Use the right tool
Cash flow measures timing; monthly expenses measure average cost.
Use this projection for near-term liquidity. Use the Monthly Expenses Calculator to convert weekly, quarterly and annual costs to comparable monthly amounts.
Cash-flow calculator
Personal Cash Flow Calculator
Project four weeks of money in and money out. See the lowest balance, not only the month-end total, so a timing gap does not disappear inside a positive monthly average.
Four-week projection
Enter when cash arrives and leaves
Week 1
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Week 2
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Week 3
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Week 4
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What counts as available cash?
Use money that can cover the listed payments. Do not count an overdraft or credit limit as cash. Put each expected receipt and payment in the week it is expected to clear.
Method
Each week starts where the previous week ended.
The calculation is prior balance + income received − expenses paid. The lowest projected balance is the minimum of the opening balance and every weekly ending balance. A positive month-end result can still contain an earlier shortfall.
Source
Budgeting starts with the timing of income and expenses.
The US Consumer Financial Protection Bureau includes a cash-flow budget in its Your Money, Your Goals toolkit to help people track the timing of money coming in and going out.
Consumer Financial Protection Bureau — Your Money, Your Goals toolkit