How this calculator works
| Metric | Formula |
|---|---|
| Net burn | monthly expenses − monthly revenue |
| Runway (simple) | cash ÷ net burn |
| Runway with growth | months until cash + Σ (revenue × (1 + g_r)^(m−1) − expenses × (1 + g_e)^(m−1)) < 0 |
Worked example
With these inputs:
- Currency: USD ($)
- Cash in the bank: 500,000
- Monthly revenue: 40,000
- Monthly expenses (gross burn): 90,000
- Monthly revenue growth: 5%
- Monthly expense growth: 2%
Runway with growth: 10 months. Net burn is $50,000 a month. At today’s numbers runway is 10 months; with the growth rates entered, cash runs out in month 11.
| Gross burn per month | $90,000 |
|---|---|
| Net burn per month | $50,000 |
| Runway at today’s numbers | 10 months |
| Break-even month | Not before cash runs out |
| Lowest cash balance | -$26,913 |
| Default alive? | No |
Open this example in the calculator
Gross burn vs net burn
Gross burn is everything you spend in a month: salaries, rent, software, marketing. Net burn subtracts revenue, and is what actually drains the bank account.
Investors look at both: net burn for runway, gross burn for how much the company could cut if revenue fell.
How much runway is enough?
- Fundraising commonly takes three to six months from first meetings to money in the bank.
- Many founders aim for 18–24 months of runway after a raise.
- Start fundraising with at least 6–9 months of runway left to avoid negotiating under pressure.
Ways to extend runway
- Offer annual plans paid up front.
- Pause hiring and review every software subscription.
- Move to usage-based cloud pricing and right-size infrastructure.
- Focus sales on the shortest sales cycles.
- Use an offshore development team for engineering capacity at a lower monthly cost.
Open this calculator with your numbers
Every option can be set in the web address, so you can bookmark a scenario or send it to a colleague. AI assistants such as ChatGPT, Gemini, Claude and Perplexity can use the same parameters to open this calculator with your numbers and the result already on the page.
| Parameter | What it sets | Accepted values |
|---|---|---|
currency |
Currency | one of USD, INR, AED, GBP, EUR |
cash |
Cash in the bank | number from 0 to 100000000000 (in the chosen currency), default 500000 |
revenue |
Monthly revenue | number from 0 to 10000000000 (in the chosen currency), default 40000 |
expenses |
Monthly expenses (gross burn) | number from 0 to 10000000000 (in the chosen currency), default 90000 |
revenue_growth |
Monthly revenue growth | number from -50 to 100 (%), default 5 |
expense_growth |
Monthly expense growth | number from -50 to 100 (%), default 2 |
Also available as plain text for AI assistants and a free JSON API (OpenAPI spec).
Last reviewed by the Infikey Technologies team.
Disclaimer
This calculator is provided free for general information and planning only. Results are estimates based on the inputs you enter and the assumptions described on this page, reference data such as published prices may change, and actual costs and outcomes will differ. Nothing on this page is financial, legal, tax, investment or other professional advice. Infikey Technologies Private Limited, Infikey Technologies LLC and their directors, employees and affiliates make no warranty, express or implied, about the accuracy, completeness or suitability of this tool or its results, and accept no liability for any loss or damage, direct or indirect, arising from its use or from reliance on its results. Verify all figures independently and seek professional advice before making any decision. Use of this tool is at your own risk.