Calculate Startup Runway in Google Sheets
Calculate net burn, startup runway, cash depletion month, and a funding-action date with reproducible spreadsheet formulas.
Startup runway estimates how many months a business can operate before exhausting its available cash. When monthly net burn is positive, use this formula:
Runway in months = available cash ÷ monthly net burn
This guide explains how to build one worksheet in Google Sheets or Excel. It calculates current runway, models an immediate forecast scenario, estimates the cash-depletion month, and works backward from a funding lead time you choose. These outputs are planning estimates, not exact predictions.
What You'll Need
- Google Sheets or Microsoft Excel
- Current available cash reconciled to your financial records
- Representative monthly cash inflows and outflows
- Known recurring changes and one-time planned spending
- Cash values recorded in one currency; this example uses USD
- A month-end reporting date
Step-by-Step Guide
Enter current cash and burn inputs
Create a worksheet named Runway. Use column A for labels and column B for inputs, formulas, and results.
Enter these illustrative values:
| Label cell | Label | Value cell | Value | Unit |
|---|---|---|---|---|
| A2 | As-of month-end date | B2 | 2026-03-31 | Date |
| A3 | Available cash | B3 | 600000 | USD |
| A4 | Monthly cash inflows | B4 | 50000 | USD/month |
| A5 | Monthly cash outflows | B5 | 125000 | USD/month |
| A6 | Current monthly net burn | B6 | Formula in Step 2 | USD/month |
| A7 | Current runway | B7 | Formula in Step 3 | Months |
| A8 | Estimated depletion month | B8 | Formula in Step 3 | Date |
Available cash should include funds the business can use for operations. Exclude restricted funds, unsigned contracts, and expected financing that hasn’t arrived.
Base the calculation on cash movements rather than accounting profit:
- B4 can include collected customer payments and other operating receipts.
- B5 can include payroll, software, rent, marketing, taxes, and other cash payments.
- Exclude non-cash expenses such as depreciation.
Calculate monthly net burn
Monthly net burn equals monthly cash outflows minus monthly cash inflows. Enter this formula in B6:
=IF(OR(NOT(ISNUMBER(B4)),NOT(ISNUMBER(B5)),B4<0,B5<0),"Check inputs",B5-B4)
For the sample inputs:
125000 - 50000 = 75000 USD/month
The expected value in B6 is 75000.
Here’s how to interpret the result:
- Positive net burn means the startup is consuming cash.
- Zero net burn means recurring inflows equal recurring outflows.
- Negative net burn means inflows exceed outflows under the entered assumptions.
Instead of treating blank, text, or negative inputs as zero, the formula flags them for review.
Calculate runway and the depletion month
Enter this formula in B7:
=IF(OR(NOT(ISNUMBER(B3)),B3<0,NOT(ISNUMBER(B6))),"Check inputs",IF(B3=0,0,IF(B6<=0,"No finite runway at current burn",B3/B6)))
For the example:
600000 ÷ 75000 = 8 months
The expected value in B7 is 8.
Notice that the zero-cash test comes before the nonpositive-burn test. If available cash is already zero, the worksheet reports zero runway.
Next, enter this formula in B8 to estimate the month-end period in which cash would be exhausted:
=IF(NOT(ISNUMBER(B2)),"Not applicable",IF(OR(B2<DATE(1900,1,1),B2>DATE(9999,12,31),B2<>INT(B2)),"Not applicable",IF(B2<>EOMONTH(B2,0),"Not applicable",IF(NOT(ISNUMBER(B7)),"Not applicable",IFERROR(EOMONTH(B2,ROUNDUP(B7,0)),"Not applicable")))))
With an as-of date of March 31, 2026 and 8 months of runway, the expected value in B8 is November 30, 2026.
Format B7 as a number and B8 as a date. When runway includes a partial month, ROUNDUP assigns depletion to the next monthly period. Then, EOMONTH returns that period’s final day. The result is an estimated depletion month, not an exact depletion day.
If receipts, hires, or expenses begin in different months, use a month-by-month projection such as the one in Forecast Cash Runway in Excel or Google Sheets.
Add an immediate forecast scenario
Now add a scenario for forecast cash inflows, recurring outflows, and one-time spending.
| Label cell | Label | Value cell | Value | Unit |
|---|---|---|---|---|
| A11 | Forecast monthly cash inflows | B11 | 65000 | USD/month |
| A12 | Forecast monthly cash outflows | B12 | 145000 | USD/month |
| A13 | One-time planned spending | B13 | 40000 | USD |
| A14 | Cash after one-time spending | B14 | Formula below | USD |
| A15 | Forecast monthly net burn | B15 | Formula below | USD/month |
| A16 | Adjusted runway | B16 | Formula below | Months |
| A17 | Adjusted depletion month | B17 | Formula below | Date |
This simplified scenario makes 3 timing assumptions:
- B11 begins immediately and stays constant throughout the forecast.
