A basic cash flow forecast can help you see problems months before they arrive, and you do not need complex models to get there. A simple spreadsheet, updated weekly in under an hour, delivers 90 percent of the benefit. The goal is clarity: how much cash you have today, what is coming in, what is going out, and where the gaps are.

Set up your sheet with weeks across the top and categories down the left. Start with your current bank balance in week one. Under inflows, list expected customer payments, new sales you are confident will close, and any financing. Under outflows, list payroll, rent, subscriptions, contractors, loan payments, taxes, and inventory purchases. Avoid too much detail; keep categories broad so the sheet stays manageable.

Build the math so the sheet tells a clear story. The formula should be: Beginning cash + Total inflows - Total outflows = Ending cash. Then set the next week's beginning cash equal to the previous week's ending cash. This structure makes it easy to see how each line item affects runway.

Capture assumptions alongside the numbers. Note expected payment dates, invoicing cadence, and any one-time expenses. This makes the forecast explainable, not just accurate. It also helps you revise quickly when a deal slips or a vendor raises prices.

Keep categories stable. Use the same inflow and outflow lines each week so you can spot trends. If you need more detail, add a second tab rather than cluttering the main forecast. A stable structure makes the forecast easier to review in meetings.

Every week, replace last week's estimates with actuals and roll the sheet forward one week. Update invoices that were paid, deals that slipped, and new expenses. The discipline of weekly updates matters more than perfect precision. Patterns will emerge: certain clients always pay late, specific expenses spike mid-month, or payroll plus rent creates a predictable low point.

Reconcile the forecast with your bank balance weekly. If the forecast and bank are off, find the gap immediately. This keeps the model honest and prevents a slow drift away from reality.

Use color to flag risk. Highlight weeks where the projected ending cash drops below a threshold, maybe one month of payroll. When you see a dip coming, you have options: accelerate invoicing, ask for deposits, delay discretionary spend, or line up a short-term facility. The forecast becomes your early warning system rather than a post-mortem.

Scenario planning is optional but powerful. Create a copy of the sheet with conservative assumptions and another with aggressive assumptions. This shows how sensitive cash is to a delayed payment or a new hire. You do not need complex modeling to get value; two scenarios are enough to frame decisions.

Create an action playbook for red weeks. Decide in advance which levers you will pull first: collections sprint, expense freeze, deferred hiring, or financing outreach. When a dip appears, you will act faster and with less stress.

Share the forecast with a small leadership group. This creates accountability for collections, spend decisions, and sales timing.