Skip to content

Cash runway calculator

How many months does your cash last, what revenue stops the burn, and does your growth get there first? The costs that grow with sales grow with them.

What you can spend now. Leave out stock and money owed to you.

Cash in from sales, after refunds, without VAT.

Product, shipping and payment fees, plus ad spend if it rises with sales, as a % of revenue.

Salaries, rent, software, a flat ad budget, loan repayments.

Your own forecast; a minus sign for a decline. Empty keeps revenue flat.

Result

Fill in cash in the bank, revenue per month, costs that grow with sales, fixed costs per month to see the result.

How it works

Runway is how long your cash lasts at the rate you are using it: cash divided by net burn, the cash going out each month minus the cash coming in.

For a store, part of the costs grow with every sale (the product, shipping, payment fees) and part stay fixed (salaries, rent, software). So more revenue closes the gap only by what is left of each extra sale after its own costs, not by the whole sale. With a growth rate, the calculator walks the balance month by month to see whether revenue covers costs before the cash runs out.

net burn = fixed costs
  - revenue × (1 - share of costs
    that grow with sales)
runway = cash ÷ net burn

revenue that covers costs =
  fixed costs ÷ (1 - that share)

with growth, month by month:
  revenue × (1 + growth)
  cash = cash + revenue
    × (1 - that share) - fixed costs

What each term means

Cash in the bank
What you can spend now. Leave out stock, and money owed to you that has not arrived.
Revenue per month
Cash in from sales in a normal month, after refunds and without VAT.
Costs that grow with sales
Product, shipping, payment fees, and ad spend if you scale it with sales, as a share of revenue.
Fixed costs
What goes out each month whatever you sell: salaries, rent, software, a set ad budget, loan repayments.
Net burn
Fixed costs minus what revenue leaves after the costs that grow with it.
Monthly revenue growth
Your own forecast of revenue growth per month; a minus sign for a decline.

How the growth path is counted: month one is the coming month at today's revenue, and revenue grows by your rate each month after. The last month before the cash runs out counts in part, so with no growth the path gives exactly cash ÷ net burn. The walk stops at 50 years. To see what one order leaves after its costs, use the contribution margin calculator.

Source: Corporate Finance Institute, Cash Runway Explained (runway = cash balance ÷ monthly net burn) (read 26 September 2026).

Worked example

Example numbers, round on purpose, not a real store:

Cash in the bank
€150,000
Revenue per month
€60,000
Costs that grow with sales
55%
Fixed costs per month
€40,000
Monthly revenue growth
3%
  1. 1Left from revenue: €60,000 × (1 - 55%) = €27,000
  2. 2Net burn: €40,000 - €27,000 = €13,000 a month
  3. 3Runway with no growth: €150,000 ÷ €13,000 = 11.5 months
  4. 4Revenue that covers costs: €40,000 ÷ 45% = €88,889 a month
  5. 5At 3% growth: €60,000 × 1.03¹⁴ = €90,755, so revenue covers costs in 14 months
  6. 6Lowest cash on the way: €150,000 - €98,669 burned over those 14 months = €51,331

So this example runs out of cash in under a year if nothing changes, and lasts if 3% growth a month holds, with about €51,000 left at the lowest point.

Frequently asked questions

  • What is cash runway?
    How long your cash lasts at the rate you are using it: cash in the bank divided by net burn, the cash going out each month minus the cash coming in. If more comes in than goes out, there is no burn and the cash does not run down.
  • What is the difference between gross burn and net burn?
    Gross burn is all the cash going out each month. Net burn subtracts the cash coming in. Runway uses net burn; a runway on gross burn only tells you how long the cash would last if sales stopped altogether.
  • Why split costs into ones that grow with sales and fixed ones?
    Because growth is not free. If revenue rises by €10,000 and 55% of it goes on product, shipping and fees, only €4,500 of it pays down the burn. Treating every cost as fixed makes growth look as if it closes the gap more than twice as fast as it does.
  • Should ad spend count as a cost that grows with sales?
    If you scale it with sales, for example by holding a cost per order, yes. If you set a monthly budget, it is a fixed cost. Put it in one place, the way you actually run it.
  • What does this calculator leave out?
    Timing. Stock bought ahead of a season, payout delays from payment providers, supplier terms, VAT and tax payments all move cash in months when revenue does not. For a month with a big stock purchase, add it to that month's fixed costs, or run the calculator with the cash you will have after it.

Related tools

All free tools

Next: which channels bring your orders?

Growth is the input that decides this result. Which channels actually drive it is the next question. Your GA4 export already holds how long your buyers take and which channels they touch. First finding free, in your browser; the full read is €99.

Get your first finding freeMore free tools