What Is Cash Flow? Definition

What is cash flow?

Cash flow is the movement of money into and out of your business over a specific period. For professional service firms, positive cash flow means more money coming in (client payments, loan proceeds) than going out (payroll, vendors, taxes, rent). Negative cash flow means burning more cash than generating. Cash flow differs from profit: a firm can be profitable on paper while running out of money if clients pay slowly (high AR) or if investing heavily in growth (new hires, marketing spend). Managing cash flow means ensuring enough cash on hand to meet obligations while optimizing the timing of inflows and outflows.

Numetix is the expert-led, AI-powered, human-in-the-loop bookkeeping layer that tracks cash weekly and reconciles every account, so the cash you see is the cash you have.

Key characteristics of cash flow

Three types: Operating (client payments, expenses), Investing (equipment, acquisitions), Financing (loans, owner contributions)
Measured weekly, monthly, or quarterly, depending on business volatility
Key metric: cash runway (months of cash remaining at current burn rate)
Affected by payment terms: Net 30 clients pay faster than Net 60
Seasonal: consulting firms often see Q4 slowdowns, Q1 surges.

Why cash flow matters for service firms

Cash flow problems kill profitable businesses. A consulting firm with $2M revenue and $300,000 profit can fail if $500,000 sits in AR while $400,000 in payroll and expenses come due. Understanding cash flow timing prevents emergency scrambles for credit lines or personal loans. A firm growing from $2M to $4M revenue needs $150,000-$300,000 in additional working capital to fund the AR growth, even if highly profitable. Forecasting cash flow 90 days ahead enables confident hiring decisions instead of reactive layoffs.

Example: Monthly cash flow for a growing consulting firm

Beginning cash: $180,000
Cash inflows:
Client payments collected: $320,000
Line of credit draw: $50,000
Total inflows: $370,000

Cash outflows:
Payroll (2 cycles): $185,000
Contractor payments: $42,000
Vendor bills: $38,000
Rent & utilities: $12,000
Marketing spend: $18,000
Loan payment: $8,000
Owner draw: $15,000
Total outflows: $318,000
Ending cash: $232,000 (+$52,000 vs beginning)
Cash runway: 8.8 months at current burn rate

Note: Generated $48,000 profit this month, but cash only grew $52,000 due to AR collections timing

Frequently asked questions

What is the difference between cash flow and profit?

Profit is revenue minus expenses on an accrual basis, while cash flow is the actual movement of money. Slow-paying clients, large purchases, or loan repayments can leave a profitable firm short of cash, so it pays to watch both.

What are the three types of cash flow?

Operating cash flow comes from day-to-day business, investing cash flow comes from buying or selling long-term assets, and financing cash flow comes from loans and owner contributions. The cash flow statement reports each one separately.

Cash flow