Bridge Round Explained: Inside vs. Outside, Terms, Sizing

A bridge round is short-term financing that carries a startup to its next priced round, a sale, or profitability. Existing investors usually fund it through a convertible note or SAFE, sized to reach one milestone plus the next raise. For investors, the key question in our view is whether the money improves the company's position or only delays a hard conversation.

Definition: A bridge round is interim capital, most often a convertible note or SAFE from insiders, that carries a company from one funding event to the next when it cannot or does not want to price a full round yet.

Every bridge has a far bank. The whole job is checking that it's there.

What a bridge round is and why companies raise one

Cooley GO defines a bridge financing as one intended to give a startup the capital it needs to get to a subsequent funding round or sale transaction. In our view, three situations account for most bridges:

1. The milestone bridge. The company is close to a metric that would justify a much higher valuation and needs a few months to get there.
2. The market bridge. The company is performing but the fundraising market is slow, and insiders would rather extend runway than accept a flat or down round.
3. The rescue bridge. The company has missed its plan, cannot raise from outsiders, and insiders are deciding whether to fund a turnaround or let it wind down. Founders who run the default alive or default dead test monthly often see this coming in time to cut burn.

The first two are fairly ordinary. The third is where we think investors tend to lose the most money. The optimism that justified the original check makes it easy to keep writing new ones.

Inside vs. outside bridge rounds

Bridges tend to start as inside rounds, funded by the investors already on the cap table, and bring in new money only if insiders cannot fill the round. The two versions tend to behave differently:

In our view, an outside investor is the clearest market test of price. When insiders bridge alone, they are setting the price of their own position. That's worth extra scrutiny from every party, including founders and the insiders who sit out.

"A bridge round means the company is in trouble"

That's the reflex, and sometimes it's right. Rescue bridges exist, and they are rarely pretty.

But the data suggests bridges are a normal part of the cycle now. Carta's most recent dedicated bridge analysis, published in September 2025, found that 16.6 percent of all venture cash raised on its platform in Q2 2025 came through bridge rounds, up from 11.8 percent in Q2 2024. During the 2021 bull market, bridges typically made up less than 10 percent of cash raised in any given quarter. At Series A, bridges made up 22.5 percent of cash raised in Q2 2025.

One likely reason is time. Carta measured a median gap of 696 days (about 23 months) between primary rounds in Q2 2025, up from nearly 600 days two years earlier. Companies that planned for 18 months of runway appear to be bridging the difference. A bridge isn't a verdict. It's a question about what the money buys.

Priced rounds have improved since then. Carta's Q1 2026 report puts the down-round rate at 11.4 percent, and Cooley's Q2 2026 Venture Financing Report shows 83.6 percent of the deals it reported were up rounds and 12.1 percent were down. A bridge that gets a company to an up round is usually a good trade; one that does not often ends in a down round or a recapitalization.

How a bridge round is structured

Most bridges use one of two instruments:

• Convertible note. Debt that converts into the next round's preferred stock. Cooley GO's convertible debt primer says interest rates around 4 percent have become more common (6 to 10 percent used to be typical), discounts typically run 15 to 25 percent, and the qualified financing that forces conversion is often one to two times the note principal. J.P. Morgan notes that maturities typically run 12 to 24 months.
• SAFE. Y Combinator's post-money SAFE carries no interest and no maturity date. YC's user guide describes three standard versions (valuation cap only, discount only, and uncapped MFN) plus an optional pro rata side letter.

Cap, discount, MFN and qualified financing each have an entry in the venture capital terms glossary. Five terms tend to decide who comes out ahead in a bridge:

1. Valuation cap. Often at or near the last round's post-money for a milestone or market bridge, and well below it for a rescue bridge.
2. Discount. Vela Wood calls a 20 percent discount standard. When a note has both, the investor converts at whichever price is lower.
3. Maturity and interest (notes only). These can give noteholders leverage if no round closes.
4. Change of control. Vela Wood notes that convertible notes often repay 1.5x or 2x principal if the company sells first. The post-money SAFE pays the greater of the purchase amount or the as-converted amount at the cap.
5. Pro rata and information rights. Bridge investors usually want to preserve their right to invest in the next round.

Illustrative worked example (conversion): A seed company raised $3M at a $15M post-money valuation. Its two largest investors put in a $1M bridge note with a $15M cap and a 20 percent discount. Eight months later it closes a Series A at $30M pre-money. Assume 10 million fully diluted shares before the round and ignore accrued interest:

• Series A price: $30M / 10M = $3.00 per share, so $1M buys 333,333 shares.
• Discount price: 80 percent of $3.00 = $2.40, which would give 416,666 shares.
• Cap price: $15M / 10M = $1.50, which gives 666,666 shares.

The cap gives the lowest price, so it controls, and the bridge investors get twice the shares that $1M buys at the Series A price. That's the reward for taking the risk early. The investor guide to the convertible note works through the formulas in more detail.

How to size a bridge round

We'd size the bridge from the milestone backward, not from what insiders feel comfortable writing. It's the same logic we apply to how much money to raise in any round. One simple four-step approach:

1. Name the milestone and the months needed to hit it.
2. Add time for the next raise. A common rule of thumb is to start raising with 9 to 12 months of runway left.
3. Multiply by net burn after any planned cuts or hires.
4. Subtract cash on hand. The remainder is the bridge.

