Cap tables are deceptively simple at the start. Two founders, a 50/50 split, ten million shares. Then friends and family put in $25K. Then an advisor takes half a point. Then a SAFE closes. Then another. Then the seed round prices.
By the time a founder sits down with a Series A partner and pulls up the cap table, they often discover that the company they thought they owned 80% of, they actually own 51% of. Sometimes less.
None of that compounding was inevitable. It happened because of decisions made one at a time, without modeling the next two rounds out.
The five decisions that compound.
1. SAFE caps.
A $500K SAFE at a $5M cap is not a $500K decision. It is a "what percent of the company will this convert into" decision. At a $5M cap, $500K converts to roughly 10%. Founders often anchor on "we raised $500K" without modeling that the conversion at the next priced round will produce 10% dilution at minimum, more if the round prices below the cap.
2. The order of SAFEs.
SAFEs convert based on the lower of cap or discount versus the priced round. If a founder runs two SAFEs at different caps ($4M and $6M), the lower cap converts at a better price for the investor and worse for the founder. Running multiple SAFEs at different caps inside a single financing window almost always disadvantages the founder.
3. Option pool sizing and timing.
Investors push to expand the option pool before the round so the dilution comes from the founders, not from the new money. A 10% pre-money option pool is the standard. A 15% one is not unusual. Modeling the pool expansion into the round economics before term sheets is the difference between losing 2% and losing 5%.
4. Advisor and broker equity.
Advisors at 0.25% to 0.50% are standard. A "fundraising advisor" offering 5% is not an advisor, they are a broker, and most institutional investors will not fund a company that has a broker on the cap table. Decisions about who gets equity have downstream gating effects on which investors will take the meeting.
5. Friends and family round structure.
Friends and family who write checks on common stock at a $10M valuation create a price floor problem. If the company later prices a seed at $8M, F&F holders are mathematically underwater. Use a SAFE or convertible note instead. Always.
The Series A math founders should run before the seed.
Before closing a seed round, run the Series A math out loud. Pick a plausible Series A: $10M raise at $40M pre. Now add the option pool expansion the Series A investor will require. Now layer in the seed pro rata rights. Now check founder ownership at the bottom.
If the founders are below 50% combined ownership after a hypothetical Series A, the seed round is too expensive. Negotiate harder, raise less, or restructure the option pool. Founders below 50% post-Series A have lower control, weaker recruiting leverage, and a harder Series B.
The same company, two cap tables.
Here is the math, using 2025 market medians from Carta and PitchBook so the numbers are real.
Two founders hold 10,000,000 shares between them. Pre-seed, they raise $800K: a $500K post-money SAFE at a $5M cap, then $300K at a $7.5M cap. Post-money SAFEs lock ownership at the cap, so that is 10% plus 4%, or 14% of the company spoken for before any priced round.
The seed is $4M at a $16M pre-money, the Carta median. The lead asks for a 10% option pool, post-money, carved out of the pre-money. New investors take 20%. The pool takes 10%. Everyone who was there before shares the remaining 70%. The founders go from 86% to 60.2%.
The Series A is $10M at a $40M pre-money, the PitchBook Q3 2025 median for a non-AI company. The new lead wants the pool at 12% post-money and takes 20%. The founders land at 45.5%, combined. Below half, two rounds in, with a Series B still to come.
Now run it again with two changes. The same $800K raised on one SAFE at a $10M cap, which is the Carta median for pre-seed rounds between $250K and $1M, locks 8% instead of 14%. And the seed pool negotiated to 8% on the back of a real hiring plan instead of a round number. The founders exit the seed at 66.2% and the Series A at 50.4%.
Five points of ownership at a $50M post-money is $2.5M, and the gap widens with every round after. Neither change required a better company. Both required the math to be run before the documents were signed.
Pro rata, in numbers.
Seed investors ask for pro rata rights: the right to buy enough of the next round to keep their percentage. A seed fund holding 20% exercises pro rata in a $10M Series A by writing a $2M check inside that round. That is $2M the new lead does not get to deploy, which is why leads sometimes push back on pro rata, and why founders should know before the A who holds it and whether they intend to use it.
What investors are running on you.
Before the partner meeting, the analyst has already modeled your cap table at the next two rounds. They know what your dilution looks like, whether the founder team will still have control after Series B, and whether the math works for a fund that needs a 3x outcome at exit.
If the math does not work for them, the meeting does not happen. This is rarely communicated as "your cap table is bad." It comes back as "the fit is not quite right." The fit was the cap table.
Tools versus operators.
There are good cap table tools. Carta, Pulley, AngelList stack. They model conversions, they manage securities, they handle the legal artifacts. What they do not do is tell you whether the next round will leave you with enough ownership to run the company.
That is a CFO question, not a tools question. The tool runs the math you tell it to run. The CFO knows which math to run.
Three things to do this week.
- Pull up your cap table. Model conversion of every SAFE at three different priced round outcomes ($4M, $6M, $10M pre).
- Layer in a 10% option pool expansion at the seed.
- Check founder ownership at the bottom of the cap table. If it is below 65% post-seed, you have a structural problem to fix before the round.
This exercise takes two hours. It is the highest-leverage two hours most pre-seed founders never spend.
The SAFE Modeler converts every SAFE at a priced round and shows founder ownership at the bottom. The valuation benchmarks have the 2025 to 2026 cap ranges by stage and sector, so you know where your cap sits before you negotiate it. For the instrument decision itself, read SAFE vs. priced round.