Profit is what your accountant talks about. Cash flow is what keeps you in business. The two are not the same thing, and confusing them is one of the most dangerous mistakes a small business owner can make.
A business can be genuinely profitable on paper while simultaneously running out of money in its bank account. This is not a theoretical problem. It is the reality that causes roughly half of small business failures. A cash flow forecast is the tool that lets you see that situation coming before it becomes a crisis.
This guide explains the difference between profit and cash flow, how to build a 12-month forecast, what warning signs to look for, and practical ways to improve your cash position. Use the Cash Flow Forecast tool to model your own numbers.
Profit vs Cash Flow: Why They Are Different
Here is a concrete example that illustrates the problem.
You run a small B2B services business. In March, you deliver £30,000 worth of work. You invoice your clients on net 60 terms, which means they will pay in May. Your business expenses in March (salaries, rent, software, utilities) total £22,000. On paper, you made £8,000 profit in March.
But in March, the cash coming into your bank account is not £30,000. It is the payment from January's invoices, which might be £25,000. Meanwhile, you have to pay March's £22,000 in expenses. You also have a £10,000 VAT bill due, and a £5,000 corporation tax instalment.
Your bank balance in March goes down, even though you are profitable. If you did not see that coming, you might find yourself unable to make payroll or missing a supplier payment.
This is why profit and cash flow are tracked separately. Profit is a measure of business performance. Cash flow is a measure of survival.
The Three Cash Flow Categories
Cash flow in a business comes from three distinct sources, and a proper analysis separates them.
Operating cash flow. The cash generated (or consumed) by your day-to-day business operations. Revenue collected from customers minus expenses paid to suppliers, employees, HMRC, and others. This is the most important category for most small businesses.
Investing cash flow. Cash used to buy or sold from selling long-term assets: equipment, vehicles, property, software licences, or other capital investments. When you spend £15,000 on a new machine, that appears as negative investing cash flow. It does not appear in your profit and loss account immediately; instead, it is depreciated over several years.
Financing cash flow. Cash from borrowing (loans, credit facilities) or from equity (investment from shareholders), minus repayments of debt or dividends paid to shareholders. If you take out a £20,000 business loan, that is positive financing cash flow. Your monthly repayments are negative financing cash flow.
For a simple small business forecast, you can combine these into a single monthly view, but understanding the distinction helps you interpret what is driving your cash position.
How to Build a 12-Month Cash Flow Forecast
A cash flow forecast has three components for each month: opening balance, cash in, and cash out. The closing balance of one month becomes the opening balance of the next.
Step 1: Start with your opening balance. This is the cash in your bank account right now (or at the start of your forecast period). Include all business accounts.
Step 2: Forecast cash in each month. This is money you expect to actually receive in that month, not money you have invoiced. The key question is: when will you collect it?
List your expected income sources: client payments, product sales, grant receipts, loan drawdowns. Apply your payment terms realistically. If 30% of your clients pay late by an average of 2 weeks, build that into your estimates rather than assuming everyone pays on time.
If your income is seasonal or lumpy, reflect that. Do not just divide annual revenue by 12 and spread it evenly.
Step 3: Forecast cash out each month. List everything you expect to pay: payroll, rent, supplier invoices, loan repayments, HMRC payments (VAT, PAYE, corporation tax), insurance, subscriptions, professional fees, and any planned capital expenditure.
Be specific about timing. Your VAT return might be quarterly rather than monthly. Corporation tax is typically paid in a lump sum (9 months after your financial year end for smaller companies). Annual subscriptions and insurance renewals create spikes.
Step 4: Calculate closing balance. Opening balance + cash in - cash out = closing balance. Any month with a negative closing balance is a problem you need to plan for.
Step 5: Review and stress-test. What happens if one major client pays 30 days late? What if sales in month 3 are 25% lower than forecast? Run a downside scenario and check whether you have sufficient buffer.
Reading the Warning Signs
When you look at your completed 12-month forecast, certain patterns should prompt action.
