The performance of a particular scheme of a mutual fund is denoted by its NAV. In simple words, NAV is the market value of the securities held by the scheme. Since the market value of securities changes every day, NAV of a scheme also varies on day to day basis. The NAV per unit is the market value of securities of a scheme divided by the total number of units of the scheme on any particular date.
For example, if the market value of securities of a mutual fund scheme is INR 200 lakh and the mutual fund has issued 10 lakh units of INR 10 each to the investors, then the NAV per unit of the fund is INR 20 (i.e.200 lakh/10 lakh). NAV is required to be disclosed by the mutual funds on a daily basis.