Enter your cash balance, revenue, and expenses. Get your burn rate, cash runway, projected cash-out date, and a full 90-day forecast — in under 2 minutes.
Every formula is based on standard corporate finance methodology used by CFOs, the SBA, and professional lenders. No black boxes — every number is explained.
Net Cash Flow
Total Inflows − Total Outflows
$80,000 − $110,000 = −$30,000
Ending Cash Balance
Opening Cash + Net Cash Flow
$250,000 + (−$30,000) = $220,000
Burn Rate
Monthly Outflows − Monthly Inflows
$110,000 − $80,000 = $30,000/mo
Cash Runway
Current Cash ÷ Monthly Burn Rate
$250,000 ÷ $30,000 = 8.3 months
Fill in your current cash and your three months of expected revenues and expenses. The tool calculates your net cash flow, ending balance, burn rate, and runway.
Starting Position
Total cash across all business bank accounts right now
Get alerted when projected cash falls below this level (e.g. 1 month of expenses)
Forecast Scenario
Using your exact numbers as entered.
Month 1: May 2026
Cash Inflows
Cash actually expected to arrive in your bank this month
Cash Outflows
Software, insurance, utilities, marketing
Month 2: June 2026
Cash Inflows
Cash actually expected to arrive in your bank this month
Cash Outflows
Software, insurance, utilities, marketing
Month 3: July 2026
Cash Inflows
Cash actually expected to arrive in your bank this month
Cash Outflows
Software, insurance, utilities, marketing
Formulas: Net Cash Flow = Inflows − Outflows · Burn Rate = Avg Monthly Outflows − Avg Monthly Inflows · Runway = Cash ÷ Burn Rate
Your 90-day forecast will appear here
Fill in your numbers on the left and click Generate Forecast.
A real-world example using the formulas above. Use these numbers to verify the tool and understand how each metric is derived.
Company profile: Tech Services SMB — $250,000 current cash
Revenue: $80,000/month · Total expenses: $110,000/month · Burn rate: $30,000/month
| Month | Opening Cash | Inflows | Outflows | Net Flow | Ending Cash |
|---|---|---|---|---|---|
| Month 1 | $250,000 | $80,000 | $110,000 | −$30,000 | $220,000 |
| Month 2 | $220,000 | $80,000 | $110,000 | −$30,000 | $190,000 |
| Month 3 | $190,000 | $80,000 | $110,000 | −$30,000 | $160,000 |
| 90-Day Summary | $250,000 | $240,000 | $330,000 | −$90,000 | $160,000 |
Burn Rate
$30,000/month
$110,000 − $80,000
Cash Runway
8.3 months
$250,000 ÷ $30,000
Projected Cash-Out
~Feb 12, 2027
8.3 months from today
How InvoiceFollowUps.com stacks up against Float, Pulse, Dryrun, QuickBooks, and Xero for cash flow forecasting.
| Tool | Free | Forecast Period | Scenarios | Burn Rate | Runway | Alerts | Best For |
|---|---|---|---|---|---|---|---|
| InvoiceFollowUps.comYou are here | Full free tool | 90-day / monthly | SMBs, startups, CFOs | ||||
| Float | 14-day trial | 13-week / daily | Mid-market finance teams | ||||
| Pulse | 30-day trial | Monthly | Small businesses | ||||
| Dryrun | 14-day trial | 90-day / weekly | Accountants, advisors | ||||
| QuickBooks Planner | Included in QB | 90-day | Existing QB users | ||||
| Xero Forecast | Included in Xero | Monthly | Existing Xero users |
Table based on publicly available feature pages as of May 2025. Features may change; verify with each provider.
A 90-day cash flow forecast is a financial model that shows exactly how much cash your business will have at the end of each week or month over the next three months. Unlike a profit and loss statement — which shows revenue minus expenses on an accrual basis — a cash flow forecast shows actual dollars in your bank account on specific future dates.
According to a U.S. Bank study, 82% of small business failures are caused by poor cash flow management — not by a lack of profitability. A business can report strong profits on its P&L and still miss payroll next Tuesday. Cash flow forecasting eliminates that blindspot.
The 90-day horizon — also called a rolling 90-day forecast or 13-week cash flow forecast when done weekly — is the standard timeframe recommended by the SBA, financial advisors, and lenders for operational liquidity planning. It's long enough to reveal seasonal gaps and short enough to be meaningfully accurate.
A 13-week cash flow forecast and a 90-day forecast cover the same period — the difference is granularity. A 13-week forecast shows weekly cash positions (used by CFOs, lenders, and companies in financial distress). A monthly 90-day forecast is better for healthy growing businesses doing strategic planning.
