Article: From Myth to Math: A Tutorial on the Actuarial Valuation of Charitable Remainder Unitrusts under I.R.C. § 7520

Charitable Remainder Unitrusts (CRUTs) are a mainstay of charitable planning, yet the derivation of the income tax charitable deduction is often treated as a black box. Practitioners routinely rely on IRS actuarial tables without a clear account of the computational steps that produce the published remainder factors. This Article explains the mathematics underlying I.R.C. § 7520 and Treas. Reg. § 1.664-4, translating the operative provisions into explicit formulas. The result is a replicable method for independently verifying remainder factors and constructing proprietary valuation models, illustrated through a companion CRUT calculator implementing the described approach.