Finance Fundamentals

Burn Rate Formula: Gross Burn, Net Burn, and Runway

Master the exact formulas every investor and CFO uses to calculate burn rate, net burn, runway, and the burn multiple — plus 8 proven tactics to reduce your monthly spend.

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Burn rate is one of the most scrutinized numbers in startup finance. Every investor will ask about it. Your board will want it on every slide. And frankly, knowing it — and knowing it precisely — is essential to making good decisions about hiring, fundraising, and growth investment.

This guide explains the exact formulas, shows worked examples, introduces the burn multiple (a newer metric investors care deeply about), and gives you 8 concrete tactics to reduce burn when you need to extend runway.

$50–150K
Median monthly burn at Series A
18+ mo
Ideal runway after a raise
<1.5×
Target burn multiple for top-quartile startups

Gross Burn Rate Formula

Gross burn rate is the total amount of cash your company spends in a given month — before subtracting any revenue. It represents your full operating cost.

Gross Burn Rate = Total Monthly Cash Outflows

What goes into gross burn? Every dollar that leaves your bank account: payroll and benefits, rent and utilities, software subscriptions, cloud infrastructure, marketing spend, legal and accounting fees, travel, and any other operating expenses.

Gross Burn Example

Suppose your startup has the following monthly expenses:

Expense CategoryMonthly Amount
Payroll & benefits (8 employees)$72,000
Office & utilities$4,500
SaaS tools & software$3,200
AWS / cloud infrastructure$6,800
Marketing & ads$8,000
Legal & accounting$2,500
Other operating expenses$3,000
Total Gross Burn$100,000

Net Burn Rate Formula

Net burn rate subtracts your revenue from your gross burn. This is the number that actually determines how fast you're depleting your cash — and therefore how long your runway is.

Net Burn Rate = Gross Burn − Monthly Revenue (Cash Received)

Note: use cash received, not recognized revenue. If you're on accrual accounting, a customer might be recognized in your P&L before they've actually paid you. For burn rate purposes, use the actual cash that hit your bank account.

Net Burn Example

Using the same company above, with $35,000 in monthly recurring revenue actually collected:

Net Burn = $100,000 − $35,000 = $65,000/month

Runway Formula

Runway is the number of months until your company runs out of cash at the current burn rate. Always calculate runway using net burn (not gross burn), since revenue is extending your life.

Runway (months) = Cash on Hand ÷ Net Burn Rate

Runway Example

If you have $780,000 in the bank and a net burn of $65,000/month:

Runway = $780,000 ÷ $65,000 = 12 months

Twelve months of runway means you need to either reach profitability, close a new round, or materially reduce burn within the next 6–9 months (to account for fundraising lead time).

The Burn Multiple Explained

The burn multiple is a metric popularized by David Sacks and widely used by VCs to evaluate capital efficiency. It measures how many dollars you burn for every dollar of net new ARR you generate.

Burn Multiple = Net Burn ÷ Net New ARR Added

A lower burn multiple is better. If you burn $65,000 to add $65,000 in new ARR (on an annualized basis, so ~$5,400/month), that's a burn multiple of roughly 12 — very high. If you add $100,000/month in new MRR ($1.2M ARR annualized), that's a burn multiple of 0.65 — excellent.

Burn MultipleInvestor Signal
Below 1×Outstanding — extremely capital efficient
1× – 1.5×Good — healthy growth efficiency
1.5× – 2×Acceptable — watch closely
2× – 3×Concerning — growth is expensive relative to output
Above 3×Red flag — fundamental unit economics problem

What's a "Good" Burn Rate at Each Stage?

Burn rate benchmarks vary significantly by stage, team size, and business model. Here are rough ranges to orient your expectations:

What matters more than absolute burn is whether your burn multiple is improving as you scale. A startup burning $500K/month and adding $600K in net new ARR is in a much stronger position than one burning $150K and adding $80K in ARR.

