What Are Pro Rata Rights? Examples & Free Calculator (2026)

Your Series A is nearly done. Then your seed fund emails: "We'd like to take our pro rata." Most founders reply "of course" and move on. But that one line decides how much of the round your new lead can buy. Sometimes it also decides how much of the company you keep. Below we explain pro rata rights in plain English and work through one round three ways. You also get a free Excel calculator for your own numbers.

Pro rata rights let an existing investor buy into your next round to keep its percentage of the company. It's a right, not a duty. Say a seed fund owns 10% of your company. It can buy 10% of the new shares in your Series A and stay at 10%. Most companies give this right only to bigger investors, called major investors.

How do pro rata rights work?

When you raise a new round, the company first offers each major investor its share of the new shares. They pay the same price as everyone else. That share is the investor's current fully diluted percentage. It can take all of it, part of it or none. What it skips can go to other existing investors first, then to new ones.

Fully diluted means you count every share, option and pool share as if it already existed. Say your seed fund owns 10% on that basis. Your Series A will issue 2,000,000 new shares. The fund can buy 200,000 of them and stay at 10%. If it passes, it keeps its shares, but they're now a smaller slice of a bigger company.

Pro rata goes by other names too. Lawyers also say participation rights or pre-emptive rights. The NVCA model investors' rights agreement, the US template most deals start from, calls it a right of first offer. It's one of the control terms you'll see in a term sheet. Here's how the NVCA version works.

1. The offer notice — the company tells each major investor the price, the terms and how many shares it will sell.
2. 20 days to decide — each investor says how much of its share it wants, up to all of it.
3. A 10-day top-up — investors who took their full share can split whatever the others skipped. Lawyers call this over-allotment.
4. The rest goes out — the company can sell what's left to anyone within 90 to 120 days. It can't offer a lower price or better terms.

Say two major investors each own 10%. One takes its full share and the other passes. The first can then ask for the shares the second left behind. The NVCA notes call this top-up mainstream and rarely negotiated.

Not every new share triggers the right. The model leaves out option pool grants and IPO shares. It also offers optional carve-outs for acquisitions and for warrants given to lenders (NVCA certificate of incorporation).

The quick maths: an investor's pro rata check is its ownership times the round size. A seed fund with 15% of a $10M round can put in $1.5M. That works when the round size already includes the fund's own money. If pre-money and post-money still feel slippery, our post-money valuation guide walks through them.

Pro rata calculator and example (free Excel download)

Multiply the investor's fully diluted ownership by the number of new shares in the round. Then multiply by the price per share to get the check. Our free Excel calculator does this for every investor at once. It also shows how much room is left for your lead and what founders keep.

Here's what the calculator does, line by line, using the worked example below:

How do pro rata rights dilute founders?

Not by themselves. If the round size stays fixed, pro rata only moves shares from your new lead to an existing investor. Founders lose nothing extra. But if the lead still wants its full stake, the round has to grow. Then founders, and everyone without pro rata, give up more.

Here's one Series A, worked three ways, for a fictional software startup. The founders own 70% before the round. A seed fund owns 15% and is the only investor with pro rata. The new lead offers $8M at a $32M pre-money, and it wants 20% of the company.

Look at the middle column first. The round is the same size, so the founders end at 56% either way. The seed fund's $1.2M simply comes out of the lead's slice. Plenty of leads accept that. But many have a target stake and won't go below it. That's the right-hand column. The round grows to $9.85M, and the founders end at 53.5%. That's 2.5 points of your company for money you didn't plan to raise.

Who gets pro rata rights?

Usually only major investors: those who hold at least a set number of shares. Your lead and your biggest early backers clear the bar. Small angel checks usually don't. The bar is negotiated, so set it on purpose. Every investor with pro rata is one more claim on your next round.

Pro rata is close to standard for VC money. In one large survey, VCs said they include it in 81% of their deals (Gompers, Gornall, Kaplan and Strebulaev). What's not standard is giving it to everyone. The NVCA model gives it to major investors and leaves the threshold blank. Its notes explain why: giving it to everyone complicates later rounds.

Y Combinator makes the same point for SAFEs. Its FAQ says an investor buying a $500K SAFE has a better case for pro rata than one investing $10K (Y Combinator).

What counts as a major investor?

There's no legal definition. You and your lead pick the bar. There are four common ways to set it.

The bar matters more than it looks. Here's the same Series A when more investors hold pro rata. The lead still wants 20%.

YC's own guide shows a fix. In its example, a startup raises $1M. Three investors put in $250K each, and 25 angels put in $10K each. Only the three big ones get pro rata (YC SAFE User Guide). That also makes the next round faster to close, because fewer people need to sign off.

Raising in the UK?

In the UK, pre-emption is the default in law. Under section 561 of the Companies Act 2006, a company must offer new shares to its existing shareholders first. Each gets an offer in proportion to what it holds. It doesn't cover shares paid for other than in cash. And a private company can switch it off in its articles (section 567).

UK venture deals usually set their own rules in the articles, often starting from the BVCA model documents. Those limit pre-emption to investors or major investors, and let an investor majority waive it for a round (Shepherd and Wedderburn). That waiver is expected in most financings. The model articles also offer a clause that protects smaller investors if a waiving majority then invests itself (Farrer & Co).

