Monthly Budget Optimizer
Breaks down monthly income against categorized expenses to calculate surplus or deficit, category-level spending percentages, and overall savings rate. Flags categories that exceed recommended thresholds and projects annual impact of current habits.
Personal - Monthly Budget Optimizer.xlsx
Excel (.xlsx) — No macros — Works in Excel, Google Sheets, LibreOffice
What This Spreadsheet Solves
- No clear picture of where money goes each month
- Spending exceeds income without knowing which categories cause it
- Savings rate is unknown or inconsistent
- Difficulty comparing actual spending to recommended budget ratios
- No early warning when a category trends over budget
Who This Is For
- Individuals building or refining a personal budget
- Households tracking joint income and shared expenses
- Financial coaches reviewing client spending habits
- Young professionals establishing spending discipline
Inputs
- $Monthly Net Income
- $Housing Costs
- $Transportation Costs
- $Food & Groceries
- $Discretionary Spending
- %Target Savings Rate
Outputs
- Monthly surplus or deficit amount
- Spending percentage per category
- Actual savings rate vs target
- Categories exceeding recommended thresholds
- Projected annual savings at current rate
How Calculations Work
The model sums all expense categories and subtracts the total from net income to determine surplus or deficit. Each category is divided by total income to produce a percentage allocation. The savings rate is computed as (income minus expenses) divided by income. Categories are compared against configurable threshold percentages and flagged when exceeded.
Example Use Case
Scenario: A household earns $6,200/month net. Housing is $1,800, transportation $450, food $620, discretionary $900, and other fixed costs total $1,100. Target savings rate is 20%.
Result: Monthly surplus is $1,330 (21.5% savings rate), exceeding the 20% target. Housing consumes 29% of income (within the 30% guideline). Discretionary spending at 14.5% is flagged as above the 10% threshold. Projected annual savings: $15,960.
What You Get — 5 Sheets
Technical Details
Frequently Asked Questions
Should I use gross or net income?
Use net (after-tax) income. The budget optimizer calculates spending ratios against take-home pay, which gives a more accurate picture of discretionary capacity.
How are the recommended thresholds determined?
Defaults follow the 50/30/20 framework (needs/wants/savings). You can override every threshold in the CONFIG sheet to match your own targets.
Can I add custom expense categories?
Yes. Add rows in the INPUT sheet and assign them a category label. The LOGIC sheet picks up any named category automatically.
What if I have irregular income?
Enter the average of the last 3-6 months. For highly variable income, run the model with your lowest recent month to stress-test the budget.
Does this account for annual or quarterly expenses?
Divide annual expenses by 12 and enter the monthly equivalent. The model works on a monthly cycle; annualized projections multiply the monthly result by 12.
Download Monthly Budget Optimizer
Ready to use immediately. Enter your data in the INPUT sheet, see results in OUTPUT.