Calculate Your Burn Rate and Runway Instantly

Enter your monthly expenses and revenue into CFOTechStack's free burn rate calculator and get your gross burn, net burn, runway, and burn multiple — all in one place.

Use the Free Burn Rate Calculator →

8 Tactics to Reduce Your Burn Rate

When you need to extend runway, these are the highest-leverage levers — roughly in order of impact and reversibility:

  1. Reduce headcount or pause hiring — Payroll is typically 60–80% of startup burn. Even a hiring freeze meaningfully flattens the burn trajectory. This is the hardest lever emotionally, but the most impactful financially.
  2. Audit and cut SaaS subscriptions — Most companies are paying for 20–40% more software than they actively use. A one-day audit of all recurring charges can yield $5K–$30K/month in savings with zero impact on operations.
  3. Renegotiate vendor contracts — AWS, Salesforce, and most enterprise vendors will negotiate, especially for multi-year commitments or during contract renewals. It's common to save 20–40% by simply asking.
  4. Shift variable spend to performance-based — Convert fixed marketing spend to performance channels where you only pay for results. This makes burn variable (scaling with revenue) rather than fixed.
  5. Accelerate collections — Shorten payment terms, offer early-pay discounts, and automate invoice follow-up. Reducing DSO from 45 days to 20 days can meaningfully improve your cash position without reducing revenue.
  6. Push annual prepay deals — Offer customers a 10–15% discount for paying annually upfront. This converts future MRR into immediate cash and reduces churn risk simultaneously.
  7. Defer discretionary capex — Office upgrades, non-critical equipment purchases, and conference sponsorships can almost always be deferred 6–12 months without operational impact.
  8. Explore non-dilutive financing — Revenue-based financing, venture debt, and R&D tax credits are all ways to extend runway without giving up equity. Many startups leave significant capital on the table by not exploring these options.

Burn Rate vs. Run Rate: Don't Confuse Them

Run rate is an annualized projection of your current revenue (e.g., if you earned $100K in MRR last month, your ARR run rate is $1.2M). Burn rate is about cash out. They're related — a higher revenue run rate means lower net burn — but they're measuring different things. Investors want to see both, and they want them improving in the right directions simultaneously.

Frequently Asked Questions

Should I use gross burn or net burn for investor conversations?
Use both and be explicit about which you're citing. Gross burn tells investors your total cost structure. Net burn tells them how fast you're actually depleting capital. Leading with net burn without explaining gross burn can obscure whether your cost structure is sustainable. Present gross burn, net burn, and runway together for a complete picture.
How do I calculate burn rate if my expenses vary month to month?
Use a 3-month trailing average. Sum your total cash outflows for the last 3 months and divide by 3. This smooths out one-time expenses (like an annual insurance payment or a quarterly tax installment) and gives a more representative picture of your ongoing burn trajectory. For forecasting, build a month-by-month model rather than assuming a flat average.
What's the difference between burn rate and cash flow?
Burn rate is specifically the net cash consumed per month (for pre-profitable companies). Cash flow is a more general term that can be positive or negative and applies at any profitability stage. Once a company becomes cash-flow positive, "burn rate" is no longer a relevant metric — the focus shifts to operating cash flow, free cash flow, and working capital management.
How does burn rate affect my fundraising valuation?
High burn relative to growth (a poor burn multiple) signals capital inefficiency, which can suppress your valuation or make raising harder entirely. Investors running a DCF-style analysis will also factor in how much additional capital you'll need to reach milestones — higher burn means more dilution ahead. In a tighter fundraising environment, burn multiple has become as important as growth rate for many investors.
Is a zero burn rate always the goal?
No. A zero burn rate (breakeven) is not inherently optimal for a high-growth startup. The question is whether your burn is generating commensurate value — i.e., whether the ARR you're adding justifies the cash you're consuming. A burn multiple of 1.0 means you're spending $1 to create $1 of ARR, which is often very good at early stages. The goal is efficient growth, not minimal spend.