Who asked: Harper and Jules, who share a fictional household budget.
Why: their bank export lists transactions, but they need to know which categories used their plan and whether the month stayed within the overall budget.
Data: Transactions contains 12 September records. Positive Outflow means spending; the negative grocery record is a refund. Budget holds five category plans, including a zero Gifts plan with no spending. These are fictional practice amounts.
Deliverable: a running outflow column, category actuals and remaining budgets, utilization, category status, totals, an exception list, an overall finding, and a chart comparing planned with actual amounts. Add a category dropdown that rejects unknown entries and highlight overspent categories. Keep the raw transactions available.
A budget tracker needs consistent signs and a clear denominator. Here, spending is positive and refunds are negative. Summing those amounts gives net outflow. Taking absolute values would make a refund look like extra spending and overstate the actual total.
Build the workbook in order. The transaction running total helps inspect the sequence, while the Budget tab groups those same records by category. A category with no plan needs an explicit rule for its utilization ratio; returning a division error would make the report harder to use.
The final report separates a category exception from an overall result. Groceries can be over its plan while another category has money left. Decide the overall status from the total plan and total actual, then keep the category exception list beside it.