- B12 begins immediately and stays constant throughout the forecast.
- B13 is deducted immediately from available cash.
B11 can represent a change in collected revenue. B12 can include a new hire or other recurring spending, while B13 represents a cost paid once.
These formulas aren’t suitable for a hire starting in 4 months, delayed revenue growth, or a future one-time payment. To account for those changes, place them in the specific months when they occur using a month-by-month cash forecast.
In B14, calculate cash after the immediate one-time cost:
=IF(OR(NOT(ISNUMBER(B3)),NOT(ISNUMBER(B13)),B3<0,B13<0,B13>B3),"Check inputs",B3-B13)
Expected result:
600000 - 40000 = 560000 USD
Then, calculate forecast net burn in B15:
=IF(OR(NOT(ISNUMBER(B11)),NOT(ISNUMBER(B12)),B11<0,B12<0),"Check inputs",B12-B11)
Expected result:
145000 - 65000 = 80000 USD/month
In B16, calculate adjusted runway:
=IF(OR(NOT(ISNUMBER(B14)),NOT(ISNUMBER(B15))),"Check inputs",IF(B14=0,0,IF(B15<=0,"No finite runway at forecast burn",B14/B15)))
Expected result:
560000 ÷ 80000 = 7 months
Finally, enter this formula in B17:
=IF(NOT(ISNUMBER(B2)),"Not applicable",IF(OR(B2<DATE(1900,1,1),B2>DATE(9999,12,31),B2<>INT(B2)),"Not applicable",IF(B2<>EOMONTH(B2,0),"Not applicable",IF(NOT(ISNUMBER(B16)),"Not applicable",IFERROR(EOMONTH(B2,ROUNDUP(B16,0)),"Not applicable")))))
The expected value in B17 is October 31, 2026. Under these timing assumptions, the scenario reduces estimated runway from 8 months to 7 months.
Calculate a funding-action date
A funding-action date works backward from the adjusted depletion month using a lead time selected by the founder.
Enter:
| Label cell | Label | Value cell | Value | Unit |
|---|---|---|---|---|
| A18 | Funding lead time | B18 | 3 | Whole months |
| A19 | Funding-action date | B19 | Formula below | Date |
The 3-month lead time is an illustrative assumption, not a universal recommendation. Choose a period appropriate for the financing, cost reduction, or other action being considered.
Enter this formula in B19:
=IF(OR(NOT(ISNUMBER(B17)),NOT(ISNUMBER(B18))),"Check inputs",IF(OR(B17<DATE(1900,1,1),B17>DATE(9999,12,31),B17<>INT(B17),B18<0,B18<>INT(B18)),"Check inputs",IF(B17<>EOMONTH(B17,0),"Check inputs",IFERROR(IF(EDATE(B17,-B18)<DATE(1900,1,1),"Check inputs",EDATE(B17,-B18)),"Check inputs"))))
Three months before October 31, 2026 is July 31, 2026, the expected value in B19.
Keep in mind that EDATE doesn’t preserve month-end in every case. For example, one month before February 28, 2026 is January 28, 2026. Treat B19 as an action date derived from your lead-time assumption, not necessarily as a month-end date or a guaranteed financing close date.
Validate and check the worksheet
Add data validation to reduce input errors:
- Require B2 to contain a month-end date.
- Require nonnegative numbers in B3:B5 and B11:B13.
- Require B18 to contain a nonnegative whole number.
For B2, use this custom validation formula:
=IF(NOT(ISNUMBER(B2)),FALSE,IF(OR(B2<DATE(1900,1,1),B2>DATE(9999,12,31),B2<>INT(B2)),FALSE,IFERROR(B2=EOMONTH(B2,0),FALSE)))
For B18, use:
=AND(ISNUMBER(B18),B18>=0,B18=INT(B18))
In Google Sheets, open Data → Data validation. In Excel, use Data → Data Validation. Set the rule to reject invalid entries where that option is available.
Validation may not catch every pasted or imported value, so the formulas provide a second check. Don’t use N() or a general IFERROR() wrapper to convert malformed financial inputs to zero.
