Every round sells part of the company. Dilution is not bad by itself, since a smaller share of a more valuable company can be worth much more. But founders should know what each round costs and model the path ahead.
Typical dilution by stage
| Stage | Median dilution | Source |
|---|---|---|
| Seed | About 18% | Carta, US software (2026)1 |
| Series A | Typically around 20% | Carta (2025)2 |
| Series B | 12–13% | Carta, US software (2026)1 |
| Series C | About 9% | Carta, US software (2026)1 |
How it compounds
Dilution multiplies. If founders own 100% before seed and sell the median at each stage above, they keep roughly 82% after seed, about 66% after Series A, about 58% after Series B and about 52% after Series C, before any option pool. Illustrative; real outcomes vary widely.
What else dilutes
- The option pool, especially when it is expanded in the pre-money valuation. See our cap table guide.
- SAFEs and notes converting at the priced round. See our SAFE guide.
- Bridge rounds between priced rounds. See our bridge round guide.
What to have ready
- A pro forma cap table for the next round at several valuations and round sizes.
- The fully diluted share count, including every instrument that converts.