Months with a negative closing balance. These are cash crises waiting to happen. You need either to increase cash in (collect faster, sell more), reduce cash out (defer spending, negotiate supplier terms), or arrange a credit facility before you need it.
A steadily declining balance. Even if you never go negative, a balance that falls month after month indicates that outgoings are consistently exceeding receipts. This is a structural problem that will eventually become a crisis.
High dependence on a single large payment. If your forecast shows a healthy balance in month 6 primarily because one large client is expected to pay then, you are exposed to significant risk. Late payment from that client turns a comfortable month into a crisis.
Seasonal troughs you have not prepared for. Many businesses have predictable slow periods. If you have not factored in the reduced revenue during those months, your forecast will not reflect the reality you face.
HMRC spikes. VAT bills, PAYE settlements, and corporation tax payments are predictable and large. Many business owners are surprised by them because they have not planned ahead. They should never surprise you once you have a forecast.
Strategies to Improve Cash Flow
Once you can see where the gaps are, you have options for addressing them.
Invoice promptly. Every day you delay invoicing after completing work is a day added to when you will receive payment. Invoice on the day the work is delivered or the milestone is reached. Do not batch invoices at month end.
Shorten payment terms. If you currently offer Net 30, consider moving to Net 14 for new clients. Existing clients may resist change, but for new relationships, shorter terms can be set from the start.
Offer early payment discounts. A 1-2% discount for payment within 7 days is worth considering if cash flow is tight. The cost of the discount is often less than the cost of the overdraft you would otherwise use to bridge the gap.
Chase late payments systematically. Have a defined process: an automatic reminder the day after the due date, a phone call at day 7, a formal notice at day 14. Many clients pay late simply because no one chases them.
Negotiate supplier payment terms. Just as clients pay you, you pay suppliers. Ask for longer terms where possible. Moving from Net 14 to Net 30 with your main suppliers frees up working capital without costing you anything.
Maintain a credit facility before you need it. Banks are more willing to arrange an overdraft or credit line when you do not urgently need one. Set it up when your business is performing well so it is available when you need it.
Defer non-essential spending. If the forecast shows a cash crunch in month 4, review what spending can be moved to month 5 or 6. Capital expenditure, marketing campaigns, and hiring decisions can often be timed around cash flow rather than driven by them.
Consider invoice finance. If you have large outstanding invoices and need cash now, invoice finance lets you access 80-90% of the invoice value immediately, with the remainder (minus fees) paid when the client pays. It is not cheap, but it can bridge a significant gap.
The Relationship Between Cash Flow and Profit
Understanding why cash flow and profit diverge helps you build a more accurate forecast.
Accrual accounting vs cash accounting. Most businesses use accrual accounting, where revenue is recognised when it is earned, not when it is received. Profit in your accounts reflects invoiced revenue. Cash flow reflects collected revenue.
Capital expenditure. When you buy equipment, it leaves your bank account immediately as negative cash flow. But it appears in your profit and loss account gradually, as depreciation over several years. The cash impact hits first and hard.
Loans and repayments. A loan gives you a cash inflow that does not appear in your profit and loss at all (it is a liability, not revenue). Loan repayments are a cash outflow that does not appear as a cost in P&L (only the interest element is an expense; the principal repayment reduces the liability).
Tax timing. You might owe corporation tax on profits from last year, paid this year. That is a cash outflow this year, but it was a cost in last year's accounts.
These timing differences are why profit and cash can look very different in any given month.
Getting Started
A cash flow forecast does not need to be a complex spreadsheet. At its core, it is a list of expected receipts and payments for each of the next 12 months, starting from your current bank balance.
Start rough. An imperfect forecast made today is infinitely more useful than a perfect one never made. Revisit it monthly, update actuals, and roll it forward. Over time, you will get better at estimating both income and outgoings, and the forecast will become a reliable early warning system.
The Cash Flow Forecast tool lets you input your current balance, expected monthly receipts, and expected monthly payments, then see your projected closing balance for each month. Start there and build the habit of checking it regularly.