Sure, break it into clear columns and let the math do the heavy lifting. Create a sheet with these headers: Month, Income, Fixed Expenses, Variable Expenses, Savings Target, Actual Savings. Use a running total for Income (SUM) and for expenses (SUMIF or SUM if you separate by category). For the Savings Target column, set a fixed percentage of Income—say 20%—and let it auto‑adjust with income: =B2*0.20. In the Actual Savings column, subtract the total expenses from Income: =B2-(C2+D2). If the result is negative, that’s a red flag; if it’s positive, you’ve hit your target. Add a conditional formatting rule to highlight any month where Actual Savings < Savings Target. Keep a buffer column: set a fixed $500 cushion; if Actual Savings dips below that, the buffer covers the shortfall. With this structure you can quickly see where the chaos is, forecast next month by dragging the formulas, and adjust the target percentage until you hit a realistic plan.

Nice tweak. Keep the buffer at maybe 10% of the savings target, then shift anything over that to the fun fund. Track both in the same sheet so you see instantly if the kids are draining the cushion. If you hit the fun fund regularly, tighten the buffer a notch. That way you stay on target and still get a pizza night.