Do SAFE investors get pro rata rights?

Not automatically. Y Combinator's post-money SAFE has no pro rata right inside it. You grant one with a separate side letter. YC's standard letter covers one round: the one where the SAFE converts, usually your Series A. The right ends when that round first closes.

This matters, because SAFEs now run the early market. In 2026, they're the default at pre-seed: 93% of pre-seed rounds on Carta in the second quarter were SAFEs (Carta). And 91% of all SAFEs on Carta that quarter were post-money. With YC's form, their holders have pro rata only if you signed a side letter.

Old pre-money SAFEs worked differently. Their built-in right applied to the round after the one where they converted, usually the Series B. YC says founders and investors often misread that (YC SAFE User Guide). It's one reason the right moved into a side letter.

YC also gives founders the maths for the extra dilution. Here's its own example:

YC's advice is to decide how much pro rata you can afford before you hand out side letters. Its guide works backwards. Say your SAFEs add up to 20% of the company. Your Series A investors want 25%, and you won't sell more than 28% in total, before the pool. Then only SAFEs worth about 10.7% can carry side letters, roughly half of them. For caps, discounts and conversion, see our SAFE note guide.

What is super pro rata, and should you agree to it?

Super pro rata is the right to buy more than your share of the next round. An investor that owns 8% might ask for a third of your Series A. It gives them a free option on your success. It also takes room from your next lead and can put that lead off. Avoid it if you can.

Mark Suster of Upfront Ventures made the case against it back in 2011, and it still holds (Both Sides of the Table). It often comes from a big fund writing a small early check. If you do well, that fund takes a large slice of your next round. A new lead may then find too little left to bother.

The second risk is the signal. Say the investor with super pro rata skips your next round. New investors will ask why, because it had the right and the inside view.

We see this from the investor side too, because 30% of our clients are funds. Some of the pitch books we build for VC funds promise their own investors exactly this: more money into the winners. One showed a 7.5% stake with the right to buy up to 10%.

If an early investor wants more, offer a head start instead of a guarantee. Promise them a first look at the next round, and let them earn a bigger share by helping. That's Suster's suggestion, and it's a good one. The standard top-up is fine, because it only covers shares others skip.

What happens if an investor doesn't use its pro rata?

Nothing dramatic. The investor keeps its shares, but its percentage falls as new shares are issued. Other major investors can take the shares it skipped. Whatever's left can go to new investors on the same terms. Some agreements also take the right away from an investor that doesn't use it in full.

That last rule is an optional use-it-or-lose-it clause in the NVCA model. It's worth asking for, because it stops a passive investor from holding a claim on every future round.

Passing isn't always a bad sign. Small seed funds often don't have the money, even for their best companies (Carta). Some fund the check through a separate vehicle instead. The NVCA model allows that: a major investor can share its right with its affiliated funds and its own investors.

Still, new investors notice. If a big, well-funded existing investor passes, expect your new lead to ask why. Have a short, honest answer ready.

How often do investors use pro rata rights?

Nobody publishes a clean exercise rate, but the data around it tells a clear story. VCs want the right badly. In one large survey, they rated pro rata as the term they're least willing to negotiate, ahead of liquidation preferences (NBER). Using it is another matter. Small funds often lack the cash to follow on. Carta's October 2026 report even floats new pro rata funds to fill that gap. Returns don't settle the question either. AngelList simulated thousands of seed portfolios. Never following on beat always following on in 54% of runs. But always following on had the higher average return. So when your seed fund passes, it may be a cash decision, not a verdict on your company.

How do founders negotiate pro rata rights?

Yes, but don't try to make the right disappear. VCs give it up less readily than any other term. In our work with 600+ startups since 2014, investors rarely drop it. They do accept limits on who gets it, how much and for how long. So spend your energy on the scope.

Where we'd push, in this order:

1. A real threshold — major investors only, by share count or check size. Set it once you know who's in the round.
2. No super pro rata — the standard right plus the top-up is enough. Offer a first look at the next round instead.
3. Use it or lose it — an investor that skips its full share loses the right for later rounds.
4. The standard carve-outs — option pool grants, IPO shares, acquisitions and lender warrants don't trigger it.
5. A majority waiver with a catch-up — a majority of investors can waive the right for one round. If one of them invests anyway, the rest get a fair chance to join.
6. Short SAFE side letters — only for big checks, and only for the round where the SAFE converts.
7. An early ask — about nine months before your next round, ask each investor whether they plan to take their pro rata. Our investor update template builds that question in.

Pro rata matters most when you raise again and again. Waveup prepared the investor materials for a European sovereign AI company's $5M seed and $15M Series A. We also built the lender materials for its $100M debt facility. It's now raising its Series B (see the case). In a run like that, every equity round brings the pro rata question back. Debt usually doesn't, because a plain loan isn't a new share. Our guide to venture capital vs venture debt compares the two.

We plan these allocations, model the dilution and negotiate pro rata on the founder's side. It's part of a fundraising engagement, alongside your lawyer. Your lawyer still drafts and signs off the documents. A good cap table tool helps you track who holds pro rata, and on what terms.