Cap Table Math for First-Time Founders: How a Pre-Seed SAFE Actually Dilutes You
The arithmetic nobody shows you before your first raise, worked out round by round.

A pre-seed SAFE dilutes you by the cash raised divided by the post-money cap. Raise $500K on a $5M post-money cap and investors own 10 percent. An option pool and a priced seed then dilute you further, so founders commonly hold 60 to 70 percent after seed.
A pre-seed SAFE dilutes you by the cash raised divided by the post-money cap. Raise $500K on a $5M post-money cap and investors own 10 percent. An option pool and a priced seed then dilute you further, so founders commonly hold 60 to 70 percent after seed. Here is the math, round by round.
Why founders get blindsided by dilution
The reason dilution feels like a surprise is that a SAFE does not show up on your cap table as equity until it converts. You sign it, the money lands, and your ownership on paper still reads 100 percent. The dilution is real but invisible until your priced seed round, when every SAFE converts at once and the founder ownership number drops in a single step.
The fix is to do the math up front, before you sign anything. The arithmetic is simpler than it looks, especially with the post-money SAFE that most US pre-seed rounds now use. You can see why the SAFE wins on speed and cost in this breakdown of SAFEs, convertible notes, and priced rounds at pre-seed.
The one formula you need
For a post-money SAFE, investor ownership is dead simple:
Investor ownership = amount raised divided by the post-money cap.
Raise $500K on a $5M post-money cap and investors own exactly 10 percent. That is the whole point of the post-money SAFE: the investor locks their percentage, and you carry the dilution from any further SAFEs you raise before the priced round. It is less founder-friendly on dilution than the old pre-money SAFE, but you always know exactly where you stand.
Working it through, round by round
Start with two founders holding 10,000,000 shares between them, 100 percent of the company. Watch what each event does. These numbers are illustrative, rounded to keep the logic clear.
| Event | New money | Post-money cap or valuation | New stake created | Founder ownership after |
|---|---|---|---|---|
| Starting point | - | - | - | 100% |
| Pre-seed SAFE | $500K | $5M post-money cap | 10% | 90% |
| Option pool top-up | - | - | 10% | ~80% |
| Priced seed round | $2M | $10M post-money | 20% | ~64% |
Two things to notice. First, the option pool comes out of the existing shareholders, which in practice means it comes out of you, not the new investors, because investors usually require the pool to be in place before their money goes in. Second, the SAFE and the pool both convert into the cap table at the priced seed, which is why founder ownership steps down sharply at that round rather than gradually.
The mistakes that cost the most equity
Three errors do the most damage at pre-seed.
Raising on too low a cap. A friendly early angle on valuation feels generous in the moment, but a low post-money cap means a bigger slice handed over for the same dollars. Tie your cap to a defensible milestone story, not to whatever closes the round fastest.
Stacking SAFEs without modeling them together. Each SAFE looks small alone. Three SAFEs at different caps stack into more dilution than founders expect, and with post-money SAFEs you absorb all of it before the priced round. Model the combined effect, not each note in isolation.
Sizing the round by feel. The amount you raise drives the dilution directly, so raising more than you need to hit the next milestone is just selling cheap equity. Size the round to the milestone, which is the logic in how much to raise at pre-seed.
Run your own numbers before you sign
Build the table above in a spreadsheet with your real caps and round sizes before you take any term sheet. The point is not to fear dilution, which is the cost of fuel, but to spend it deliberately. If you want the full sequence of decisions a raise runs through, the step-by-step pre-seed fundraising process lays them out in order, and the complete playbook lives in The Funding Framework.
Frequently asked questions
How much do founders typically own after a pre-seed and seed round?
Does a post-money SAFE dilute me more than a pre-money SAFE?
When does a SAFE actually hit my cap table?
Should I raise on a SAFE or a priced round at pre-seed?
Run your raise with a system, not a guess.
This is the kind of thinking The Funding Framework walks through, step by step, from story to close.