Personal Budget Lab
Practice building a real budget. Allocate your income across expense categories, track savings growth over 12 months with compound interest, and test what-if scenarios like job loss, a raise, or an unexpected expense.
Guided Experiment: Build Your First Budget
If you follow the 50/30/20 rule (50% needs, 30% wants, 20% savings), will you have positive monthly cash flow?
Write your hypothesis in the Lab Report panel, then click Next.
Savings Growth (12 Months)
Controls
Monthly Allocation
50/30/20 Analysis
Data Table
(0 rows)| # | Month | Income($) | Total Expenses($) | Monthly Savings($) | Emergency Fund($) | Net Worth($) |
|---|
Reference Guide
Compound Savings Growth
When you save money in an interest-bearing account, your savings grow exponentially over time.
Where r is the annual return rate and S is the monthly savings contribution. Each month, interest is earned on the entire balance before new savings are added.
The 50/30/20 Guideline
A widely used framework for balanced budgeting. Needs should stay under 50%, wants under 30%, and savings should be at least 20%.
This lab lets you experiment with different allocation percentages and see the long-term impact on your financial health.
Emergency Fund Planning
Financial advisors recommend maintaining 3 to 6 months of living expenses in savings.
The lab tracks how quickly your emergency fund reaches this goal based on your savings rate and interest earned.
What-If Scenarios
Real life is unpredictable. This lab lets you simulate three common financial shocks.
Job loss sets income to $0 for 3 months. Raise increases monthly income at a chosen month. Unexpected expense adds a one-time cost.
Seeing the impact of these events helps you understand why an emergency fund matters and how savings rates affect resilience.
