Profit and cash are not the same question. A business that is profitable on paper can still run out of cash the week a quarterly tax bill or an insurance renewal lands on top of the usual bills, because invoices arrive later than the costs they are meant to cover. The date that matters is not the lowest week in a forecast — it is the first week the running balance goes negative, because that is the date an invoice or a bill has to move in front of.
Open the free cash runway planner
Payments that do not repeat. A forecast built only from a smoothed weekly average answers "cash stays positive" to an owner who is about to be $3,000 down the week the quarterly tax bill clears — which is worse than no answer, because they believe it.
The first negative week versus the lowest week. Covering only the deepest week's shortfall can still leave a business short earlier in the run; the first negative week is the date to act, the deepest week is how much to move.
Structural gaps disguised as timing problems. If weekly costs already exceed weekly collections before any one-off payment is counted, moving one payment around only postpones the same shortfall — it does not fix it.
Starting cash, weekly income with a two-week collection delay, and weekly costs project a first shortfall in week 2, $3,000.00 short at the low point. A Quarterly tax payment of $6,000.00 is scheduled in week 2; moving it past week 5 closes the gap entirely. Alternatively, an Invoice 118 for $4,000.00 due in week 6 would close the gap if collected before week 2. The planner reports both options and states plainly when neither can help — because weekly costs already exceed weekly income, which is a structural gap no scheduling change fixes.
Forecast weekly balance from starting cash, weekly invoiced income delayed by your collection lag, and weekly costs, then schedule the payments that do not repeat — a quarterly tax bill, an insurance renewal, a deposit you are owed — in the exact week each lands. The answer is the first week the running balance goes negative, not a smoothed average.
Both, for different reasons. How much to move is sized off the deepest week in the negative run, because covering only the first week's gap leaves you short again days later. When to act is the first negative week, because that is the date the fix has to already be in place — by the trough it is too late to move anything dated earlier.
Delaying only helps an outflow dated at or before the shortfall starts, so the planner looks there and picks the largest one. Pulling money forward only helps an inflow dated after the trough, so it picks the earliest one large enough to matter. If weekly costs already exceed weekly income before any one-off is counted, moving a payment only postpones the shortfall — the planner calls that out as a structural gap, not a timing problem.