The clock is ticking-do you know how much time you have?
Every founder knows the sinking feeling. You're building, you're growing, but the cash in the bank is shrinking every month. One day you realize you don't know whether you have six months or twelve to reach profitability, find customers, or close a fundraise. This isn't knowledge you can afford to guess on. This calculator tells you exactly how many months of runway you have left.
What This Calculator Does
This tool takes two numbers-your current cash balance and your monthly burn rate-and tells you precisely how many months you can operate before running dry. It's the startup version of knowing how much gas you have and how fast you're using it. Feed in your cash on hand and your average monthly spend (expenses minus revenue), and the calculator shows your runway in months, weeks, and days.
How to Use This Calculator
Step 1: Find your current cash balance. Log into your bank account and add up all liquid cash: checking accounts, savings, credit lines you could draw on today. Don't include stock, equipment, or future fundraising. You only have cash you can spend right now.
Step 2: Calculate your monthly burn rate. This is your total monthly expenses minus any revenue you're bringing in. If you spend $100K/month on salaries, rent, tools, and hosting, and you bring in $30K/month in revenue, your burn rate is $70K. Some startups have zero revenue (pure burn), which is fine-just use total monthly expenses.
Step 3: Enter both numbers into the calculator. Cash on hand first, then monthly burn rate.
Step 4: Read the output. Runway is the number of months you can operate before cash hits zero. If you have $210K and burn $70K/month, you have three months. That's your deadline. Mark it on the calendar. Make decisions knowing you have to reach profitability, cut burn, or raise capital by then.
Step 5: Stress-test the number. What if burn increases 20% because you hire someone? What if revenue drops? Run the calculator with different burn rates to see the impact. A $10K increase in monthly burn cuts one month of runway. This is a powerful incentive to control spending.
The Formula Behind the Math
Runway (months)
Runway = Current Cash Balance / Monthly Burn Rate
Example:
Runway = $210,000 / $70,000 = 3 months
Understanding burn rate:
Monthly Burn = Total Monthly Expenses - Monthly Revenue
Example:
Monthly Burn = $100,000 (expenses) - $30,000 (revenue) = $70,000
If you want to know your runway in weeks:
Runway (weeks) = (Current Cash / Monthly Burn Rate) × 4.33
Example:
3 months × 4.33 = 12.99 weeks ≈ 13 weeks
If you want to know your runway in days:
Runway (days) = (Current Cash / Monthly Burn Rate) × 30
Example:
3 months × 30 = 90 days
Our calculator does all of this instantly-but now you understand exactly what it's computing.
Early-Stage Founders Just Out of Pre-Seed
You closed a $250K pre-seed round. It feels like a lot of money. You've got yourself, one engineer, and a designer. Monthly burn is $40K (salaries, office, tools). Your runway is 6.25 months. That's your timeline: reach a meaningful metric (100 users, $10K ARR, proof of traction) in six months or you'll struggle to raise Series A. This calculator makes that deadline concrete and forces prioritization.
Bootstrapped Founders Watching Savings Drain
You started with $150K in personal savings. Your saas product is growing but not yet profitable. Monthly burn is $8K. You have about 19 months of runway-but every $1K increase in monthly burn costs you a month. This calculator shows you exactly how much spending room you have. It's the difference between "we're fine" and "we need revenue by Q3 or we shut down."
Operators Making Hiring Decisions
You want to hire your first sales person ($80K salary = $6.7K/month when fully loaded). You have $300K cash and $50K burn today. Adding this hire costs $6.7K/month, reducing runway from six months to 5.3 months. That trade-off matters. This calculator quantifies what hiring truly costs in terms of runway compression. Now you can decide: is this hire worth one month of runway?
Finance Teams Presenting to Boards
Investors want to know: how long can you operate? This calculator gives you the answer to present confidently. If you have six months, you also have six months to hit inflection points (product-market fit signals, revenue acceleration, unit economic improvements) that justify a Series A raise. Your runway is your fundraising window.
