Conquer the 2026 McKissock General Appraiser Exam – Master the Sales Comparison Approach!

Both GIM and GRM are quick, multiplier-style measures that rely on gross income figures to estimate value for income-producing properties. GIM uses annual gross income (often gross potential or effective gross income) to estimate value, while GRM uses gross rent, usually the monthly rent, to estimate value. Because they ignore operating expenses, they’re useful for fast comparisons when you want a rough sense of value based on revenue alone. In practice, these two are used together to get a quick sense of how properties compare: GIM provides a broader gross-income view, and GRM ties that concept specifically to rental streams. Other metrics like cap rate or IRR require expense data and detailed cash-flow assumptions, so they serve different purposes and aren’t used in the same simple, gross-based comparison.