Cash Flow (CF)
Cash Flow (CF) measures the net movement of actual money in and out of a project or business over a period of time. "Cash in" is the money you receive (like customer payments), and "cash out" is the money you spend (like paying suppliers, salaries, or rent). To calculate it, you simply subtract the total cash going out from the total cash coming in for that period.
Reading the result is easy: a positive cash flow means more money came in than went out — a healthy sign that you have cash available to cover expenses. A negative cash flow means you spent more than you received, which can signal trouble if it continues, because you may run short of money to pay your bills even if the project is profitable on paper.
A project manager watches cash flow to keep the project "liquid," meaning it always has enough ready cash to keep operating. This is different from profit — a project can look profitable overall but still run out of cash at the wrong moment, so tracking cash flow month by month helps avoid nasty surprises.
Think of it like the balance in your personal checking account. Money from your paycheck flows in, and rent, groceries, and bills flow out. At the end of the month, if more came in than went out, your balance grows; if not, it shrinks — and if it hits zero, it doesn't matter how good your salary looks on paper, you still can't pay for dinner.
Imagine that during one month your project receives $50,000 in payments from a client (cash in) and pays out $38,000 for materials, wages, and equipment rental (cash out). Your cash flow is $50,000 − $38,000 = $12,000. That positive $12,000 tells you the project generated more cash than it consumed this month, so you have a comfortable cushion to carry into the next period.
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