How Much Runway Should a Startup Have? The 2026 Seed Answer

How much runway should a startup have after a seed round? Most pages that rank for this question say 12 to 18 months, and a few still say 6 to 12. Those ranges assume a fast path to Series A. Current data shows a slower path and a higher bar, so a seed company that plans for 18 months often starts raising from a weak position. This guide builds a runway target from recent numbers, shows you how to calculate runway so it holds up, and walks through a worked example.

The Short Answer: Plan for 24 to 30 Months at Close

Close your seed round with enough cash to cover 24 to 30 months at your planned burn, and start your Series A process when about 12 months remain. BurnRateIQ builds that target from three parts: the time it takes to reach Series A, the time it takes to run the raise, and a buffer for things that slip.

The first part comes from Carta's Q2 2025 Series A report. Carta found that US startups on its platform waited a median of 616 days between a seed round and a Series A in Q2 2025, a little more than 20 months. That wait grew by more than two months compared with two years earlier. Add 3 to 6 months to run a fundraising process and 1 to 4 months of buffer, and you get 24 to 30 months. BurnRateIQ built this planning rule on Carta's median, so adjust it for your own milestones.

Why Did 18 Months Stop Being Enough?

The 18-month rule assumed you could hit your Series A milestones in about a year and still have six months to raise. Carta's data breaks that assumption in three ways:

1. The wait got longer. The median seed-to-Series A gap reached 616 days in Q2 2025, according to Carta. An 18-month runway ends before the median company closes its A.
2. Investors do fewer deals. Carta counted 18% fewer Series A deals in Q2 2025 than a year earlier, and total Series A cash fell 23% to $4.7B. Compared with Q2 2022, quarterly Series A cash was down 54% and deal count was down 34%.
3. The bar went up. The median Series A pre-money valuation hit a record $47.9M in Q2 2025, and the 75th percentile topped $80M, per Carta. In the same report, one investor at Fiat Ventures said the firm now expects $5M to $10M of ARR at Series A, up from about $1M two or three years ago. That is one firm's view, but it matches the direction of the deal data.

Now run that higher bar through growth data. In the benchmark library BurnRateIQ curates, Benchmarkit's 2025 B2B SaaS benchmarks show a median annual ARR growth rate of 100% for companies under $1M ARR (25th percentile 80%, 75th percentile 150%) and a median of 45% for companies between $1M and $5M ARR. A company at $1M ARR that doubles every year needs about 28 months to pass $5M. If growth slows toward that 45% median, it takes longer still. Either way, the math outruns an 18-month runway.

How to Set Your Own Runway Target

Use the median as a starting point, then replace it with your own numbers:

1. Estimate the months until you hit your Series A milestones. Start from Carta's median of about 20 months (Carta) and check it against your plan. If your Series A needs a revenue level your current growth rate reaches in 26 months, use 26.
2. Add 3 to 6 months for the raise. First meetings, partner meetings, diligence and legal close all take time, and a slow market stretches each step.
3. Add 1 to 4 months of buffer. Use the low end if your revenue is predictable and the high end if one large deal or one key hire drives your plan.
4. Convert months into dollars with your forecast burn. Multiply the target months by your planned average monthly spend, including every hire on your plan. The guide on how much a startup should raise covers this sizing step.
5. Set your fundraising start date. Count back 12 months from your forecast cash-zero date and put that month on the calendar.

The table below applies the BurnRateIQ formula with Carta's 20-month median as the base (Carta).

How Do You Calculate Runway So the Number Holds Up?

Runway in months equals cash on hand divided by average monthly net burn. Kruze Consulting shows the method with a three-month average: ($740K + $820K + $910K) ÷ 3 = $823,333 of monthly burn, and $15M ÷ $823,333 gives about 18 months. The average smooths out a month with an annual software bill or a large customer payment.