The following are proposed verification cases derived from the formulas; they aren’t claims that the tests were executed.
| Check | Inputs | Expected result |
|---|---|---|
| Current calculation | B2 = 2026-03-31; B3 = 600000; B4 = 50000; B5 = 125000 | B6 = 75000; B7 = 8; B8 = 2026-11-30 |
| Forecast calculation | B11 = 65000; B12 = 145000; B13 = 40000; B18 = 3 | B14 = 560000; B15 = 80000; B16 = 7; B17 = 2026-10-31; B19 = 2026-07-31 |
| Zero cash | B3 = 0; B4 = 50000; B5 = 125000 | B6 = 75000; B7 = 0; B8 equals B2 |
| Zero net burn | B3 = 600000; B4 = 125000; B5 = 125000 | B6 = 0; B7 = “No finite runway at current burn”; B8 = “Not applicable” |
| Negative net burn | B3 = 600000; B4 = 140000; B5 = 125000 | B6 = -15000; B7 = “No finite runway at current burn”; B8 = “Not applicable” |
| Blank inflow | Clear B4 | B6 = “Check inputs”; B7 = “Check inputs” |
| Malformed imported value | Paste abc into B5 in an unvalidated copy | B6 = “Check inputs”; the text isn’t converted to zero |
| Invalid one-time cost | Set B13 to -1 or greater than B3 | B14 = “Check inputs” |
| Invalid lead time | Set B18 to -1, 2.5, blank, or text | B19 = “Check inputs” |
| Zero lead time | Set B18 to 0 | B19 equals B17 |
| Month-end boundary | B2 = 2026-01-31; B3 = 75000; B4 = 50000; B5 = 125000 | B6 = 75000; B7 = 1; B8 = 2026-02-28 |
The formulas use commas as argument separators. If your spreadsheet locale requires semicolons, replace the commas with semicolons.
Update runway with current financial data
At each monthly review:
- Replace B2 with the applicable month-end date.
- Reconcile B3 to currently available cash.
- Replace B4 and B5 with representative recent monthly cash movements.
- Review the immediate, constant scenario assumptions in B11 and B12.
- Update B13 with immediate one-time spending that hasn’t already left the bank account.
- Reconsider the lead time in B18.
- Inspect B7, B8, B16, B17, and B19.
If a change starts later or varies by month, don’t force it into this constant-burn scenario. Instead, use a monthly projection that places each receipt or payment in its expected period.
ModelMonkey can inspect spreadsheet context and help with formulas or proposed changes in Google Sheets and Microsoft Excel. When the workflow presents a preview, review the proposed edits before proceeding. Because spreadsheet assistance doesn’t guarantee correct results, check every formula and assumption against your financial records.
A relevant prompt for this worksheet is:
Inspect the Runway sheet. Check the formulas in B6:B8 and B14:B19 against their labels, flag formula errors, and propose corrections without replacing my input values.
Wrapping Up
The completed worksheet calculates current runway, an immediate scenario-adjusted runway, an estimated cash-depletion month, and a funding-action date based on your chosen lead time.
With the illustrative inputs, current runway is 8 months and adjusted runway is 7 months. Keep the calculation current with reconciled cash and updated operating assumptions. When the timing of revenue, hiring, or planned spending varies, switch to a month-by-month forecast.
Frequently Asked Questions
What is startup runway?
Startup runway is the estimated time a business can continue operating before exhausting its available cash under defined cash-inflow and cash-outflow assumptions.
Should runway use gross burn or net burn?
Use net burn to estimate how quickly available cash is declining:
Monthly net burn = monthly cash outflows - monthly cash inflows
Gross burn measures total outflows without subtracting cash inflows.
What happens if net burn is zero or negative?
If cash remains, there’s no finite depletion period under the entered assumptions. Zero net burn means inflows equal outflows, while negative net burn means inflows exceed outflows.
If available cash is already zero, runway is zero regardless of the burn rate.
How should one-time costs affect runway?
Subtract a one-time cost from available cash once. Don’t include it in monthly burn unless it recurs. This worksheet assumes the cost is deducted immediately; a future payment belongs in the month when it is expected to occur.
Can this method model a hire that starts later?
Not accurately with the Step 4 formulas. They assume forecast inflows and outflows begin immediately and remain constant. Use a month-by-month forecast for staged hiring, delayed revenue changes, annual payments, or other time-dependent cash movements.
Is the estimated depletion date exact?
No. It identifies an estimated monthly period based on the entered assumptions. Uneven collections, taxes, hiring dates, financing, and other cash movements can change the actual date.
How often should a founder recalculate runway?
Recalculate runway whenever material cash assumptions change and as part of a consistent monthly financial review. Use reconciled cash and current operating data rather than carrying stale values forward.