Cash balance timeline

Cash Runway Example: Estimating When Cash Runs Out

A product company has just raised funding and needs an ordinary-language estimate of when cash runs out. This example converts current cash, average inflow, and average outflow into net burn, a projected date, and checkpoint balances, then handles non-burning states without Infinity.

Practical example15 min read

Turn a funding balance into a planning horizon

FieldNote Products holds $540,000 on August 15, 2026 after a financing round. Its current operating plan averages $110,000 of monthly cash outflow and $65,000 of monthly inflow. Gross burn is the full $110,000 cost flow; net burn is the $45,000 difference that actually reduces cash.

Dividing $540,000 by $45,000 produces 12 months. Adding that horizon to the as-of date gives August 15, 2027. This date is an estimate under constant averages, not a scheduled shutdown date or guarantee that every monthly balance will follow a straight line.

The calculator provides a finite runway only when net burn is positive. If inflows equal or exceed outflows, cash is not being depleted by the entered averages. The truthful user-facing result is a cash-neutral or net-cash-generating state, not Infinity.

What we’re calculating

Balance depletion timeline

Net burn = Monthly outflow − monthly inflow; Runway = Current cash ÷ positive net burn

Current cash: $540,000 at the stated date.
Monthly outflow: $110,000 gross burn.
Monthly inflow: $65,000 replenishing cash.
Net burn: $45,000 monthly cash decline.

Estimated end date uses date-only month arithmetic. Nonpositive net burn returns no finite depletion date.

Intermediate calculations, step by step

Confirm the starting balance
Use $540,000 available on August 15, 2026, after known restricted amounts are treated consistently.
Separate gross and net burn
$110,000 gross outflow − $65,000 inflow = $45,000 positive net burn.
Calculate runway
$540,000 ÷ $45,000 = 12 months.
Project the end date
August 15, 2026 + 12 months = August 15, 2027.
Build checkpoints
Cash is $405,000 after 3 months, $270,000 after 6, $135,000 after 9, and $0 after 12.

Worked example

A twelve-month post-funding runway

The timeline holds monthly inflow and outflow constant to create a transparent baseline that management can replace with more detailed forecasts.

Current cash: $540,000
Monthly inflow: $65,000
Monthly outflow: $110,000
As-of date: August 15, 2026

Gross burn = $110,000; net burn = $110,000 − $65,000 = $45,000.
Runway = $540,000 ÷ $45,000 = 12 months.
Month 3: $540,000 − 3 × $45,000 = $405,000; month 6: $270,000.
Month 9: $135,000; month 12: $0; projected end date = August 15, 2027.

Result12 months of estimated runway, ending around August 15, 2027

Every month of delay in changing the plan consumes another modeled $45,000. The checkpoints make that consequence visible and provide review dates before the balance reaches zero.

What the owner should notice on the timeline

The gross cost base is more than twice the net depletion rate because inflows replace $65,000 each month. If collections weaken while outflows remain fixed, runway can contract quickly. If recurring inflows strengthen, the end date moves outward.

A straight-line runway should trigger decisions well before month twelve. Hiring commitments, inventory purchases, fundraising time, and minimum operating reserves may require action at the month-three or month-six checkpoint. Zero is the mathematical boundary, not a sensible planning threshold.

Four cash states in plain language

Positive net burn: with $110,000 out and $65,000 in, cash declines $45,000 monthly and runway is 12 months. Cash-neutral: at $110,000 out and $110,000 in, net burn is zero, so the entered averages do not deplete cash and there is no finite run-out date.

Net cash generation: at $110,000 out and $125,000 in, net burn is −$15,000 and cash grows by $15,000 monthly, so again there is no depletion date. Zero starting cash with positive $45,000 burn produces zero months and the as-of date as the boundary. Zero starting cash with neutral or generating movement has no finite depletion horizon to calculate; describe the state directly.

Positive burn → finite months and date.
Neutral → balance holds under the averages.
Generation → balance grows under the averages.
Zero cash + positive burn → zero runway; do not hide the immediate constraint.

Alternative: reduce outflow by $15,000

If FieldNote lowers monthly outflow to $95,000 while maintaining $65,000 inflow, net burn becomes $30,000. Runway extends to $540,000 ÷ $30,000 = 18 months.

The six-month extension is mathematically clear, but the operating effect must still be evaluated. Cutting work that protects revenue could reduce inflow later. A runway scenario should pair the cash result with the operational assumptions that make it possible.

Convert checkpoints into decision dates

The month-three balance of $405,000 is a review point, not merely a chart label. By then the team can compare actual cumulative cash change with the modeled $135,000 decline, update sales collections, and decide whether hiring or inventory commitments still fit. A difference should be explained from underlying inflow and outflow rather than patched with a new unexplained average.

Fundraising and cost changes take time. If management needs six months to close financing or unwind commitments, waiting until six months of cash remain may already be too late. The simple end date becomes more useful when paired with internal thresholds for beginning a process, slowing discretionary commitments, and protecting a minimum operating reserve.

Finite runway versus non-depletion states

Extends the planning horizon

Recurring inflows increase without equally large outflows.
Durable cost reductions lower gross burn.
The starting balance excludes restricted or already committed cash consistently.
Management refreshes assumptions at each checkpoint.

Shortens or misstates runway

One-time inflow is treated as recurring.
Inventory, taxes, or committed hires are omitted.
A net-generating state is displayed as Infinity.
The team waits for zero cash before acting.

Common mistakes

Where the calculation goes wrong

Using gross burn in the denominator

Runway uses positive net burn after average inflows, while still displaying gross burn separately.

Showing Infinity

Neutral and generating scenarios have no finite depletion date under the inputs; say that plainly.

Treating the date as certain

It is a projection from constant averages, not a calendar promise.

Ignoring zero cash

With positive burn and no starting cash, runway is zero months and the constraint is immediate.

Action checklist

Before you use the result

Confirm usable cash and the as-of date.
Use representative monthly inflow and outflow.
Calculate gross and net burn separately.
Create cash checkpoints before the projected end.
Describe neutral and generating states without Infinity.
Reforecast after material hiring, revenue, financing, or cost changes.

FAQ

Questions beyond the basic calculation

Should restricted cash be included in the balance?

Only if it is genuinely available for the modeled operating costs. Excluding unavailable funds prevents runway from overstating decision flexibility.

What if monthly cash flow is seasonal?

A single average can hide seasonal lows. Use a month-by-month forecast for operational planning and treat the calculator result as a baseline summary.

Why does cash-neutral produce no end date?

When inflow equals outflow, the entered averages do not reduce the balance. There is no finite run-out point to divide toward; ordinary language is more accurate than Infinity.

Does the projected date include a safety reserve?

No. The calculation runs to zero. Management should choose its own minimum cash threshold and act earlier based on commitments and risk.

Note: This simple runway example is educational, not a liquidity guarantee. Actual cash timing, restricted funds, financing, seasonality, taxes, and operating changes require a detailed forecast.