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Free startup finance tool

Startup runway calculator.

Estimate monthly cash burn, runway and the point at which projected cash may fall below your chosen safety buffer—using cash in and cash out, not accounting profit.

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The cash distinction

A bank balance is not a cash-flow forecast.

Runway is the period a business can continue operating before available cash reaches a critical level, based on the assumptions entered. The useful question is not only what cash exists today, but what is expected to arrive and leave next.

The model brings together:

  • Expected cash receipts rather than invoices raised or accounting revenue
  • Payroll, suppliers, rent, software, finance, tax and other cash payments
  • A minimum operating cash buffer chosen by the founder
  • Growth assumptions and specific one-off cash movements
01
Simple mode

Enter the current cash run-rate.

Use cash you expect to receive and pay—not accounting revenue, EBITDA or profit.

Core cash inputs
Advanced assumptionsGrowth and one-off movements
02

24-month projection

Your cash runway view.

Estimated runway to £010 months

Based on the month-by-month cash assumptions entered above.

Current monthly net burn£10,000At the current run-rate
Runway to buffer10 monthsAt or below £0
Cash after 3 months£70,000Projected closing cash
Cash after 6 months£40,000Projected closing cash
Cash after 12 months-£20,000Projected closing cash
Cash pressure pointMonth 11First month below the buffer
Projected cash positionMonth 24: -£140,000
Projected closing cash over 24 monthsThe line plots projected monthly closing cash. It includes a zero-cash line and the selected minimum cash buffer.£0NowM6M12M18M24
Month-by-month cash breakdownOpening cash, movements and closing cash

  1. Month 1

    Opening cash
    £100,000
    Cash inflows
    £10,000
    Cash outflows
    −£20,000
    One-off movements
    None
    Closing cash
    £90,000

  2. Month 2

    Opening cash
    £90,000
    Cash inflows
    £10,000
    Cash outflows
    −£20,000
    One-off movements
    None
    Closing cash
    £80,000

  3. Month 3

    Opening cash
    £80,000
    Cash inflows
    £10,000
    Cash outflows
    −£20,000
    One-off movements
    None
    Closing cash
    £70,000

  4. Month 4

    Opening cash
    £70,000
    Cash inflows
    £10,000
    Cash outflows
    −£20,000
    One-off movements
    None
    Closing cash
    £60,000

  5. Month 5

    Opening cash
    £60,000
    Cash inflows
    £10,000
    Cash outflows
    −£20,000
    One-off movements
    None
    Closing cash
    £50,000

  6. Month 6

    Opening cash
    £50,000
    Cash inflows
    £10,000
    Cash outflows
    −£20,000
    One-off movements
    None
    Closing cash
    £40,000

  7. Month 7

    Opening cash
    £40,000
    Cash inflows
    £10,000
    Cash outflows
    −£20,000
    One-off movements
    None
    Closing cash
    £30,000

  8. Month 8

    Opening cash
    £30,000
    Cash inflows
    £10,000
    Cash outflows
    −£20,000
    One-off movements
    None
    Closing cash
    £20,000

  9. Month 9

    Opening cash
    £20,000
    Cash inflows
    £10,000
    Cash outflows
    −£20,000
    One-off movements
    None
    Closing cash
    £10,000

  10. Month 10

    Opening cash
    £10,000
    Cash inflows
    £10,000
    Cash outflows
    −£20,000
    One-off movements
    None
    Closing cash
    £0

  11. Month 11

    Opening cash
    £0
    Cash inflows
    £10,000
    Cash outflows
    −£20,000
    One-off movements
    None
    Closing cash
    -£10,000

  12. Month 12

    Opening cash
    -£10,000
    Cash inflows
    £10,000
    Cash outflows
    −£20,000
    One-off movements
    None
    Closing cash
    -£20,000

  13. Month 13

    Opening cash
    -£20,000
    Cash inflows
    £10,000
    Cash outflows
    −£20,000
    One-off movements
    None
    Closing cash
    -£30,000

  14. Month 14

    Opening cash
    -£30,000
    Cash inflows
    £10,000
    Cash outflows
    −£20,000
    One-off movements
    None
    Closing cash
    -£40,000

  15. Month 15

    Opening cash
    -£40,000
    Cash inflows
    £10,000
    Cash outflows
    −£20,000
    One-off movements
    None
    Closing cash
    -£50,000

