A founder with $360,000 in the bank and a team of five feels comfortable. Eight months later, that same founder is scrambling for a bridge round because they never did the math. The burn rate formula is the single most important calculation in early-stage finance, and founders who don't know their number by heart are already in trouble.
Burn rate tells you how fast your company spends money. Runway tells you how long that money lasts. Together, they dictate when you need to raise, when you need to cut, and whether your current plan is survivable. Every conversation with investors, every hiring decision, and every product timeline depends on these two numbers.
How to Calculate Burn Rate
Burn rate comes in two flavors: gross and net. You need both.
Gross burn rate is your total monthly spending, regardless of revenue. The formula:
Gross Burn Rate = Total Monthly Operating Expenses
If your startup spends $15,000 on salaries, $3,000 on software and infrastructure, $2,000 on office space, and $5,000 on contractors, your gross burn rate is $25,000 per month. That's it. Add up everything that leaves the bank account in a given month.
Net burn rate accounts for revenue. The formula:
Net Burn Rate = Total Monthly Operating Expenses - Total Monthly Revenue
If that same company brings in $8,000 per month from early customers, the net burn rate drops to $17,000. Net burn is the number that actually determines how fast your cash disappears.
Most founders should track both. Gross burn rate shows your cost structure. Net burn rate shows your actual cash consumption. When investors ask about your burn rate, they typically mean net, but they'll want to see gross too because it reveals how much of your spending is fixed versus discretionary.
Burn Rate & Runway Calculator
Interactive Tool
Startup Runway Calculation
Runway is the amount of time your company can operate before running out of cash. The formula:
Runway (months) = Cash on Hand / Net Burn Rate
A startup with $360,000 in the bank and a net burn rate of $45,000 per month has exactly 8 months of runway. That sounds like a lot until you consider that a typical fundraising process for a seed round takes 3 to 5 months. If that founder waits until month 4 to start raising, they'll be negotiating from a position of desperation by month 7.
Here's a practical example. Say you just closed a pre-seed round of $500,000:
- Team: 2 founders (no salary yet), 1 engineer ($9,000/mo), 1 part-time designer ($3,000/mo)
- Infrastructure: AWS, Vercel, analytics tools ($1,200/mo)
- Office/misc: Co-working space, insurance, legal retainer ($2,800/mo)
- Gross burn rate: $16,000/mo
- Revenue: $0 (pre-product)
- Net burn rate: $16,000/mo
- Runway: 31 months
That's a strong position. The founders can spend 12 to 15 months building and validating before they need to think about the next round. Compare that to a company that immediately hires five people and pushes gross burn to $65,000/mo: their runway shrinks to 7.7 months, and the pressure to raise again starts almost immediately.
Gross Burn Rate vs Net Burn Rate: When Each Matters
Gross burn rate matters most during three moments:
- Before you have revenue. Pre-revenue startups have identical gross and net burn rates. Every dollar of spending is a dollar of cash consumed.
- When planning cuts. If you need to extend runway, gross burn shows you the full picture of where money goes. You can't cut what you can't see.
- When investors evaluate your cost structure. A company with $50,000 in monthly revenue and $120,000 in gross burn tells a different story than one with $50,000 in revenue and $60,000 in gross burn, even though both have the same net burn of $70,000 and $10,000 respectively.
Net burn rate matters for everything else: fundraising timelines, board updates, financial projections, and the daily question of whether your plan is working.
What Good Burn Rate Looks Like by Stage
There's no single "right" burn rate. It depends on your stage, your funding, and your market. Here are reasonable benchmarks based on what we see across the Startup Science platform:
StageTypical Monthly BurnTypical Runway TargetPre-seed$10,000 to $30,00018 to 24 monthsSeed$30,000 to $80,00015 to 20 monthsSeries A$80,000 to $250,00018 to 24 months
These are ranges, not rules. A pre-seed startup in San Francisco with three engineers will burn more than one in Austin with two. The point isn't to hit a specific number. The point is to maintain enough runway that you're making decisions from a position of choice, not panic.
