Burn Rate & Runway Calculator
Calculate your startup's gross burn, net burn rate and cash runway instantly. UK benchmarks for founders and investors.
Last updated: March 2026
UK Startup Burn Rate Calculator
Enter your monthly revenue, total expenses and current cash balance to calculate burn rate and runway
UK Startup Burn Rate Benchmarks 2025/26
Typical Monthly Burn by Funding Stage
| Stage | Typical Raise | Gross Burn/Month | Team Size |
|---|---|---|---|
| Pre-seed / Bootstrapped | £0–£250K | £5,000–£15,000 | 1–3 people |
| Seed | £500K–£2M | £20,000–£50,000 | 4–10 people |
| Series A | £5M–£20M | £100,000–£300,000 | 15–50 people |
| Series B | £20M–£60M | £300,000–£1M+ | 50–200 people |
Burn Multiple Benchmarks (New ARR Generated Per £ Burned)
| Burn Multiple | Assessment | What It Means |
|---|---|---|
| Below 1x | Excellent | Burning less than £1 to generate £1 of new ARR |
| 1x – 1.5x | Good | Efficient growth, most UK VCs will be interested |
| 1.5x – 2x | Acceptable | Early stage, manageable if growth rate is strong |
| Above 2x | Concerning | Burning too much relative to growth generated |
Gross Burn Rate vs Net Burn Rate: What’s the Difference?
Understanding the distinction between gross and net burn rate is fundamental for any UK startup founder or investor. Gross burn rate is the total amount of cash your company spends every month across all categories — payroll, rent, cloud infrastructure, marketing, professional fees, and every other outgoing. It is a measure of your cost base and operational footprint.
Net burn rate is your gross burn minus your monthly revenue. This is the figure that actually determines how fast your cash balance is declining. If you spend £60,000 per month and generate £20,000 in revenue, your net burn is £40,000 per month — and this is the number you divide into your cash balance to calculate runway.
Investors look at both. Gross burn tells the story of your cost structure and scalability. Net burn and the trajectory of net burn (is it improving month-on-month as revenue grows?) tells the story of your path to profitability. A seed-stage startup burning £40,000 per month gross with £0 revenue is in a very different position from one burning £40,000 per month gross with £35,000 in revenue — the latter has a net burn of just £5,000 and is approaching breakeven.
How to Calculate Your Cash Runway
Cash runway is simply how many months of operation your current cash reserves will fund. The formula is:
Runway (months) = Current Cash Balance ÷ Net Burn Rate
For example, if your startup has £600,000 in the bank and your net burn rate is £50,000 per month, you have 12 months of runway. Always model conservative scenarios (higher burn assumptions) alongside optimistic ones.
UK VCs typically expect founders to have at least 12 months of runway remaining when they begin a fundraising process. A UK seed-to-Series-A fundraise takes 4–6 months from first meetings to cash in the bank; Series A takes 6–9 months. Founders should begin fundraising conversations at the 12–15 month runway mark at the latest.
The Rule of 40 and Burn Multiple
Burn rate alone does not tell the full story of startup efficiency. Two additional metrics help contextualise it:
The Rule of 40 states that a healthy SaaS company’s revenue growth rate (expressed as a percentage) plus its profit margin should equal or exceed 40. A startup growing at 80% annually with a −20% profit margin scores 60 — excellent. One growing at 15% with a −30% margin scores −15 — concerning. UK VCs want to see this score improving over time.
Burn multiple, popularised by David Sacks, measures how efficiently you convert cash burn into new Annual Recurring Revenue (ARR). Formula: Net Burn ÷ New ARR Added. If you burned £500,000 in a quarter and added £600,000 in new ARR, your burn multiple is 0.83x — exceptional. UK Series A investors in 2024–25 typically look for burn multiples below 2x before leading a round.
How to Extend Your Startup Runway in the UK
When runway is under pressure, UK founders have several levers to extend it before resorting to emergency fundraising:
1. Claim R&D Tax Credits. UK companies investing in qualifying research and development can claim the RDEC — a 20% above-the-line credit on qualifying spend. For a startup spending £30,000/month on qualifying R&D (developer salaries, cloud computing), this yields around £72,000 in annual cash credits from HMRC. Many early-stage UK founders leave this unclaimed.
2. Apply for Innovate UK grants. Innovate UK provides non-dilutive funding of £25,000–£2M+ for qualifying UK technology companies through Smart Grants, the Sustainable Innovation Fund, and sector-specific programmes.
3. Renegotiate supplier contracts. Office leases, SaaS subscriptions, and service contracts often have room for renegotiation, especially if you commit to longer terms. Many UK landlords will offer 3–6 months rent-free in exchange for longer lease commitments.
4. Accelerate revenue collection. Offer annual prepayment discounts (10–15% off for paying 12 months upfront). This converts future cash inflows into immediate runway extension — a common UK B2B SaaS tactic.
5. Use revenue-based financing. UK lenders such as Uncapped, Capchase, and Clearco offer non-dilutive financing against future revenue for startups with £30K+ monthly recurring revenue, providing £100K–£5M without triggering a full funding round.
Default Alive vs Default Dead: Paul Graham’s Framework
Paul Graham of Y Combinator introduced the concept of default alive and default dead. A company is default alive if, assuming no change in growth rate and no additional investment, it will reach profitability before its cash runs out. Default dead means the opposite: at current trajectory, you will exhaust cash before reaching breakeven.
Most seed-stage UK startups are default dead — intentionally investing ahead of revenue to capture market share. This is acceptable and expected. The critical insight is that founders should know their status at all times. Knowing you are default dead with 8 months of runway gives you time to act. Not knowing until month 3 leaves you no options.
UK VCs assessing whether to lead an emergency round will want to see that the founder understands their default alive/dead status, has a credible path to extending runway, and is not in denial about the severity of the situation.
UK VC Expectations: When to Fundraise
The leading UK venture investors — including Balderton Capital, Index Ventures, Octopus Ventures, and Seedcamp — broadly align on the following principles:
Start fundraising at 12–15 months of runway. This gives you buffer time to run a competitive process without desperation pricing. Founders who raise with 6 months left accept worse terms; those with 18 months have negotiating leverage.
Target 18–24 months of post-raise runway. After a round closes, experienced founders model the new capital lasting 18–24 months to the next milestone (typically 3x–5x revenue growth). Raises that provide only 12 months of runway leave insufficient time to reach the next inflection point.
UK round sizes in 2025. Median UK seed rounds are £750K–£2M at pre-money valuations of £3M–£8M. Series A rounds are typically £5M–£20M at valuations of £15M–£60M. Deep tech, climate, and defence startups often raise larger rounds at earlier stages due to capital intensity.