  16. Month 16

    Opening cash
    -£50,000
    Cash inflows
    £10,000
    Cash outflows
    −£20,000
    One-off movements
    None
    Closing cash
    -£60,000

  17. Month 17

    Opening cash
    -£60,000
    Cash inflows
    £10,000
    Cash outflows
    −£20,000
    One-off movements
    None
    Closing cash
    -£70,000

  18. Month 18

    Opening cash
    -£70,000
    Cash inflows
    £10,000
    Cash outflows
    −£20,000
    One-off movements
    None
    Closing cash
    -£80,000

  19. Month 19

    Opening cash
    -£80,000
    Cash inflows
    £10,000
    Cash outflows
    −£20,000
    One-off movements
    None
    Closing cash
    -£90,000

  20. Month 20

    Opening cash
    -£90,000
    Cash inflows
    £10,000
    Cash outflows
    −£20,000
    One-off movements
    None
    Closing cash
    -£100,000

  21. Month 21

    Opening cash
    -£100,000
    Cash inflows
    £10,000
    Cash outflows
    −£20,000
    One-off movements
    None
    Closing cash
    -£110,000

  22. Month 22

    Opening cash
    -£110,000
    Cash inflows
    £10,000
    Cash outflows
    −£20,000
    One-off movements
    None
    Closing cash
    -£120,000

  23. Month 23

    Opening cash
    -£120,000
    Cash inflows
    £10,000
    Cash outflows
    −£20,000
    One-off movements
    None
    Closing cash
    -£130,000

  24. Month 24

    Opening cash
    -£130,000
    Cash inflows
    £10,000
    Cash outflows
    −£20,000
    One-off movements
    None
    Closing cash
    -£140,000

Simplified cash planning tool. This calculator projects recurring monthly cash inflows and outflows using the assumptions entered. It is not a detailed cash-flow forecast, accounting projection, tax calculation, funding recommendation or investment advice.

Calculations run locally in your browser. The values you enter are not saved, submitted to SCALEHOUSE or attached to analytics events.

Burn rate vs runway

How quickly cash is used—and how long it may last.

Burn rate is how quickly cash is being consumed. This calculator uses current monthly cash outflows less current monthly cash inflows and never presents a cash surplus as a negative burn.

Runway is how long current and projected cash lasts. Here it is modelled month by month, including growth assumptions, a chosen cash buffer and any one-off movements entered.

Upcoming payroll, VAT or other taxes, supplier payments, debtor timing, finance movements and exceptional costs can materially change the picture. A detailed forecast should use the business's actual timing and evidence.

Read the startup cash-flow forecasting guide

Use the result

Turn one runway answer into a better set of questions.

The base case is only one possible path. Change the assumptions deliberately to understand which decisions have the greatest effect on cash headroom.

  1. 01

    Test slower receipts

    Reduce expected cash inflow or apply negative growth to see how quickly runway changes.

  2. 02

    Test a new hire

    Increase monthly outflows or add a one-off recruitment cost in the expected month.

  3. 03

    Model a large payment

    Add equipment, a deposit, tax or another exceptional cash cost in the month it may leave the bank.

  4. 04

    Include committed cash

    Add a deliberately modelled funding or director cash receipt without treating it as guaranteed investment.

  5. 05

    Choose a safety buffer

    Set the cash level the business should not fall below and identify the first pressure point.

When the simple model is not enough

Build the forecast around the real business.

A detailed model can replace broad monthly assumptions with actual debtor timing, payroll, taxes, supplier commitments, finance movements and commercial scenarios.

From £495

13-week cash-flow forecasting

A detailed weekly view of expected receipts, payments, headroom and near-term cash pressure.

From £995

Integrated Forecast

A connected profit, balance-sheet and cash model built around the commercial plan and its assumptions.

From £195/month

Rolling Forecast Updates

A repeatable update rhythm once a suitable forecast model already exists.

Prices are starting points. Final fees depend on scope, volume and complexity.

Cash visibility

Need a forecast built around the real business?

Move from broad runway assumptions to a forecast built around customer receipts, payroll, suppliers, taxes, financing and the decisions ahead.

Explore Cash-Flow ForecastingBook a quick chat