How to Calculate Burn Rate for Your Startup

Burn rate is the one number that quietly decides whether your startup lives or dies. You can have a great product, happy early users, and a clean pitch deck. None of it matters if you wake up one morning and the bank balance is zero.

Here's the uncomfortable part. Most first-time founders can quote their signup numbers from memory but go blank when you ask how much cash they're losing each month. That gap is dangerous. CB Insights looked at hundreds of startup post-mortems and found that running out of cash was the second most common reason companies died, sitting behind only "no market need." Burn rate is how you see that wall coming before you hit it.

So let's fix the gap. This guide walks through what burn rate actually is, the two formulas you need, the difference between gross and net burn, and how to turn the number into a runway figure you can act on. No finance degree required.

What is burn rate?

Burn rate is the speed at which your startup spends cash, usually measured per month. If you start January with $200,000 and end it with $170,000, your burn rate for that month was $30,000. That's it. It's a measure of how fast the tank is draining.

The word "burn" is doing a lot of work here. You're not just spending money, you're consuming a finite resource that took real effort to raise or earn. Every dollar of burn is a dollar closer to either profitability or a fundraise. Founders track it monthly because months are the unit that matters when you're deciding whether to hire, cut costs, or start pitching investors again.

One thing to get straight early: burn rate is about cash, not accounting profit. Your income statement might show a small loss while your bank account drops by far more, because things like prepaid annual software, equipment purchases, and loan payments hit cash differently than they hit your P&L. When you're tracking burn, follow the actual money leaving your account.

How do you calculate burn rate?

The basic burn rate formula is the change in your cash balance divided by the number of months in the period. Take your starting cash, subtract your ending cash, and divide by how many months passed.

Burn rate = (Starting cash balance − Ending cash balance) ÷ Number of months

Say you had $150,000 in the bank on April 1 and $108,000 on July 1. That's a $42,000 drop over three months. Divide by three and your average monthly burn is $14,000. Clean and simple.

Why average across several months instead of looking at one? Because single months lie. You might pay your annual insurance premium in March, which makes March look brutal, then coast through April. Averaging over a quarter smooths out those one-off spikes and gives you a number you can actually plan around. Three months is the sweet spot for most early-stage teams. Long enough to cancel out noise, short enough to stay current.

If you want to sanity-check the number, you can also build it from the bottom up. Add up every recurring cash expense in a typical month: salaries, rent, software subscriptions, contractors, ad spend, hosting. That total is roughly your gross burn, which brings us to the distinction that trips up almost everyone.

What's the difference between gross burn and net burn?

Gross burn is your total monthly cash spending. Net burn is your spending minus the revenue you bring in. The difference between them is whichever number you choose to obsess over, and most founders pick wrong.

Gross burn ignores income entirely. It answers the question, "How much does it cost to keep the lights on each month?" If your company spends $50,000 a month across payroll, rent, tools, and everything else, your gross burn is $50,000, full stop. This is a useful number when you want to understand your cost base or model a worst-case scenario where revenue disappears.

Net burn is the one that actually predicts when you run out of money. It's gross burn minus monthly revenue. Same company, same $50,000 in spending, but now imagine you're pulling in $20,000 a month from customers. Your net burn is $30,000. That's the real rate your bank balance is shrinking.

Here's a quick comparison to make it concrete:

Metric	Formula	Example	What it tells you
Gross burn	Total monthly cash spending	$50,000	Your full cost base
Net burn	Gross burn − monthly revenue	$50,000 − $20,000 = $30,000	How fast cash actually drops

Investors almost always mean net burn when they ask about your burn rate. So do the math on net burn first, then keep gross burn handy for the conversations about cost structure. And if your startup is pre-revenue, your gross and net burn are the same number. There's no income to subtract yet.

How does burn rate connect to runway?

Runway is how many months you can survive at your current net burn before the money runs out. You get it by dividing your cash on hand by your monthly net burn. It's the single most useful thing burn rate gives you.

Runway = Cash in bank ÷ Monthly net burn

If you have $300,000 in the bank and you're burning $30,000 net per month, you've got 10 months of runway. That number changes everything about how you operate. Ten months means you should already be thinking about your next raise or your path to break-even, because fundraising itself eats two to four months. Eighteen months means you have room to experiment. Four months means you're in a sprint, and every decision needs to either cut burn or grow revenue.

A useful habit: recalculate runway every single month, not once a quarter. Burn changes when you hire someone, sign a new office lease, or land a customer. Founders who check runway monthly catch problems while there's still time to react. The ones who check it twice a year tend to discover trouble with six weeks left, which is roughly the worst possible moment to start fixing anything.

This is exactly the kind of number that belongs in your financial model alongside revenue projections and hiring plans. You can run it in a spreadsheet, in a dedicated finance tool, or in a planning platform like Foundra that walks first-time founders through building projections without needing to design the model from scratch. The tool matters less than the discipline of actually keeping the number current.

What's a healthy burn rate for a startup?

There's no universal "good" burn rate, because the only thing that makes burn healthy or unhealthy is what you're getting for it. A $100,000 monthly burn is reasonable for a team of twelve shipping fast and growing revenue 15% month over month. The same burn is reckless for two founders with no users and no clear plan.

