| Month | MRR | Expenses | Net burn | Cash |
|---|---|---|---|---|
| 1 | $25K | $60K | −$35K | $465K |
| 2 | $27K | $60K | −$33K | $432K |
| 3 | $29K | $60K | −$31K | $401K |
| 4 | $31K | $60K | −$29K | $373K |
| 5 | $34K | $60K | −$26K | $347K |
| 6 | $37K | $60K | −$23K | $323K |
| 7 | $40K | $60K | −$20K | $303K |
| 8 | $43K | $60K | −$17K | $286K |
| 9 | $46K | $60K | −$14K | $272K |
| 10 | $50K | $60K | −$10K | $262K |
| 11 | $54K | $60K | −$6K | $256K |
| 12 | $58K | $60K | −$2K | $254K |
| 13 | $63K | $60K | +$3K | $257K |
| 14 | $68K | $60K | +$8K | $265K |
| 15 | $73K | $60K | +$13K | $279K |
| 16 | $79K | $60K | +$19K | $298K |
| 17 | $86K | $60K | +$26K | $324K |
| 18 | $93K | $60K | +$33K | $356K |
| 19 | $100K | $60K | +$40K | $396K |
| 20 | $108K | $60K | +$48K | $444K |
| 21 | $117K | $60K | +$57K | $501K |
| 22 | $126K | $60K | +$66K | $566K |
| 23 | $136K | $60K | +$76K | $642K |
| 24 | $147K | $60K | +$87K | $729K |
Runway is the number of months your startup can keep operating before it runs out of cash, assuming nothing changes. It's calculated by dividing your cash balance by your net burn rate — the difference between what you spend each month and what you earn.
This calculator goes one step further than the simple division: it projects MRR growth forward, lets you stress-test growth rates, and shows the exact month you'd hit cash-flow break-even.
Runway is the single most important number in early-stage company building. It controls how much risk you can take, how aggressively you can hire, and when you have to start fundraising again.
Most experienced investors expect founders to have at least 18 months of runway after a round closes. Less than 12 months and you'll be raising under pressure — which usually means worse terms or unfavorable signaling. The most common founder mistake is to track "burn" rather than "runway given expected growth," which makes the picture look healthier than it is.
Use this calculator before every hiring decision, every investor update, and every quarterly plan review.
Use the cash you actually have today, plus credit lines you'd realistically draw on. Don't include receivables or unsigned commitments.
Monthly recurring revenue, in dollars. Use 0 if you're pre-revenue. For one-time revenue businesses, divide annual revenue by 12 as a rough proxy.
Be honest. 5–10% MoM growth is good for early-stage SaaS; anything above 15% sustained for many months is exceptional. Set growth to 0 to see the worst case.
All cash outflows: salaries (with payroll tax), infrastructure, tools, contractors, rent, legal. Be conservative — under-counting costs is the most common mistake.
Compare against your fundraising plan. If you're under 12 months at zero growth, you're already in fundraise mode whether you know it or not.