Cash Flow Calculator

Cash Flow Calculator

A business can be profitable on paper and still run out of money. Cash flow and profit measure different things — profit counts revenue when it is earned, while cash flow counts money when it actually arrives. Many small businesses fail not because they lose customers but because they run short of cash while waiting for invoices to be paid. This calculator tracks actual inflows and outflows to show net cash flow, operating cash flow, and free cash flow for any period.

How Cash Flow Is Calculated

Cash flow analysis is built on four formulas:

• Net Cash Flow = Total Cash Inflows - Total Cash Outflows
• Operating Cash Flow (OCF) = Revenue Collected - Operating Expenses Paid
• Free Cash Flow (FCF) = Operating Cash Flow - Capital Expenditures
• Ending Cash Balance = Beginning Cash Balance + Net Cash Flow

Free cash flow is what remains after maintaining and expanding the business — it is the figure that drives dividends, debt paydown, and reinvestment decisions.

Worked Examples

Example 1 — Positive operating cash flow, constrained free cash flow A contractor collects $80,000 in a month, pays $55,000 in labor and materials, and buys a $22,000 piece of equipment. OCF = $80,000 - $55,000 = $25,000. FCF = $25,000 - $22,000 = $3,000. Despite healthy operations, only $3,000 is freely available that month.

Example 2 — Profitable but cash-flow negative month A consulting firm books $90,000 in revenue in March but collects only $60,000 (the rest is outstanding invoices on Net 30 terms). Operating expenses paid are $65,000. OCF = $60,000 - $65,000 = -$5,000. The firm is profitable on its income statement but has a $5,000 cash shortfall this month.

Example 3 — Three-month forecast A retail shop starts Q2 with $18,000 cash. Month 1: +$7,000 net cash flow. Month 2: -$4,000 (inventory build for summer). Month 3: +$12,000 (summer sales). Ending balance after Q2: $18,000 + $7,000 - $4,000 + $12,000 = $33,000. The dip in Month 2 is manageable if the business knew to expect it — but would trigger a bank call if it arrived as a surprise.

Cash Flow Reference Table

When to Use

• Building a 90-day or 13-week rolling cash flow forecast to spot shortfalls before they arrive
• Evaluating whether a planned equipment purchase or expansion will leave sufficient cash to cover operations
• Diagnosing why a profitable business keeps running low on cash — identifying whether the cause is receivables timing, inventory buildup, or debt service
• Preparing for a bank loan or line of credit application where the lender will examine cash flow history
• Comparing operating cash flow across periods to assess whether the core business is generating more or less cash over time independent of financing activity

Common Mistakes

1. Conflating profit with cash — if customers pay on Net 30 or Net 60 terms, you can book months of revenue without receiving cash; a cash flow analysis uses only collected amounts, not invoiced amounts.
2. Omitting loan principal repayments — principal payments reduce cash but are not an expense on the income statement; leaving them out of a cash flow projection overstates available cash by the entire repayment amount.
3. Treating a single positive month as the full picture — one strong month can mask a structural problem; look at 3-6 months together to distinguish a seasonal peak from a genuine improvement.
4. Ignoring the timing of large, irregular outflows — annual insurance premiums, quarterly tax deposits, and seasonal inventory buys hit in specific months; missing these from a forecast produces misleadingly optimistic cash balances for the other months.

Real-World Applications

During the 2020 COVID-19 disruptions and again during the 2022-2023 inflation surge, cash flow management separated surviving businesses from those that closed. Many firms that had been profitable for years found their cash reserves depleted within 60-90 days when revenue dropped suddenly. The U.S. Small Business Administration and SCORE both reported that cash flow mismanagement — not lack of profitability — was the leading cause of small business failure cited by closed businesses. Companies that maintained rolling cash flow forecasts were better positioned to draw on lines of credit proactively, defer non-essential capital spending, and negotiate extended terms with suppliers.

Tips

• Keep a minimum cash buffer equal to 2-3 months of fixed operating expenses — this covers payroll and rent through a revenue gap without requiring emergency financing
• Build a rolling 13-week forecast and update it every Monday with the prior week’s actual inflows and outflows — this gives you a 90-day view that moves with you
• Shorten your collections cycle by switching from Net 30 to Net 15 on new invoices or offering a 2% early payment discount (2/10 Net 30) — even partial adoption can free weeks of working capital
• Separate capital expenditures from operating expenses in your tracking so you can see operating cash flow clearly and make informed decisions about whether a CapEx purchase is truly affordable that period
• For seasonal businesses, build a 12-month annual forecast and identify the 2-3 months where cash is naturally thinnest — then arrange a credit line or set aside reserves during peak months specifically to cover those troughs
• Review your three cash flow categories — operating, investing, and financing — each quarter; a business with consistently negative operating cash flow that only looks solvent because of new loans or asset sales has a structural problem that compound interest will eventually make worse