How to Create a Cash Flow Forecast for Your Small Business

How to create a cash flow forecast for your small business (without an accountant on retainer)

You can be profitable on paper and still miss payroll. I've watched it happen to a client of mine — a bakery doing €38,000 a month in revenue, profitable by every accounting measure, and one Friday afternoon she couldn't cover the flour delivery. The profit was real. The cash wasn't there yet. That gap is exactly what a cash flow forecast is built to catch, and it's the single exercise that separates business owners who sleep at night from those refreshing their bank app at 11pm.

Here's the honest problem: most small business owners I've worked with run their finances on a feeling. Revenue looks fine, so they assume cash is fine. Then a big supplier invoice lands on the same week as the quarterly VAT payment and suddenly it's a crisis. A cash flow forecast fixes this. Not because it's clever, but because it forces you to write down what you actually expect to happen, in order, with dates attached.

What a cash flow forecast actually tracks (and why profit misleads you)

Profit is an opinion about timing. Cash is a fact about timing.

When you invoice a client for €10,000 with 30-day payment terms, your accounting software books that revenue today. Your bank account sees nothing for a month — or, in my experience, closer to 45 days, because the "30-day" term is a polite fiction. I tracked one year of my own invoicing and found my average collection time was 41 days against stated 30-day terms. That eleven-day gap is where small businesses die.

A cash flow forecast ignores the question "did I earn it?" and answers a narrower, more useful one: on which specific date will this money hit my account, and on which dates will money leave it?

Direct or indirect method — which one should you use?

You'll see two approaches. The direct method lists every actual receipt and payment: client A pays €4,000 on the 12th, rent leaves on the 1st, supplier invoice clears on the 20th. The indirect method starts from net profit and adjusts for non-cash items and working capital changes.

Use the direct method. Always. Unless you're producing statutory accounts for a lender, the indirect method is useless for day-to-day decisions — it tells you what already happened, framed in accounting language, and it hides the exact detail you need. I've seen indirect-method forecasts that were technically correct and completely useless for deciding whether to hire someone in March.

What never goes in a cash flow forecast

This trips people up constantly. Depreciation, amortisation, bad debt provisions, accrued but unpaid expenses — none of these belong in a cash flow forecast. They're accounting constructs. If the money didn't move, it doesn't go in the sheet.

What does go in, and what most templates forget:

• VAT collected on sales, and the date it leaves your account (not the date you made the sale)
• Payroll taxes and social contributions, which usually clear a different day than the wages themselves
• Corporation tax and any quarterly instalments
• Loan repayments split into interest and principal — the principal portion still leaves your bank
• Owner's drawings, if you're a sole trader
• Equipment purchases, even small ones paid on a card

Building your forecast, step by step

Here's the process I use, refined over a decade of doing this badly before doing it well.

Step 1: pick your period and horizon

Two forecasts, running in parallel:

• 13-week rolling forecast, weekly columns. This is your early warning system. Weekly resolution catches problems while you still have options.
• 12-month forecast, monthly columns. This is your planning view — hiring, equipment, seasonal swings.

Why 13 weeks? Because it's roughly a quarter, it's long enough to see a problem coming, and short enough that you can forecast with reasonable confidence. Anything past three months is guesswork dressed up as precision.

Step 2: set up your columns properly

Most free templates online get this wrong. They mix cash and accrual concepts, or they lump all outflows into one column. Here's what actually works:

Column	What goes in it	Why it matters
Week / Month	Date range	Every row needs a date anchor
Opening cash	Bank balance at period start	Your starting point, always reconciled to the bank
Customer receipts	Cash actually expected in	Segmented by payment behaviour, not by invoice date
Other inflows	Loans, grants, asset sales	Keep separate so you don't rely on them
Supplier payments	Actual payment dates	What you pay, when you pay it
Payroll + taxes	Wages, social charges, PAYE	Usually the largest single line
Fixed costs	Rent, insurance, subscriptions	Predictable, so get them right
VAT / tax payments	Actual due dates	Lumpy and dangerous if ignored
Closing cash	Opening + inflows − outflows	The number you're actually managing

Step 3: forecast collections realistically, not hopefully

This is where forecasts fail. Owners forecast collections based on payment terms. Reality is messier.

