Plan Runway for 2.5 Years: What Carta Data Says About Round Timing

The old cadence no longer fits

Many founders still plan around the classic rhythm: raise, build for 18 months, raise again. Carta's data says that rhythm describes a shrinking slice of the market.

In a November 2025 post, Carta's Insights lead Peter Walker reported that the median time between rounds is now above two years for Seed to Series A, Series A to B and Series B to C. At the 75th percentile, the gap runs above 3.5 years at all three transitions. Headlines about AI-native companies raising every six months, he wrote, describe a tiny fraction of VC-backed companies.

Carta's Q2 2025 bridge-round analysis puts a number on it: the median interval between primary (priced) rounds was 696 days, about 23 months. Two years earlier it was nearly 600 days, roughly three months shorter. For seed-stage companies specifically, Carta found the median time from Seed to Series A was 2.1 years in 2024.

The practical point: if your plan assumes the next round arrives on a fixed schedule, the median company is already running later than that schedule.

Bridges are the pressure valve, and they are common

When the next priced round slips, companies bridge. Carta's analysis found bridge rounds made up 16.6% of all cash raised on its platform in Q2 2025, up from 11.8% in Q2 2024. In 2021, bridges typically stayed under 10% of cash raised per quarter. At Series A, 22.5% of cash came from bridges in Q2 2025.

On the seed-to-A path, Carta reported that 32% to 36% of companies raise bridge capital before their next primary round. About half of those 2024 bridges were priced equity and about half were SAFEs or convertible notes.

A bridge is not a failure, but it carries costs the headline number hides. It adds a second negotiation, more dilution and often a signaling question for the next lead: why did the company need more cash before the planned milestone? Treat a bridge as a tool you may use, not as the plan.

What the current medians look like

Carta's July 2026 benchmark covers more than 1,000 software rounds raised in the prior six months, excluding bridges and extensions. All companies in the sample use Carta cap tables, and Carta says at least half would likely count as AI-native. Medians:

Stage	Post-money valuation	Amount raised	Dilution
Seed	$24.3M	$4.1M	18%
Series A	$80M	$14.4M	18%
Series B	$191M	$25M	12%
Series C	$391M	about $40M	under 10%
Series D	$789M	$63M	8%

Carta is explicit that these are a rough reference, not a target, and that each deal is different. It also notes that valuation largely follows from how much cash you raise and how much dilution you accept. Large valuations usually come with large raises, so the question to ask first is how much cash the plan actually needs.

A runway-first way to size the raise

Start from time rather than from price. Walker's earlier guidance was that a founder should plan for at least 2.5 years of runway from a raise, and that raising every 18 to 24 months is a risky cadence. That is his recommendation, not a measured outcome, but it lines up with the interval data above.

Here is one way to turn that into a working number. The arithmetic below is an illustration, not Carta data.

Pick the runway. Take 30 months as the target, which matches the 2.5-year guideline.
Divide the round by the runway. At the median seed of $4.1M, 30 months means an average spend of roughly $137,000 a month. At the median Series A of $14.4M, it means roughly $480,000 a month.
Compare that to your real plan. If your hiring plan burns well above that figure, you have two honest choices: raise more and accept more dilution, or cut the plan so the money lasts as long as the market's typical gap between rounds.
Set the trigger date. Count back from the day cash runs out. Leave room for the process itself: starting well before the balance gets uncomfortable keeps you negotiating from choice rather than need.

The 18% median dilution at both Seed and Series A is a useful sanity check. If your model requires giving up far more than that to fund 30 months, either the plan is large for the stage or the valuation expectation is high relative to peers. Neither is disqualifying, but you should know which one you are in before the first investor call.

What investors will ask next

A runway-first plan also makes outreach easier. Investors want to know what the money buys and what the company will have proven when it next needs capital. A raise sized to 30 months lets you state milestones that fit inside the window, and it shows you have already thought about the case where the next round takes longer than the median.

Expect questions along these lines:

What are the two or three milestones this round funds, and by what month do you expect each?
What does the company look like at month 18 if growth is half of plan?
Which costs can be cut, and how fast, if the next round slips?
If you need a bridge, who among current investors has pro rata rights and the capacity to participate?

Having those answers in the deck appendix or data room saves a week of back and forth later.

What to watch

Three data points will show whether the longer cadence persists. First, whether Carta's median interval between primary rounds keeps rising past 696 days in later quarters. Second, whether the bridge share of cash raised stays above the sub-10% level typical of 2021. Third, whether seed and Series A dilution, both at 18% in the July benchmark, holds or moves as large rounds in AI-heavy segments pull the medians.

Carta notes that medians reflect a wide range and that at least half the sample is likely AI-native. Founders outside that group should read the medians cautiously and build the plan from their own cash needs.

The takeaway is simple. The market's timetable is slower than the folk wisdom, so the safest raise is the one sized to outlast it.

This post is information and commentary, not investment, legal or financial advice.