Use net burn, cash going out minus cash coming in, as the denominator. Indinero shows how much the choice matters: on the same balance sheet, its example drops from 15.0 months on net burn to 5.8 months on gross burn. Gross burn still has a job. It tells you what the business costs if revenue stalls, which makes it a useful stress test when you size a seed round.

Two more rules keep the number honest. Count only the cash in your bank account, since receivables and unsigned term sheets can't pay payroll. Then turn runway into a calendar date: your zero-cash date is today plus your runway. The full walkthrough lives in how to calculate startup runway.

My take: Measure burn on the average of the last three months, never one month. And watch forecast runway, the month cash hits zero once your hiring plan kicks in, more closely than today's runway. Today's number flatters you if you plan to hire.

How Much Runway Do Startups Actually Have?

Most funded startups run with far less than 24 months. Kruze Consulting reports that its VC-backed clients averaged about 22 months of runway heading into 2024, with a median of almost 12 months. That gap suggests a few well-funded companies pull the average up while the typical company sits near a year.

The share of Kruze clients with less than six months of runway stayed between 36% and 42% every year from 2019 through 2023, per the same Kruze report. In good markets and bad, more than a third of these startups sat within six months of zero cash.

When Should You Start Raising Your Series A?

Start your process with about 12 months of runway left. That covers the 3 to 6 months a raise takes and leaves time to recover if the first round of meetings goes badly. If you wait until 6 months remain, investors can see your zero-cash date as clearly as you can, and your leverage drops.

Paul Graham's essay on default alive or default dead gives you a second test. Assume your expenses stay flat and your revenue keeps growing at its recent rate. If you reach profitability on the cash you have, you are default alive. If you don't, you depend on the next round, and you need to know that early.

My take: Start raising with about 12 months of runway left. Under 6 months, cut costs first. A company that has already extended its runway raises from a stronger position than one racing the clock.

Example: Sizing Runway for a Fictional Seed SaaS Company

Tallyline is a fictional B2B SaaS company that just closed its seed round. It has $4.5M in the bank. Its gross burn over the last three months was $200K, $205K and $225K, an average of $210K. It brings in $40K of monthly recurring revenue, so its net burn is $170K.

Today's runway looks comfortable: $4.5M ÷ $170K = 26.5 months. On gross burn, runway is $4.5M ÷ $210K = 21.4 months.

Tallyline's plan adds five hires over the next nine months, which raises gross burn to $290K by month nine. Revenue grows to $90K MRR by month 12. In the full monthly forecast, average net burn comes to about $230K, and forecast runway falls to 19.6 months. Cash hits zero in month 20, so the founders would need to start raising in month 8, long before they reach a Series A revenue level.

The founders test two fixes. Delaying two hires by six months cuts average net burn to about $196K and stretches runway to 23.0 months. Raising more also works: 26 months at $230K of average net burn needs about $6.0M, or $1.5M more than they closed.

Each scenario takes one row change in a live-formula model. You can build the same forecast from your own books with a one-time investor-ready Excel model, where every hire has a start date and a salary and investors can audit every formula.

How Can You Extend Runway Without Raising?

If your forecast runway falls short of your target, these levers move it fastest:

1. Push out planned hires. Salaries are usually the largest line in a seed budget, and you control each start date.
2. Collect cash sooner. Offer annual prepaid plans so customers pay up front.
3. Fix retention before buying growth. Churn comes straight out of net new ARR, so a company with high churn has to sell more just to stand still. In the benchmark library BurnRateIQ curates, SaaS Capital's 2025 retention benchmarks put median annual gross churn at 10% and median net revenue retention at 101% for equity-backed companies.
4. Track efficiency. Your burn multiple shows how much cash you spend for each dollar of new ARR and flags spend that isn't producing growth.

Your runway target depends on your burn, your hiring plan and your Series A milestones. Connect Xero, Zoho Books or FreshBooks to BurnRateIQ, or answer six quick questions, to see your forecast runway, cash-zero date and fundraising start month. You can try it on sample numbers in the live demo first.