Cash Flow & Runway Planner

How it works

Build a forecast from cash timing rather than accounting profit

Enter the cash available at the start of the forecast and the sales receipts you expect in the first month. Receipts are money actually collected, which may differ from invoices issued or revenue recognized in accounting. Fixed cash expenses are the recurring payments in that same month. Variable cash costs are modeled as a percentage of sales receipts, so they rise or fall with the sales scenario.

Growth rates are monthly. A 2% monthly increase compounds from one month to the next; it is not the same as a 2% annual increase. Use negative rates for declining receipts or expenses, within the permitted range. Add financing receipts, equipment purchases, or other exceptional movements as one-time rows with a month number and direction. Those rows do not automatically recur in later months.

Cash-runway example with a recurring monthly shortfall

Suppose opening cash is 30,000, monthly sales receipts are 8,000, fixed expenses are 10,000, and variable costs are 20% of sales. Variable expenses are 1,600, so the recurring monthly net burn is 3,600. With no growth or one-time movements, simple runway is 30,000 ÷ 3,600, or approximately 8.33 months.

The month-end forecast shows 1,200 remaining after month eight and a balance of −2,400 after month nine. A 5,000 safety buffer is breached in month seven, when cash ends at 4,800. These are different signals: the buffer gives an earlier planning threshold, while the nonpositive balance identifies the first month-end at or below zero. The forecast does not establish the exact day cash would run out.

Use the schedule to locate funding gaps

The monthly table separates sales receipts, other cash in, fixed expenses, variable expenses, and other cash out. This makes an unusual purchase or financing event visible instead of burying it inside a growth rate. The lowest projected balance includes the opening balance at month zero. Funding needed to maintain the buffer is the difference between the desired buffer and that lowest balance, when positive.

The forecast continues below zero to show the size of a potential gap. A negative balance is not an assumed overdraft approval or an automatic funding source. You can add a proposed cash injection as a new scenario and compare how it changes the timing. Likewise, delaying an expense changes cash timing even when it does not alter the total amount paid across the forecast.

Keep the constant-burn shortcut separate from the full model

The simple runway metric uses the first month’s recurring net burn and excludes one-time movements and future growth. If that month does not burn cash, the shortcut reports no recurring first-month cash burn instead of an infinite number of months. The forecast can still show later trouble if costs grow, receipts fall, or a large one-time outflow occurs.

This model does not calculate receivables, payables, inventory financing, taxes, or payroll rules automatically. Include their expected cash effects in your inputs where relevant. Forecast months must be whole numbers, and one-time movements must fall inside the chosen horizon. Save a base case and alternatives with clear names, then update actual balances and assumptions as new information becomes available.

Monthly cash flow & runway: formula and assumptions

Ending cash = opening cash + sales receipts + other inflows − fixed expenses − variable expenses − other outflows. Constant-burn runway = starting cash ÷ first-month recurring net burn.

Growth compounds monthly from the first month. Each one-time movement is applied in its selected month. Monthly rows are cash forecasts, not accrual profit statements. Negative balances represent a funding gap; the model does not assume a lender supplies the difference.

Worked example

Reference example currency: USD. These fixed examples do not change with your calculator preferences.

Using the Monthly cash flow & runway example:

Opening cash balance ($)

30000

First-month cash receipts from sales ($)

8000

Monthly sales-receipt growth (%)

0

First-month fixed cash expenses ($)

10000

Monthly fixed-expense growth (%)

0

Variable cash costs as a share of sales (%)

20

Minimum cash safety buffer ($)

5000

Forecast length (months)

12

One-time cash movements

None

Ending cash = opening cash + sales receipts + other inflows − fixed expenses − variable expenses − other outflows. Constant-burn runway = starting cash ÷ first-month recurring net burn.

Example result

• Month zero is your starting balance. Cash reaches zero or below when the period-ending balance is nonpositive; intramonth timing is not modeled.
• Constant-burn runway excludes growth and one-time movements. The full monthly forecast includes them.

These are illustrative inputs. Change the values to explore a different scenario.

What to keep in mind

Use one currency throughout. Currency selection changes labels, not exchange rates. Calculate, then save a named scenario in My workspace to keep it in this browser; export a workspace backup to move it to another device.

Formula references

• SBA: manage your business finances (opens in a new tab)

References explain the underlying methods; they do not imply endorsement or individual professional review of Finflo.

Common questions