Cash Flow Runway Calculator

{{ riskLabel }} {{ netBurnBadge }} {{ reserveBadge }} {{ forecast_months }} month view

Use cash expected to hit the bank, not invoice revenue. This model provides planning signals only and does not replace accounting records.

Business profile:

Choose a starting pattern for common small-business cash pressure cases.

Currency symbol:

Use $, €, £, RM, or another short symbol used in your internal cash forecast.

Current cash balance:

Enter the bank cash you can use for operations now.

Monthly cash inflow:

Use recent average collected cash or a conservative next-month forecast.

Receivables due soon:

Include invoices already issued and expected in the next one to three months.

Average collection delay: {{ collection_delay_days }} days

Use 0-90 days based on customer payment timing.

Monthly fixed outflow:

Exclude payroll and variable outflows entered below.

Payroll and contractor outflow:

Enter the normal monthly cash cost for staff and contractors.

Monthly variable outflow:

Use a recent average or a conservative next-month cash spend.

Monthly inflow growth: {{ formatPercent(inflow_growth_pct, 1) }}

Use -20% to 30%; keep it conservative for survival planning.

Monthly outflow growth: {{ formatPercent(outflow_growth_pct, 1) }}

Use 0 for steady spend, or a positive value for inflation, hiring, or vendor increases.

Safety cash floor:

Set the balance that triggers funding, expense cuts, or collection action.

Forecast horizon:

Use 13 weeks to 12 months for tactical cash control, or 18-36 months for planning.

Forecast start month:

Use the first month covered by your current bank balance.

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Payable timing delay: {{ payable_delay_days }} days

Use 0-30 days for agreed payment timing changes.

Planned funding or owner injection:

Enter 0 if no funding is committed; scenario rows still estimate the gap.

Funding month:

Month 1 is the forecast start month.

Expense cut scenario: {{ formatPercent(expense_cut_pct, 1) }}

Use a realistic cost-cut target for the next management review.

Inflow upside scenario: {{ formatPercent(revenue_upside_pct, 1) }}

Use 0 if there is no credible growth lever.

Receivable stress delay: {{ stress_delay_days }} days

Models slow customer payments in the stress scenario.

Bridge target:

Set the target period for the computed funding gap scenario.

Money precision:

Whole dollars are usually best for management review.

Metric	Value	Planning note	Copy
{{ row.metric }}	{{ row.value }}	{{ row.note }}

Month	Beginning cash	Cash in	Cash out	Ending cash	Signal	Copy
{{ row.month }}	{{ row.beginning }}	{{ row.cashIn }}	{{ row.cashOut }}	{{ row.ending }}	{{ row.signal }}

Scenario	Runway	Zero date	Ending cash	Operating move	Copy
{{ row.scenario }}	{{ row.runway }}	{{ row.zeroDate }}	{{ row.endingCash }}	{{ row.move }}

Trigger	Status	Action	Owner cue	Copy
{{ row.trigger }}	{{ row.status }}	{{ row.action }}	{{ row.ownerCue }}

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Cash pressure usually appears before a business is formally out of money. Payroll, rent, supplier terms, tax dates, inventory buys, and customer collection delays can make a company feel squeezed even while invoices and sales reports look healthy. Cash runway gives that pressure a calendar shape by asking how long usable cash can cover operating outflows before the balance reaches zero or a chosen reserve floor.

The useful runway number is based on cash movement, not accounting profit. A paid subscription, a signed purchase order, or a booked invoice may improve revenue, but it does not pay staff until money reaches the bank. The opposite can also happen when a seasonal business has strong cash after a busy month but faces a long stretch of fixed costs before sales recover.

