Cash Flow Calculator — Monthly Forecast & Runway

Profit is opinion. Cash is fact. Many profitable businesses have failed because they ran out of cash. The Cash Flow Calculator forecasts your monthly net cash, projected closing balance, and — if you’re burning — how many months of runway remain. Use it weekly. It’s the most important spreadsheet you’ll ever build.

Cash Flow Calculator

Forecast monthly cash flow, runway, and closing balance — the survival metric for any business.

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Cash Inflows (per month)

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Cash Outflows (per month)

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Cash Flow Forecast

Net Monthly Cash Flow–
Total Inflows (period)–
Total Outflows (period)–
Closing Balance–
Cash Runway (if negative)–
Status–

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Cash Flow vs Profit

A business can be profitable on paper (P&L) and still bankrupt in cash. Why? Customers haven’t paid yet (receivables), inventory is sitting unsold (working capital), or capex was huge but spread as depreciation (so it “hides” in the P&L).

Cash flow is the actual movement of money in and out of your bank account. If cash flow stays negative for too long, no amount of accounting profit can save you.

The Three Cash-Flow Buckets

  • Operating cash flow: from running the business — sales receipts minus COGS, salaries, rent, opex, taxes.
  • Investing cash flow: capex, asset purchases/sales, business acquisitions.
  • Financing cash flow: loans taken/repaid, equity raised, dividends paid.

This calculator focuses on operating cash flow plus debt service (loan EMIs and taxes) — the cash that determines day-to-day survival.

Worked Example

Example: Opening cash $50,000. Monthly inflows: sales $80,000 + other $2,000 = $82,000. Monthly outflows: COGS $40,000, salaries $20,000, rent $5,000, opex $6,000, EMI $3,000, taxes $2,000 = $76,000. Net monthly cash flow = +$6,000. Closing balance after 12 months = $50,000 + $72,000 = $122,000. Healthy.
Example: Now imagine inflows drop to $60,000 (recession). Outflows stay at $76,000. Burn = −$16,000/month. Runway = $50,000 / $16,000 = 3.1 months. Time to cut costs or raise capital.

Cash Flow Survival Tactics

  • Shorten receivables — invoice immediately, offer 1–2% early-pay discounts, charge deposit upfront.
  • Lengthen payables — negotiate 60–90 day terms with suppliers without abusing the relationship.
  • Reduce inventory — every dollar in stock is a dollar not in your bank.
  • Subscriptions / retainers — convert one-off projects into recurring revenue.
  • Maintain 3–6 months of runway in cash at all times. Survivable shocks happen.

Frequently Asked Questions

Why is cash flow more important than profit?▾
Profit is an accrual measure — recorded when earned, not when received. Cash flow is when money actually moves. A company can be highly profitable but unable to pay rent if customers haven’t paid yet.
How often should I forecast cash flow?▾
Weekly for early-stage startups and any business with <6 months of runway. Monthly for stable businesses. Quarterly only for very mature, predictable businesses.
What’s a healthy cash flow margin?▾
Operating cash flow / revenue should be 10–20% for most businesses; 25%+ for software/SaaS; 5–10% for thin-margin retail.
How do I include seasonality?▾
Build the forecast month by month rather than averaging. Seasonal businesses (retail in December, restaurants in summer) can have positive annual cash flow but multi-month dips that bankrupt them if not planned.

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