What the projection is designed to show
A projection estimates how the cash available to a household could change month by month under one set of assumptions. It begins with the scenario's starting cash, calculates each month's inflows and outflows, and carries the ending cash balance into the next month.
The result is designed for focused what-if planning. It helps reveal timing, lower-balance periods, negative-balance months, and differences between scenarios without attempting to model an entire financial life.
Income and expense inputs
- Income sources contribute their calculated amount when their recurrence and date window apply.
- Positive one-time events are added to the month's cash inflow.
- Bills contribute their calculated amount to cash outflow when their recurrence and date window apply.
- Living Costs contribute their monthly amount in every month inside their optional date window.
- Negative one-time events are added to the month's cash outflow.
Recurrence normalization
Weekly = amount × 52 ÷ 12 each eligible month
Biweekly = amount × 26 ÷ 12 each eligible month
Monthly = amount as entered each eligible month
Quarterly = full amount every 3 months from the start month
Annual = full amount every 12 months from the start month
One-time recurrence = full amount once in the start month
Quarterly and annual amounts are scheduled, not averaged across every month.
Dates and one-time events
The engine compares dates by calendar month. Recurring items begin in the month containing their start date and remain eligible through the month containing their end date. Living Costs with no start or end bound apply across the projection.
Amounts are not prorated for partial months. A one-time event applies in the calendar month containing its event date, as either inflow or outflow according to its direction.
Monthly net change
Monthly net change =
calculated recurring income + positive one-time events
− calculated Bills − monthly Living Costs − negative one-time events
Ending cash balance = previous balance + monthly net change
For the first projected month, the previous balance is the scenario's starting cash. Total net change is projected ending cash minus starting cash. Total projected inflow and outflow are the sums of the monthly totals across the scenario.
A negative monthly net change means modeled outflow exceeded modeled inflow in that month. It is a prompt to inspect the assumptions and available balance, not by itself a recommendation to accept or reject a decision.
Comparing scenarios
Each selected scenario is projected independently from its own starting cash, inputs, date windows, and projection length, using the same current calendar start month. The comparison then aligns their monthly ending balances on a shared calendar timeline and summarizes ending cash, net change, lowest balance, and first negative month.
A scenario with a longer projection can have months that another selected scenario does not. Differences are most directly attributable when starting cash, projection length, and unchanged assumptions match.
Limitations and assumptions
- Weekly and biweekly figures are stable monthly averages, not exact deposit or payment calendars.
- The engine works at calendar-month resolution and does not model daily liquidity or due-day ordering.
- Partial start and end months are not prorated.
- Taxes, investment returns, interest accrual, inflation, debt amortization, and account transfers are not calculated unless their cash effects are represented in the entered assumptions.
- Unexpected income, costs, and timing changes are absent unless the user models them.
- The projection does not evaluate affordability, credit approval, or the suitability of a financial decision.