Dilution is the reduction in your ownership percentage when a company issues new shares. It sounds like something to fear, and founders often do, but a smaller slice of a much larger pie is the entire point of raising money. The danger is not dilution; it is dilution you did not see coming.
Every time a company raises a round, creates an option pool, or converts a SAFE, it issues new shares. The total pie grows, so each existing holder now owns a smaller percentage of it. If the new money makes the company worth enough more, the smaller percentage is worth more in dollars than the larger one was. That is healthy dilution.
Dilution turns painful in three ways: raising too much at too low a valuation, stacking SAFEs and notes whose combined conversion is larger than expected, and oversized option pools carved out pre-money. Each is avoidable with modeling. Unhealthy dilution is usually a planning failure, not an inevitability.
The defense is a live, fully diluted cap table and the discipline to model every round's dilution before signing, including all conversions and pool changes. Founders who track this hold their ownership deliberately; founders who do not wake up owning far less than they thought. This is general information, not investment advice.
Fear the surprise, not the dilution.