What there is a transfer of a residence or other real estate with a retained life estate (which is usually not recommended, because it does not avoid any inheritance tax and can restrict the ability of the transferor to sell the property during his or her lifetime), the retained life estate is not subject to tax but the remainder interest may be taxable if the transfer is not to a spouse, child, or other family member to whom transfers are exempt. See Example 3 of 61 Pa. Code § 91.165 and 61 Pa.Code § 91.193(b)(6).
When the remainder is taxable, the taxable value is usually determined by multiplying the value of the entire property by an actuarial factor, based on a current interest rate and the age of the life tenant. The most recent table of life estate and remainder factors was published as 49 Pa.B. 3023 (6/8/2019), effective July 1, 2019.