Common cash runway terms and why they matter
Term	Plain meaning	Runway effect
Opening cash	Spendable operating cash already available	Sets the starting height of the runway.
Collected cash	Money expected to arrive in the bank	Extends runway only when timing is realistic.
Cash outflow	Payments leaving the business	Shortens runway, especially when fixed or payroll-heavy.
Net burn	Monthly cash outflow minus monthly collected cash	Shows the recurring cash shortfall before one-time events.
Safety floor	Minimum balance kept as a management buffer	Creates an earlier action line than zero cash.

Runway planning is most helpful when it separates timing risk from structural risk. A timing problem may come from a large receivable slipping from one month to the next. A structural problem comes from an operating model where recurring outflows exceed recurring inflows for too long. Both can produce the same low bank balance, but the response is different: collections and payment terms help the first case, while pricing, staffing, fixed costs, funding, or business-model changes may be needed for the second.

A reserve floor matters because zero cash is usually too late for calm decisions. A business may need several weeks to collect overdue invoices, negotiate supplier terms, trim discretionary spend, secure an owner injection, or speak with lenders. Treating the floor as the management trigger gives the owner time before missed obligations become the only choices left.

The most common mistake is counting money that is visible but not truly available. Customer deposits, restricted grant money, sales tax collected for remittance, payroll withholdings, or funds reserved for a lender covenant can make the account balance look safer than it is. A useful runway forecast uses conservative cash assumptions, then revisits them after every material collection, payroll run, tax payment, or funding decision.

How to Use This Tool:

Use the calculator as a monthly cash forecast. Start with the closest profile, replace the defaults with your own cash records, then compare the base result against expense cuts, receivable stress, inflow upside, and bridge funding.

Choose a Business profile or select Custom cash plan. Profiles load starting patterns for service, agency, retail, software, and restaurant cases, but every amount remains editable.
Set the Currency symbol, then enter Current cash balance. The symbol changes display labels only, so keep every amount in the same currency.
Enter Monthly cash inflow, Receivables due soon, and Average collection delay. Use cash expected to hit the bank, not invoice revenue that may still be unpaid.
Add outflows through Monthly fixed outflow, Payroll and contractor outflow, and Monthly variable outflow. The calculator combines them into the recurring monthly cash-out base.
Set Monthly inflow growth, Monthly outflow growth, Safety cash floor, Forecast horizon, and Forecast start month. If a value triggers an input warning, correct it before relying on the tables or charts.
Open Advanced when timing matters. Payable timing delay shifts part of outflow into the following month, Planned funding or owner injection adds one-time cash in the chosen Funding month, and scenario controls test expense cuts, inflow upside, receivable delays, bridge targets, and rounding precision.
Read the summary status first, then compare Runway Snapshot, Monthly Projection, Cash Balance Path, Runway Scenario Spread, Scenario Matrix, and Action Thresholds. A result is ready when the summary no longer reports validation problems and the month-by-month projection reflects the cash events you expect.

Interpreting Results:

Cash runway is the modeled time until projected cash reaches zero. Cash positive appears only when recurring monthly cash flow is non-negative and zero cash is not reached within the selected horizon.

Safety floor breach deserves attention even when the zero-cash date is far away. A floor breach can signal that payroll comfort, supplier leverage, tax timing, lender covenants, or owner risk tolerance is already under pressure.

Net monthly cash flow compares recurring cash in with fixed, payroll, and variable outflows before one-time receivables, funding, growth, and timing adjustments.
Bridge funding need estimates the amount required to keep ending cash above the safety floor through the selected target window. It is a planning gap, not a financing offer or approval signal.
Scenario Matrix is the false-confidence check. If a receivable-stress case moves the floor date forward, collections may matter more than headline revenue. If an expense cut adds little runway, fixed-cost or funding decisions may be unavoidable.
Action Thresholds maps early floor, 3-month, 6-month, receivable, expense-lever, and bridge-funding triggers to operating moves. Use those cues to decide what must happen before the next cash close.

Technical Details:

The forecast is a month-by-month cash balance model. Each row starts with the prior ending cash, adds recurring collections, adds a receivable or funding event when its timing falls in that month, subtracts modeled cash outflow, and stores the ending balance for zero and safety-floor crossing checks.

