Your company's valuation immediately after the new investor money lands, equal to pre-money plus the amount raised in the round.
Notion raised $50M led by Index Ventures and Sequoia at a $2B post-money valuation in April 2020, despite having no formal sales team and a tiny headcount. The post-money number triggered a wave of 'why are Index and Sequoia paying that for a notes app' coverage, and was vindicated three years later when Notion's secondary round priced near $10B.
