SAFEs into Series A

This is the conversion that surprises people: SAFE percentages were promised before new money and before the new option pool. Series A sells a slice of a larger pie. The pool is usually carved from the pre-money parties — founders and converting SAFEs — not from the new investor's percentage.

Assume caps bind (Series A is not below the caps in a way that switches to round-only pricing). SAFE conversion first, from stacking:

Walking through pool + new money

Post-round fully diluted shares (including unissued pool) = T.

Series A ownership = 5 / 25 = 20% of T
Unissued pool      = 10% of T
Founders + SAFEs   = 70% of T

12,500,000 = 0.70 × T
T = 12,500,000 / 0.70 ≈ 17,857,143 shares

Series A shares = 0.20 × 17,857,143 ≈ 3,571,429
Option pool     = 0.10 × 17,857,143 ≈ 1,785,714
PPS             = $5,000,000 / 3,571,429 ≈ $1.40

Sanity check on pre-money:

Shares just before new money = 12,500,000 + 1,785,714 = 14,285,714
Pre-money value = 14,285,714 × $1.40 ≈ $20,000,000  ✓

The 1,785,714 pool shares were created so that after the round the unissued pool is 10%. That is the classic option pool shuffle: the pool is carved out of pre-money parties, not out of the new investor's 20%. Negotiating pool size and whether it is measured pre- or post-money is a real economic fight — see option pools and priced rounds.

Dilution narrative: Founders started at 100%. After SAFEs they were at 80%. After Series A and a 10% post-money pool they are at 56%. SAFE holders went from a promised 20% to 14%. Series A owns 20% by construction.

Common mistakes

• Forgetting the post-money pool. Series A % is not the only dilution at the round.
• Treating SAFE % as post-round %. The 20% became 14%.
• Letting the investor's 20% absorb the pool. Market default is the opposite.

Check yourself

After conversion, founders + SAFEs hold 12,500,000 shares. Series A wants 20% and the pool 10%. What is T?

12,500,000 / 0.70 ≈ 17,857,143.

Who paid for the 10% pool in this structure?

Founders and converting SAFE holders — the pre-money parties — not the Series A investor.

Key takeaways

• Model new money % and post-money pool % together; old holders share the remainder.
• In this example: founders 56%, SAFEs 14%, Series A 20%, pool 10%.
• The pool shuffle is a stealth valuation cut. Size it from a hiring plan.

Further learning

YC SAFE conversion calculatorFree SAFE conversion and dilution calculator from Y Combinator. Model valuation caps, discounts, MFN, stacked SAFEs, option pools, and Series A conversion.Y Combinator