Receivable timing and payable timing change the month in which cash appears or leaves, not the underlying amount. Growth assumptions compound monthly, so a small inflow or outflow percentage can materially change later forecast months. Expense-cut, inflow-upside, receivable-stress, and bridge scenarios reuse the same core projection with adjusted assumptions.

Formula Core:

Month t starts at zero for the first forecast month. Receivables are placed in the month determined by collection delay, while payable delay is converted to a deferral share from 0 to 1.

\begin{array}{lll} I_{t} & = & I_{base} \times {(1 + g_{i})}^{t} + R_{t} + F_{t} \\ O_{scheduled, t} & = & O_{base} \times m \times {(1 + g_{o})}^{t} \\ O_{cash, t} & = & O_{scheduled, t} \times (1 - d) + O_{scheduled, t - 1} \times d \\ C_{t + 1} & = & C_{t} + I_{t} - O_{cash, t} \\ G_{bridge} & = & max (0, C_{floor} - C_{min target}) \end{array}

Cash flow runway formula variables
Symbol	Meaning	Source in the model
`C_t`	Cash balance at the start of month `t`	Begins with Current cash balance
`I_base`	Recurring collected cash before growth	Monthly cash inflow
`O_base`	Fixed, payroll, and variable outflows combined	Monthly fixed outflow plus payroll plus variable outflow
`R_t`	One-time receivable in the modeled collection month	Receivables due soon and average collection delay
`F_t`	One-time funding in the selected month	Planned funding or owner injection and funding month
`g_i`, `g_o`	Monthly inflow and outflow growth rates after percent conversion	Growth controls, including scenario adjustments
`m`	Scenario outflow multiplier	Base, expense-cut, or stress comparison
`d`	Payable deferral share, calculated as delay days divided by 30 and capped from 0 to 1	Payable timing delay

Zero-cash and reserve-floor dates are interpolated inside the month where the projected balance crosses the threshold. If the beginning balance is above the threshold and the ending balance falls below it, the crossing fraction is the distance from the beginning balance to the threshold divided by the month's cash decline.

Cash runway risk label boundaries
Risk label	Boundary used	Planning meaning
Cash positive	Recurring net cash flow is non-negative and zero is not reached	Check floor timing anyway when starting cash is low.
Critical runway	Cash reaches zero in 3 months or less	Immediate collections, funding, or cost action is needed.
Tight runway	Cash reaches zero in more than 3 months and up to 6 months	Do not wait for a normal planning cycle to decide.
Review soon	Cash reaches zero in more than 6 months and up to 12 months	Prepare options and monitor large assumptions closely.
Floor watch	No earlier zero-cash label applies, but the safety floor is breached within 6 months	The reserve policy is at risk before the bank balance reaches zero.
Healthy runway	No zero-cash date or early floor breach appears in the forecast	Keep updating the forecast after material cash events.

With the main-street service defaults, opening cash is $85,000, recurring monthly cash in is $42,000, and recurring monthly cash out is $45,100, so recurring net burn is $3,100 before growth and one-time receivables. Because the default forecast also includes an $18,000 receivable and modest inflow growth, the 18-month projection stays above the $30,000 floor, which is why the scenario spread is more informative than the burn number alone.

Limitations, Privacy, and Accuracy Notes:

The forecast is a planning model, not accounting, tax, lending, legal, or investment advice. It does not reconcile bank feeds, verify invoices, apply exchange rates, inspect debt covenants, or model jurisdiction-specific payroll and tax timing outside the values entered.

Use one currency throughout. The currency symbol is display text, not a conversion setting.
Enter receivables only when collection timing is plausible, and test a slower collection case when a customer is material to cash flow.
Use payable delay for agreed timing or planned payment terms, not for missed payroll, tax, or critical supplier obligations.
The calculation uses the values entered in the page. Shared exports, copied JSON, or URLs with saved assumptions can reveal sensitive cash information.
Refresh the forecast after payroll, loan payments, tax remittances, owner draws, funding decisions, large invoices, or customer delays.