Go through your last six months of invoices and work out your actual collection pattern. For me it looked like this: 40% of clients paid within terms, 35% paid a week or two late, 15% paid a month late, and 10% needed chasing twice. I built those percentages into my forecast and my cash projections stopped lying to me.

If you don't have six months of data yet, be conservative. Assume your slowest-paying client's behaviour across your whole book. You'll be wrong, but you'll be wrong in the safe direction.

Step 4: build three scenarios, not one

A single forecast is a prediction. Three scenarios are a decision-making tool.

1. Realistic case: your normal collection pattern, normal sales, no surprises.
2. Pessimistic case: your two biggest clients pay 30 days late, sales dip 20%, and one unexpected cost hits.
3. Optimistic case: everything lands on time and you close a deal you're hopeful about.

The pessimistic case is the one you act on. If your pessimistic forecast shows you going negative in week 9, you have seven weeks to arrange a credit line, chase receivables, or delay a purchase. That's the entire point.

Step 5: identify your cash runway and alert thresholds

Two numbers every owner should know:

Net burn rate: if you're spending more than you're bringing in, how much are you burning per month? Take your total outflows minus inflows over the last three months, divide by three.

Cash runway: current cash divided by net burn. If you have €45,000 in the bank and you're burning €9,000 a month, you have five months. That's your deadline for fixing the problem.

For a business that's already cash-positive, set a floor instead. I keep a minimum of two months' operating costs as a hard floor — if my forecast dips below it, I stop discretionary spending that same week. You'll pick your own number, but pick one. A floor you've written down is a decision. A floor in your head is a hope.

Tools, templates, and what they actually cost you

You do not need software to do this. I ran my first forecasts in a spreadsheet with nine columns and a formula I copied down 52 rows. It worked fine.

Approach	Best for	Realistic setup time	Weakness
Excel / Google Sheets template	Most small businesses under €1M revenue	2–3 hours	Manual updates, breaks if formulas get mangled
Bank-connected tool	Businesses with high transaction volume	1 hour to connect, ongoing sync	Monthly cost, and it still can't see invoices you haven't issued
Accounting software module	Anyone already using the software daily	Depends on setup	Often mixes accrual and cash views if misconfigured

The spreadsheet wins for most people. Download a template, delete half the rows you don't need, and adjust the categories to match your actual business. A cash flow forecast that reflects someone else's business is worse than useless — it's misleading.

Whichever route you pick, the update cadence matters more than the tool. Once a month at minimum. Weekly if cash is tight. I'll admit I let mine go stale for two months during a busy stretch once, and I missed a VAT payment date I'd have caught immediately with a glance. Cost me a late penalty and a very unpleasant phone call.

The mistakes that break forecasts

I've made all of these. Learn from my bruises.

Forecasting revenue instead of collections. The most common error by a wide margin. Your forecast needs payment dates, not invoice dates.

Forgetting the lumpy stuff. Annual insurance, quarterly VAT, corporation tax instalments, that one subscription that renews every March. These are the payments that blow up an otherwise healthy month.

Building one scenario and treating it as truth. You will be wrong. Plan for being wrong in both directions.

Never reconciling to the bank. If your opening cash figure doesn't match your actual bank balance, everything downstream is fiction. Reconcile first, forecast second.

Making it too complicated. A 40-line forecast you never update is worse than a 12-line forecast you check every Monday. Start simple. Add detail only when a specific problem demands it.

What to do this week

Open a spreadsheet. Put today's bank balance in the first cell. List your expected inflows for the next 13 weeks with dates attached, using your real collection history rather than your payment terms. Do the same for outflows. Subtract. Look at the lowest number in your closing cash row.

That number is the most useful thing you'll learn about your business this month. If it's comfortably positive, you've bought yourself peace of mind for the price of an afternoon. If it's negative, you just found out early — which is the only advantage that matters.

The forecast won't be accurate. Mine never is, not in the details. But it's accurate enough to see the wall before you hit it, and that's the whole game. The owners who survive the lean quarters aren't the ones with better instincts. They're the ones who wrote the numbers down and looked at them honestly.