Tips and Things to Watch Out For
Burn rate changes month to month. Use your average burn rate over the last three months, not just last month. One big vendor payment or hiring in month one doesn't represent your steady state. An average is more reliable than a single data point.
Don't forget the one-time costs. Hiring bonuses, software licenses you purchase annually, conference sponsorships-these create lumpy cash outflows. If you have a $25K annual cost hitting next month, subtract it from your cash on hand or add it to your monthly burn. Steady state is an illusion if you're leaving out annual costs.
Revenue changes the equation. Many founders treat runway as if revenue stays flat. In reality, revenue should be growing (or at worst, staying stable). If you're in early days with zero revenue, use your burn burn number as is. If you have $30K/month revenue growing to $40K next month, factor that in. Runway with growing revenue is longer than the simple formula suggests.
Don't wait until three months to act. A common mistake is to assume "we'll figure something out before runway ends." Don't. When you hit six months of runway, the clock is ticking. Raising capital takes 2-3 months. Cutting costs takes time to execute. Reaching profitability takes months. Act at nine months of runway, not three.
Your burn rate might increase before improving. When you hire a sales team to accelerate growth, burn goes up before revenue does. When you invest in marketing, spend increases immediately but revenue lags. This calculator shows you your current runway, but understand that launching growth initiatives will compress runway in the short term.
Build a buffer into your runway. If your calculator says you have three months, in reality you have about two and a half. External factors (unexpected expenses, slower fundraising, lower revenue) eat into your margin of safety. Don't plan to reach profitability right at month three.
*This runway calculation is based on constant burn rate and revenue assumptions. Real businesses experience seasonality, lumpy expenses, and variable revenue. Recalculate monthly using actual numbers, and build a financial forecast that projects revenue and expenses over time. Consult a CFO or financial advisor for detailed cash flow planning.*
Frequently Asked Questions
Should I include salary I'm not currently taking?
If you could pay yourself a salary but you're not, include it. This shows your "true" burn rate and the cost of the business operating at full capacity. If you're deferring salary because of cash constraints, you're already running leaner than you should, and you need to raise capital or cut costs elsewhere.
What burn rate should I use if I'm growing?
Use your current monthly burn, but note that growth initiatives will increase burn before revenue grows. If you're accelerating hiring or marketing spend, add those costs to your current burn to get a more realistic picture of your near-term runway. It's better to be conservative.
How do I calculate burn rate if I'm profitable?
If you're profitable, your monthly burn is negative-meaning you're adding to cash, not burning it. Your runway is infinite, assuming profitability continues. But even profitable businesses need to watch cash flow. Use this calculator to model "what if we scale and profitability drops?" scenarios.
Should I count venture debt against my runway?
No, not in the simple sense. A $500K venture debt facility doesn't extend your runway if you can't draw on it yet. Count only cash you have today or can access immediately (credit lines you've already arranged). Potential future funding doesn't count.
What's a healthy runway target?
Most VCs want to see at least 18 months of runway when you fundraise. This gives you time to execute your plan, hit metrics, and raise the next round. If you're fundraising with less than 12 months of runway, you're in a weak negotiating position.
How often should I recalculate my runway?
Monthly. Plug in your actual cash and actual burn at month-end, then reforecast. This shows whether your spend is aligned with plan and whether your runway is extending or compressing. Big misses (runway shorter than expected) are signals to cut costs or accelerate fundraising.
What if my runway is only two months?
That's an emergency. You need to either cut burn dramatically (lay off staff, reduce spending by 50%+ immediately), accelerate revenue, or close a fundraise now. Two months is not enough time for a typical capital raise. If you're here, you've waited too long. Act immediately.
Related Calculators
Use the burn rate calculator to break down expenses and revenue to see exactly where cash is flowing. Check the valuation calculator to understand what you might raise and what your runway extension could be. The SaaS metrics calculator helps you forecast revenue growth, which lengthens your runway.