Lesson 3 - Cash Flow: Income vs. Expenses
Cash flow is your monthly story in numbers. Income comes in, expenses go out, and the difference is your surplus or deficit. When you control this flow, everything else gets easier.
What is cash flow?
Cash flow is income minus expenses for a period, usually a month. If the result is positive, you have a surplus you can save or invest. If it’s negative, you are funding your life with debt or draining savings.
Focus on three levers you can actually move: raise income, cut expenses, and automate saving so money leaves to the right places before you touch it.
Fixed vs. variable expenses
Fixed costs stay similar each month (rent, phone plan, subscriptions). Variable costs bounce around (food, transport, fun, shopping). You cut stress by shrinking fixed costs first, then tightening variable costs with simple rules.
Mini case study - Sara turns red into green
Sara is 20, studies marketing, and works weekends. She felt stuck because her card balance kept creeping up. We mapped her month. Income: 620 € from work and 180 € from freelance designs. Expenses: 450 € rent share, 60 € phone, 40 € subscriptions, 180 € food on campus, 120 € rideshares and buses, 90 € random shopping. Result: −140 €. Two changes flipped it. She switched to a cheaper SIM and split streaming with her cousin, dropping fixed costs by 18 €. Then she set a weekly food cap and cooked twice per week, saving ~60 €. She also added one extra freelance logo per month (+70 €). New result: +8 € the first month, then +70–100 € after habits stuck. The win was boring but real: smaller fixed costs, a simple food rule, and one extra invoice.
How to map your cash flow
- Write down monthly income sources and their averages.
- List fixed expenses first, then variable expenses by category.
- Income − expenses = surplus or deficit. If negative, reduce fixed items and set two simple rules for variable items.
Interactive cash flow planner
Pick a currency, adjust the sliders, and see your surplus or deficit. The chart has its own row to avoid overlap.
Quick recap
- Cash flow = income − expenses. Aim for a consistent surplus.
- Lower fixed costs first. Then apply simple rules to variable costs.
- Automate saving so the surplus moves out before you can spend it.
Key Terms
Further Learning
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