This is one of the more counterintuitive realities of running a business, and it catches a lot of otherwise careful owners off guard — a P&L statement can show a healthy profit for the month, while the bank account tells a much tighter story.
Profit is an accounting measure; cash flow is a timing measure
Profit counts revenue when it's earned (often when invoiced) and expenses when they're incurred, regardless of when money actually changes hands. Cash flow only cares about money that has actually moved in or out of your account, right now.
How this plays out in practice
Say you invoice a client for $5,000 in March, and it counts as March revenue on your P&L. If that client doesn't actually pay until May, your March P&L looks great, but your March bank account doesn't reflect that money at all — and if you have bills due in March, you can be profitable on paper and still short on cash.
Inventory purchases create the same gap in reverse
Buying a large batch of inventory is a cash outflow immediately, but the cost only shows up on your P&L gradually as that inventory actually sells. You can be cash-poor from a big inventory purchase while your P&L still looks fine.
Why both need to be watched separately
A P&L statement answers "is the business fundamentally profitable." A cash flow view answers "can I pay this month's bills." Both are necessary — a business that's profitable but consistently short on cash needs to fix collection timing or spacing out big purchases, not the underlying business model.
A simple habit that helps
Alongside your P&L, keep a running sense of what's actually been collected versus what's just been invoiced — even a basic list of outstanding client payments gives you a much clearer read on near-term cash than the P&L alone.