Illustrative worked example (sizing): The same company burns $100K a month and has $400K left, or 4 months of runway. It needs 5 months to hit its Series A metric and wants 9 months of runway left when the process starts. That is 14 months times $100K, or $1.4M, minus $400K on hand: a $1.0M bridge that adds 10 months of runway. The founder-side guide to startup burn rate and runway covers the burn side of this math.

The classic mistake is a bridge so small that it forces another bridge three months later. Stacked notes and SAFEs with different caps also convert together, so it helps to keep a live cap table with every instrument's terms.

The investor's decision: bridge or no bridge

The Cooley GO glossary warns that funding which does not materially improve a company's valuation or financing prospects can become a "bridge to nowhere." Four questions we'd ask before committing:

What does this money buy? Ask for a bottom-up budget showing which metric the bridge moves. "Six more months" is a weak answer. "Six months to get from $40K to $100K MRR with two sales hires already in the pipeline" is a much stronger one.

Who else is participating? If the last round's lead declines to bridge, that tells you something. A bridge where every insider funds pro rata tends to signal shared conviction.

What is the downside case? Model the outcome if no priced round follows: a lower-priced round with anti-dilution adjustments, a sale below the preference stack, or a shutdown.

Is the price honest? Insiders bridging at the last round's cap when the company has lost ground are, in effect, marking their own book. Some funds ask for a lower cap or larger discount in rescue bridges, or attach a pay-to-play provision so investors who decline lose preferred rights. Cooley's Q2 2026 report found pay-to-play provisions in 8.4 percent of the deals it reported.

Where we land on bridge rounds

We'd back a bridge that buys a specific, measurable milestone at an honest price. We'd be wary of one that buys time and nothing else. If nobody can say what the money buys, that tells you most of what you need.

Your situation may differ. An insider with a small position and a strong belief in the team can reasonably fund a long-shot bridge that a larger fund would pass on.

New angels often face their first bridge decision as an insider, when a portfolio company runs low on cash. 1752vc's Emerging Angels program puts accredited investors inside a working fund's process for eight weeks, with live diligence calls and monthly Investment Circles where questions like "do we bridge this one" get argued with real numbers. The founder-side startup fundraising guide covers the same decision from the company's chair.

The bottom line

A good bridge ends somewhere you can name. A bad one ends at the next bridge.

Time is what the bridge buys.

Progress is what it needs to buy.

Key takeaways

• A bridge round is interim capital, usually a convertible note or SAFE from existing investors, that carries a company to its next priced round or exit.
• Inside bridges are fast but let insiders set their own price; in our view an outside investor is the clearest market test of the terms.
• Carta found bridges made up 16.6 percent of venture cash raised in Q2 2025, as the median gap between primary rounds stretched to about 23 months.
• One way to size a bridge is from the milestone backward: months to the milestone plus 9 to 12 months for the next raise, times net burn, minus cash on hand.
• The valuation cap, discount, maturity, change-of-control terms, and pro rata rights largely decide what a bridge investor earns on conversion.

Frequently asked questions

What is a bridge round in startups?

A bridge round is a short-term financing that funds a startup until its next major funding round, acquisition, or profitability. It is typically structured as a convertible note or SAFE and funded mostly by existing investors. In our view the goal is to reach a milestone that supports a better price, not simply to buy more time.

What is the difference between an inside and an outside bridge round?

An inside bridge is funded by investors already on the cap table, so it closes quickly with light diligence, but insiders effectively set the price of their own position. An outside bridge brings in new investors, takes longer, and usually comes with a lower cap or tougher terms. Outside participation is usually a stronger signal that the market believes in the company's progress.

How big is a typical bridge round?

Bridge size depends on burn rate and the milestone, not on stage, so it varies widely. One way to work it out is months to the milestone plus 9 to 12 months for the next raise, multiplied by net burn, minus cash on hand. For a seed-stage company that often lands between several hundred thousand dollars and a few million.

Is a bridge round a bad sign?

Not necessarily. Carta's data shows bridges grew to 16.6 percent of venture cash raised in Q2 2025 as the time between rounds stretched to nearly two years, so many healthy companies use them. The warning signs we would watch for are terms that ignore the company's actual progress and a bridge that only some insiders are willing to fund.

Do bridge rounds use convertible notes or SAFEs?

Both are common. Notes carry interest and a maturity date, which gives investors more leverage if no round closes, while YC's post-money SAFE has neither and is simpler to document. Both usually convert at a discount to the next round's price or at a valuation cap, and investors get whichever price is lower.

Sources

• Cooley GO: Definition of Bridge Financing
• Cooley GO: Primer on Convertible Debt
• Y Combinator: Post-Money SAFE User Guide
• Carta: Bridge Rounds Got a Boost in Q2
• Carta: State of Private Markets, Q1 2026
• Cooley: Q2 2026 Venture Financing Report
• Vela Wood: The Basics of Convertible Notes
• J.P. Morgan: How Convertible Notes Work for Startups and Founders