Worked Examples:

Conservative service-business base case

A service business starts with $85,000, expects $42,000 in monthly collected cash, has $18,000 due soon, and spends $45,100 per month before growth. The recurring burn is $3,100, but the default 18-month projection stays above the $30,000 floor because the receivable arrives early and inflow grows slightly. The right follow-up is to compare the receivable-stress and expense-cut scenarios, not to stop at the burn number.

Seasonal retail slowdown

The seasonal retail profile starts with $112,000 and a $45,000 floor, but monthly cash in is below monthly cash out and inflow declines while outflows rise. In the default June 2026 timing, the floor is breached around November 2, 2026 and cash reaches zero around December 25, 2026. An 18% expense-cut scenario pushes those dates later, which shows how much time cost action buys.

Seed-stage SaaS funding window

The seed-stage SaaS profile carries high payroll and contractor spend. With the default values, the safety floor is reached in about 2.7 months and zero cash in about 3.9 months from the June 2026 start. The bridge scenario is useful here because it turns a runway warning into a target amount and month for owner, lender, or investor planning.

Advanced Tips:

Set Safety cash floor from the minimum cash needed for payroll, tax timing, supplier leverage, and owner comfort, not from an arbitrary percentage of revenue.
Use Receivable stress delay for large customers with slow approval cycles, disputed invoices, or payment terms longer than the normal average.
Compare Expense cut scenario with Inflow upside scenario. A cost cut that adds little runway may be less useful than faster collections, and the reverse can also be true.
Use Bridge target to size capital around a reserve floor and a time window. The resulting funding need should still be reconciled against fees, repayments, covenants, and owner risk.
Keep Money precision low for management review and higher only when copying tables into a detailed cash model.

FAQ:

Why can a profitable business have short cash runway?

Profit can include revenue before cash is collected and expenses before or after cash is paid. Runway follows projected bank cash, so receivable timing, inventory, payroll, debt service, and tax dates can dominate the short-term result.

Should receivables be entered as monthly inflow?

Use Monthly cash inflow for recurring collections and Receivables due soon for one-time expected collections near the forecast start. The collection delay controls when that one-time cash appears.

Why does payable delay improve early cash?

Payable delay shifts part of scheduled outflow into the following month. It can improve the near-term balance, but it does not remove the obligation and should reflect agreed terms or a deliberate plan.

What should I do when the forecast shows no zero-cash date?

Check the safety floor, ending cash, and scenario spread. A forecast can avoid zero cash inside the selected horizon while still relying on a late receivable, optimistic growth, or a reserve balance that is too thin for the business.

Glossary:

Cash runway: How long projected cash lasts before it reaches zero or another planning threshold.
Net burn: The recurring cash shortfall when monthly cash out exceeds monthly collected cash.
Safety floor: The minimum cash balance kept available before management takes corrective action.
Bridge funding: Temporary capital needed to keep cash above the selected floor through the chosen target period.
Receivable stress: A scenario that delays expected customer collections to test whether cash tightens before money arrives.

References:

How Much Cash Should a Small Business Keep in Reserve?, SCORE, October 2, 2018.
How Net 30 Accounts Help Conserve Business Cash Flow, U.S. Small Business Administration, September 13, 2016.
Cash Runway: Formula and Calculator, Wall Street Prep.

Cash Flow Runway Calculator

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How to Use This Tool:

Interpreting Results:

Technical Details:

Formula Core:

Limitations, Privacy, and Accuracy Notes:

Worked Examples:

Conservative service-business base case

Seasonal retail slowdown

Seed-stage SaaS funding window

Advanced Tips:

FAQ:

Glossary:

References: