Average Series B Funding Amount in 2025: What the Data Shows by Sector

The average Series B funding amount in 2025 is $28M — but that single number will get you killed in a fundraise if you anchor to it wrong.

The range runs from $15M in commoditized vertical SaaS to $75M+ for AI-native infrastructure companies with triple-digit ARR growth. Where you land depends on sector, retention, growth rate, and whether your story fits the current market narrative. I have watched founders come in asking for $30M Series B when the data for their sector says $20M is the ceiling — and wonder why the process stalled.

Here is what the data actually shows for 2025, broken down by sector and what it means for how you should position your raise.

Average Series B Funding Amount in 2025: Data by Sector

Series B data varies significantly by vertical. Below are the median round sizes, post-money valuations, and ARR multiples by sector based on PitchBook, Carta, and NFX data through Q1 2026.

Sources: PitchBook Q1 2026, Carta State of Private Markets, NFX Financing Benchmarks. Ranges reflect 25th–75th percentile.

What Series B Investors Actually Require in 2025

The bar to raise a Series B has risen materially since the 2021 peak. Back then, you could raise a $30M B on $2M ARR with a good story and a hot sector. Today, that story needs to be backed by numbers that de-risk the next leg of growth. I have seen strong companies with $4M ARR struggle because they could not show a repeatable GTM motion — and that is the unlock investors are underwriting.

The typical Series B investor in 2025 is looking for: $3–10M ARR (sector-dependent), net revenue retention above 110%, year-over-year growth above 80%, a go-to-market motion that has worked at least two or three quarters in a row, and a clear path to $50M ARR within 24–30 months. Below those thresholds, you are either doing a bridge or negotiating hard for terms that reflect the risk.

The exception is AI infrastructure. Foundation model tooling, GPU orchestration, and agentic workflow infrastructure companies are still raising pre-revenue or near-revenue rounds at enormous valuations. That is a narrow band — do not mistake the exception for the rule. For everything else, the metrics bar is real.

How Series B Valuations Are Calculated

Series B valuations in 2025 are set almost entirely on forward ARR multiples — specifically, your projected ARR twelve months out multiplied by a comparable public SaaS or AI company multiple, then discounted for stage risk and illiquidity. The practical shorthand: take your NTM ARR estimate, apply a 12–18x multiple for SaaS or 20–35x for AI-native, and that is your pre-money valuation range before negotiation.

Public SaaS multiples as of Q1 2026 sit around 7–9x NTM revenue for the median public software company, per our SaaS Valuations dashboard. Private companies at Series B get a growth premium — typically 1.5–2x the public comparable — because they are growing faster than anything public. That premium compresses quickly if growth slows.

Net revenue retention is the single biggest lever on the multiple. Companies with 130%+ NRR can command the top of the range. Companies at 90% NRR are fighting uphill. I have seen two identical-ARR companies get $80M apart in Series B valuation because one had 140% NRR and the other had 95%. Retention is not a nice-to-have — it is the math.

5 Factors That Move Your Series B Valuation

• •Net Revenue Retention above 120% — the single highest-correlation metric to a premium valuation at Series B. Every point below 110% costs you multiple turns on the ARR multiple.
• •Growth rate trajectory — investors look at trailing 3-quarter CAGRs, not point-in-time snapshots. Deceleration from 150% to 80% growth tells a different story than consistent 90% growth.
• •Gross margin — 70%+ is table stakes for SaaS; sub-60% puts you in a different multiple bucket. AI companies burning compute costs often show 50–65% margins which require a different framing.
• •Capital efficiency — Series B investors are comparing your ARR-per-dollar-raised to cohort medians. Companies that reached $5M ARR on $8M raised are dramatically more interesting than those who needed $20M to get there.
• •Pipeline quality and GTM repeatability — the question every Series B lead is asking: can this company 3x revenue in 24 months with the capital from this round? If the GTM machine is not clearly working, the answer is no.

Series B Dilution: What Founders Give Up

The typical Series B investor takes 15–22% of the company. When you stack that on top of pre-seed (5–10%), seed (10–20%), and Series A (15–25%) dilution, the math gets uncomfortable fast. Most founders who have raised three rounds own somewhere between 30–50% of their company before any option pool refreshes or SAFE conversions.

The option pool shuffle is real at Series B. Most term sheets will require expanding the employee option pool to 10–15% on a post-money basis, and that dilution is typically carved out of the pre-money cap table — meaning it dilutes founders, not new investors. A $130M post-money B with a 12% option pool expansion effectively means founders give up more than the headline dilution number suggests.

The best protection against excessive dilution at Series B is a competitive process. A single-term-sheet situation gives investors pricing power. Two or more term sheets creates real negotiating leverage — on valuation, option pool size, pro-rata rights, and governance. Running a tight, time-boxed process with genuine competitive tension is not optional; it is how you protect your cap table.

The Funding-2025 Context: Why Series B Is Harder Than It Looks

According to PitchBook data, the number of Series B rounds completed in 2024 was down approximately 35% from the 2021 peak. Capital is concentrating in the top quartile of deals — the companies with the best metrics get multiple term sheets quickly; everyone else waits. The Series A to Series B conversion rate is roughly 30–40% industry-wide, meaning most companies that raise a Series A never make it to a Series B.

The implication: if you are planning a Series B raise in 2025 or 2026, start building LP relationships with growth equity firms 12–18 months before you need capital. The firms writing $25–50M checks at Series B have seen hundreds of companies. The ones they move fast on are the ones they have tracked for a year, seen execute consistently, and already trust. Cold inbound at Series B is a much harder path than most founders expect. You can track how funding rounds are evolving in real time on the Benchmarking Dashboard.