The better question is whether your burn is buying progress. Smart money looks at burn multiple, which is net burn divided by net new revenue added in the same period. If you burned $40,000 last month and added $20,000 in new annual recurring revenue, your burn multiple is 2. Lower is better. A burn multiple under 1 is excellent and rare for early companies. Anything above 3 or 4 means you're spending a lot to move the needle a little, and investors will notice.

For most pre-seed and seed-stage startups, the practical guideline is simpler. Keep enough runway that you're never raising from a position of desperation. That usually means maintaining 12 to 18 months of cash and treating any drop below 6 months as a signal to either raise or cut. Plenty of strong companies run lean on purpose. Bootstrapped startups often aim for net burn of zero or close to it, choosing slower growth over the pressure of a ticking clock.

Cash buys you time, and time is the only thing that lets you figure out the business. Protect it like the scarce resource it is.

How can you reduce your burn rate?

You reduce burn by attacking your two biggest cash drains, which for nearly every early startup are payroll and customer acquisition. Trimming software subscriptions feels productive, but canceling a $40 tool while overspending on ads is rearranging deck chairs.

Start with the honest audit. Pull three months of bank statements and tag every recurring charge. Most founders find at least a few hundred dollars a month in tools nobody uses, duplicate subscriptions, and services they meant to cancel. That's the easy win, and it's worth doing, just don't stop there.

The bigger levers take more nerve. Hiring is the largest commitment most startups make, so delaying a hire or using contractors for non-core work can extend runway by months. Renegotiating annual contracts often unlocks a discount of 10% to 20% if you simply ask. And on the revenue side, raising prices or focusing your sales effort on customers who pay faster shrinks net burn without cutting a single expense, because remember, net burn falls when revenue rises just as surely as when costs drop.

One word of caution. Cutting burn to zero by freezing all spending can starve the very growth that justifies your existence. The goal isn't the lowest possible burn. It's the burn rate that buys you the most progress per dollar while keeping comfortable runway. Sometimes the right move is to spend more, faster, because you've found something that's working.

How often should you track burn rate?

Track burn rate monthly, every month, without exception. Cash flow shifts faster than founders expect, and a number you checked in March tells you almost nothing about where you stand in June. Monthly tracking is the baseline, not a stretch goal.

The mechanics are easy. At the close of each month, write down your ending cash balance, your gross burn, your revenue, your net burn, and your updated runway in months. Keep these in a running sheet so you can see the trend, because the direction matters as much as the absolute number. Burn creeping up three months in a row is a story your single-month snapshot will never tell you.

If you raise money or make a big hire, recalculate immediately rather than waiting for month-end. A new salary or a fresh check in the bank changes your runway the moment it happens, and you want your numbers to reflect reality. This sort of ongoing financial tracking pairs naturally with the rest of your planning work, and you can find more frameworks for it in the guides at foundra.ai/key-reads/.

Key takeaways

• Burn rate is how fast you spend cash, usually measured per month, calculated as the change in your cash balance over a period divided by the number of months.
• Gross burn is total spending. Net burn subtracts revenue. Net burn is the number that predicts when you run out of money, and it's what investors mean when they ask.
• Runway equals cash divided by net burn. It tells you how many months you have left, and you should recalculate it monthly.
• Healthy burn is relative. Judge it by the progress it buys, using metrics like burn multiple, and aim to keep 12 to 18 months of runway.
• Cut burn by attacking payroll and acquisition first, not tiny subscriptions, and remember that growing revenue lowers net burn just as well as cutting costs.

The founders who survive aren't the ones who never lose money. They're the ones who always know exactly how much they're losing and how long they've got. Burn rate is that knowledge. Calculate it, track it monthly, and it stops being a source of anxiety and becomes a steering wheel.

Frequently asked questions

What is a good monthly burn rate for an early-stage startup?
There's no fixed number, because a good burn rate depends on what it buys. A useful guideline is to keep 12 to 18 months of runway and treat dropping below 6 months as a signal to raise or cut. Judge burn by progress, not by the dollar amount alone.

Is burn rate the same as net loss?
No. Net loss is an accounting figure from your income statement, while burn rate measures actual cash leaving your bank account. They differ because items like prepaid expenses, equipment purchases, and loan principal affect cash and accounting profit on different schedules. Always track burn from your real cash balance.

How do you calculate runway from burn rate?
Divide your cash in the bank by your monthly net burn. If you have $240,000 and burn $20,000 net per month, you have 12 months of runway. Recalculate it every month, since hiring, new revenue, and one-off costs all shift the number.

What is gross burn versus net burn?
Gross burn is your total monthly cash spending with no income subtracted. Net burn is gross burn minus your monthly revenue, which shows how fast your cash actually drops. Pre-revenue startups have identical gross and net burn because there's no income to subtract.

Can a startup have a negative burn rate?
Yes. A negative burn rate means your company is cash-flow positive, bringing in more money than it spends, so your bank balance grows each month. This is sometimes called "default alive." It's the goal for bootstrapped startups and a strong position for any company heading into a fundraise.

How do I lower my burn rate without hurting growth?
Focus on your biggest cash drains first, which are usually payroll and customer acquisition, and cut waste like unused subscriptions. Then look at raising revenue, since net burn falls when income rises. Avoid slashing spending so hard that you starve the growth that justifies the company.