Cash Flow Forecasting for Small Businesses: A Simple 5 Step Framework

Here’s something that surprises a lot of business owners: you can be profitable and still run out of cash.

Profit is what your P&L says you earned. Cash is what’s actually in the bank. They’re not the same, because customers pay late, bills come due early, and loan payments and taxes don’t show up on your P&L the way you’d expect.

A cash flow forecast closes that gap. It tells you what’s coming before it gets here. And it doesn’t need to be complicated.

What you’ll need

• Your current bank balance(s)

• A list of who owes you money and when you expect it (your AR)

• A list of bills you owe and when they’re due (your AP)

• Payroll dates and amounts

• Fixed payments: rent, loans, insurance, subscriptions

• Estimated tax payments

The 5‑step framework

Step 1: Start with cash today. Not what QuickBooks says you’ll have. What’s actually in the bank right now.

Step 2: List the cash coming in, week by week. Use when you realistically expect to get paid, not the invoice due date. If a customer always pays 20 days late, plan for 20 days late.

Step 3: List the cash going out, week by week. Payroll, rent, loan payments, vendor bills, credit card payments, taxes. Big once‑a‑year items too, like insurance renewals.

Step 4: Roll it forward 13 weeks. Each week: starting cash, plus cash in, minus cash out, equals ending cash. That ending cash becomes next week’s starting cash. Thirteen weeks is about a quarter, which is far enough out to see trouble coming and close enough to be accurate.

Step 5: Compare actual to forecast every week. Where were you off? Customers paid slower? A bill you forgot? This is how the forecast gets more accurate, and how you learn your business’s real patterns.

What to look for

• Any week where cash dips below your comfort level. That’s your early warning. Now you have weeks, not days, to fix it.

• Big swings. Payroll weeks and loan payment weeks often line up in ways that hurt.

• Slow payers. If AR is always later than you plan, that’s a collections problem, not a cash problem.

How often to update it

Weekly is ideal. It only takes 20 to 30 minutes once it’s set up. If weekly feels like too much, every two weeks still beats not doing it at all.

A simple spreadsheet is fine

You don’t need special software. A spreadsheet with weeks across the top and cash in and cash out down the side does the job. What matters is that you update it and actually look at it.

Want help building yours?

If cash always feels tight and you’re not sure why, a forecast is usually the first thing I build as a fractional CFO for a new client. Book 30 minutes with me and we’ll start there.

— Kari