Equity Dilution Calculator

New capital raises dilute existing ownership. Pro-rata participation maintains your share; skipping it shrinks your ownership. This calculator computes post-raise ownership given pre-money valuation, new raise size, and your level of participation.

Original ownership %

Original equity invested

New raise amount

Pre-money valuation for new raise

Your participation in new raise

Post-dilution ownership %

25.00%

Ownership lost to dilution

0.00%

Your new capital contribution

$125,000

Post-money valuation

$5,500,000

New investor share of company

9.09%

How the math works

Equity dilution happens when new shares are issued — your old % shrinks unless you participate pro-rata. Anti-dilution rights (common in venture, rare in real estate) protect existing holders from dilution below a certain threshold. Participation in new rounds keeps your ownership intact.

Pro-rata participation = maintaining your share of each new round. If you own 25% pre-raise and the raise is $500K, pro-rata participation = $125K. Skipping pro-rata dilutes you; funding it maintains ownership.

How to Use

Enter your current ownership % and original equity invested.
Enter new raise amount and pre-money valuation.
Enter your participation % in the new raise.
Read post-dilution ownership.

Frequently Asked Questions

Pre-money vs post-money?

Pre-money = valuation before new money comes in. Post-money = pre-money + new raise. Ownership is always computed on post-money. A $5M pre-money with $500K raise = $5.5M post-money; new investors own 500/5500 = 9.1%.

Can I block dilutive rounds?

Only if you have veto rights in the operating agreement. Most common in minority protection: thresholds (e.g., 2/3 approval for new equity). Real estate partnerships rarely grant formal veto.

Anti-dilution protection?

Rare in real estate, common in venture. Full-ratchet adjusts existing equity down to new-round price. Weighted-average (Broad-based vs Narrow) is a less punitive version. Worth asking about on larger JVs.