A Post-Money Valuation is the value of a company assigned by its investors immediately after an investment. The Post-Money Valuation is equal to the pre-money valuation plus the amount of the investment. The Post-Money Valuation can be used to calculate the ownership of a new investor; if the Post-Money Valuation of a company after a financing is $20M and an investor had invested $4M into the financing, the investor purchased 20% of the company.