Calculate startup valuations and investor equity for fundraising rounds.
Pre-money valuation is the company's value before receiving new investment. Post-money valuation equals the pre-money plus the new capital raised. The investor's ownership percentage equals their investment divided by the post-money valuation.
A startup with a $10M pre-money valuation raises $2.5M. Post-money = $12.5M. The investor owns 2.5M/12.5M = 20%, and founders retain 80%.