A useful rule of thumb: after closing a round, you should have at least 18 months of runway. Less than 12 months means you're essentially in continuous fundraising mode, which splits your attention and weakens your negotiating position. Gregory Shepard's research across 2,200+ founder interviews consistently shows that startups with less than 12 months of post-raise runway are 3x more likely to accept unfavorable terms on their next round.
Burn Rate Benchmarks by Stage
What Good Looks Like
Five Ways to Manage Your Burn Rate
Knowing your burn rate formula is step one. Managing it is the real work.
1. Review monthly, not quarterly. Burn rate drifts. A new tool here, a contractor extension there, and suddenly you're spending $8,000 more per month than you planned. Monthly reviews catch drift before it compounds.
2. Separate fixed from variable costs. Salaries, rent, and software subscriptions are fixed. Contractors, ad spend, and travel are variable. When you need to extend runway, variable costs are the first lever. You can pause a marketing campaign in a week; you can't undo a hire that fast.
3. Model scenarios at different revenue levels. Build a simple spreadsheet with three columns: current state, pessimistic (revenue drops 30%), and optimistic (revenue grows 50%). Recalculate runway for each. If your pessimistic scenario puts you under 6 months of runway, you need a contingency plan before you need to use it.
4. Start fundraising with 9+ months of runway. Fundraising takes longer than founders expect. Series A rounds can take 4 to 6 months from first meeting to wire. If you start with only 6 months left, you'll lose your negotiating position before you run out of cash.
5. Track burn rate as a company health indicator. Your traction metrics dashboard should include burn rate right alongside MRR, CAC, and retention. Every person on your team should understand the number and what it means for their decisions.
Common Burn Rate Mistakes
Ignoring founder salaries. Many early founders skip their own compensation in burn rate calculations. This works until it doesn't. If you plan to start paying yourself $6,000/mo in six months, that cost belongs in your projected burn rate today, not as a surprise later.
Counting committed revenue as cash. A signed contract isn't money in the bank. Annual contracts with quarterly payment terms, pilot programs with 60-day payment windows, and enterprise deals that take 90 days to process all create gaps between revenue on paper and cash you can spend. Use actual cash received, not booked revenue.
Cutting too late. Founders delay layoffs and spending cuts because they're painful. The math doesn't care about comfort. If your runway drops below 6 months and you don't have a term sheet in hand, you should have already made cuts. Waiting until month 4 to act on a problem you saw at month 8 is how startups die.
Frequently Asked Questions
What's the difference between burn rate and runway?
Burn rate measures how much cash your company spends per month (either gross or net). Runway measures how many months of operation that cash will cover. Burn rate is the speedometer; runway is the fuel gauge.
How often should I recalculate my burn rate?
Monthly at minimum. Recalculate whenever you add a team member, close a new revenue contract, or make a spending change over $1,000/mo. Some founders review weekly during periods of rapid growth or cost change. If you're preparing to raise funding, recalculate the week before any investor meeting.
Is a high burn rate always bad?
No. A high burn rate paired with strong revenue growth and clear unit economics can be a sign of a company investing aggressively in a proven model. A high burn rate with no revenue and no product-market fit signals that a company is spending money it shouldn't be. Context determines whether the number is healthy or dangerous.
Should I include one-time expenses in burn rate?
Exclude true one-time costs (legal fees for incorporation, a single conference sponsorship) from your monthly burn rate calculation. They distort the trend line. Track them separately as "non-recurring expenses" so your burn rate reflects your actual ongoing cost structure. If a "one-time" expense keeps happening every quarter, it's not one-time.
How do I present burn rate to investors during a funding round?
Lead with net burn rate and current runway. Then show gross burn alongside revenue to demonstrate your cost structure. Investors want to see that you know your numbers cold and that your spending matches your stage. A pre-seed company burning $80,000/mo with no revenue will raise questions. The same burn rate at Series A with $40,000/mo in growing revenue tells a completely different story.