13-Week (Weekly) — Choose if:
90-Day Monthly — Choose if:
Burn rate is the net amount of cash your business consumes each month. The formula is straightforward:
A burn rate of $30,000/month means your business needs $30,000 more than it's bringing in each month. To reduce burn rate without cutting headcount, start with the highest-leverage levers: accelerate invoice collections (every 10 days faster = significant cash freed), renegotiate vendor payment terms, and defer discretionary software subscriptions.
Cash runway is the number of months before cash hits zero: Current Cash ÷ Burn Rate. Most investors expect 12–18 months of runway. Below 6 months — fundraising takes 3–6 months to close — you're in the danger zone.
A rolling cash flow forecast is updated continuously as actual data comes in. Each week, you add one new week (or month) to the end and drop the oldest period — keeping you always 90 days ahead. Here's how to build one:
Start with your actual bank balance
Pull the real figure from your bank account — not your accounting system's balance, which may include uncollected checks or unrealized revenue.
Map confirmed inflows from your AR aging
Go line by line through your accounts receivable aging report. An invoice 30 days overdue has a very different collection probability than one due next week.
List all fixed outflows first
Payroll, rent, loan payments, and insurance are non-negotiable and highly predictable. Enter these exactly.
Estimate variable expenses conservatively
For costs that fluctuate (inventory, contractor spend, marketing), use your 3-month historical average and add 10–15% for surprises.
Update weekly against actuals
Every Monday, reconcile projected vs. actual and roll the forecast forward. A forecast not updated with real data is fiction.
The #1 Cash Flow Mistake Small Businesses Make
Confusing invoiced revenue with collected cash. You can invoice $100,000 in a month and collect $40,000. Your cash flow forecast must use collection dates — not invoice dates. If your customers pay in 45 days, your Month 1 inflows are your Month −1 invoices, not your Month 1 invoices.
→ Calculate how much cash your slow-paying customers are holding hostageAuthored by: InvoiceFollowUps.com Finance Research Team
Last Updated: May 10, 2025
Formulas: Net Cash Flow = Total Inflows − Total Outflows · Ending Cash = Opening Cash + Net Cash Flow · Burn Rate = Avg Monthly Outflows − Avg Monthly Inflows · Cash Runway = Current Cash ÷ Monthly Burn Rate
Scenario Planning: Best case applies +20% to revenue and −10% to expenses. Worst case applies −30% to revenue and +15% to expenses. These ranges are consistent with standard financial stress-testing methodology used by CFOs and lenders.
Sources: AICPA cash flow projection standards · SBA cash flow planning guidelines · SEC disclosure requirements for liquidity and capital resources · Standard corporate finance textbook methodology (Berk & DeMarzo, Corporate Finance, 5th ed.)
Limitations: This tool uses user-entered estimates. It does not import bank data or accounting system data automatically. Update inputs with actual figures weekly for best accuracy. All results are estimates for planning purposes only.
The businesses that survive cash crunches are the ones that see them coming 90 days in advance. Build your forecast now — it takes under 2 minutes.
Working Capital Requirement Calculator
See exactly how much cash your slow-paying customers are holding hostage.
ToolCash Flow Gap Calculator
Find the exact gap between what you invoice and when you collect.
GuideHow to Avoid Running Out of Cash
The 7 actions CFOs take to extend runway without raising capital.
Guide13-Week Cash Flow Forecast: Complete Guide
When and how to build a weekly rolling forecast — with a free template.
External ↗SBA Cash Flow Management Guide
Official SBA guidance on cash flow projections for small businesses.
External ↗AICPA Projections & Forecasts Standards
Professional accounting standards for financial projections (AT-C 305).
Methodology & Attribution
Authored by: InvoiceFollowUps.com Finance Research Team
Calculation Method: Standard corporate finance cash flow projection methodology. Net Cash Flow = Total Inflows − Total Outflows. Burn Rate = Avg Monthly Outflows − Avg Monthly Inflows. Cash Runway = Current Cash ÷ Monthly Burn Rate (per AICPA AT-C 305 financial projections guidance).
Scenario Multipliers: Best case: +20% revenue, −10% expenses. Worst case: −30% revenue, +15% expenses. Based on typical variance ranges from CFO Alliance benchmarking data.
Last Updated: May 10, 2025
Sources: SBA.gov ↗, AICPA.org ↗, SEC.gov ↗, Berk & DeMarzo, Corporate Finance (5th ed.)
Disclaimer: All results are estimates for financial planning purposes only. Not a substitute for professional accounting advice. Update inputs weekly with actual bank data for best accuracy.