income. One row per source.
- Add your expenses — rent, groceries, transport, insurance, leisure, and your monthly saving/ETF contribution.
- Read the flow — the diagram redraws live; the KPI strip shows total income, expenses, surplus and savings rate.
- Optimise — spot the widest expense streams, trim where it makes sense, and watch your surplus grow.
Frequently Asked Questions
What is a cash flow Sankey diagram? A Sankey is a flow chart where the width of each stream is proportional to its value. Your income sources flow into one budget node, then split out into expense categories plus whatever is left over as surplus or savings. It makes it instantly visual where your money goes.
How do I calculate my savings rate? Savings rate = (total income − total expenses) ÷ total income, as a percentage. Earn €3,680 and spend €2,120, and your surplus is €1,560 — a savings rate of about 42%. The tool calculates this automatically as you type.
Is my budget data stored anywhere? No. All calculations run in your browser and your entries stay in your own browser storage only. Nothing is sent to a server and no account is required.
Why does cash flow matter for investing? Your monthly surplus is the fuel for building a portfolio. Seeing the flow clearly helps you trim categories and grow the amount you can put into dividend-paying hard assets each month. The bigger and steadier the surplus, the faster compounding works.
This tool is an educational household-budgeting aid. Nothing here is investment, tax or financial advice. Always do your own research and consult a licensed advisor for personal financial decisions.
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