Step 1: Map the pay period
List the current balance, expected income, bills, subscriptions, groceries, transportation, goals, and a buffer.
Step 2: Protect essentials
Subtract must-pay items first, then planned expenses, then the buffer. The remaining number is closer to safe-to-spend.
Example
If $800 is available but $520 is due before payday and you want a $100 buffer, only $180 is flexible.