Gross Potential Income
The Top-Line Income Starting Point for Underwriting
Gross Potential Income (GPI) is the maximum rental income a property could generate if every unit were rented at market rent for the full period, with no vacancy, no concessions, and no unpaid rent. Think of GPI as the “top-line ceiling” for rental income—it’s your starting point before you apply real-world loss factors.
Why GPI matters
GPI is used to:
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Set a baseline for underwriting and cash flow projections
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Compare properties consistently (apples-to-apples)
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Estimate upside when rents are below market
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Support valuation analysis (because income drives value)
How to Calculate GPI
GPI (Monthly) = Total Number of Units × Average Market Rent per Unit
GPI (Annual) = Monthly GPI × 12
Example (same-unit property):
A four-unit building where each unit could rent for $1,000/month at market:
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Monthly GPI = 4 × $1,000 = $4,000
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Annual GPI = $4,000 × 12 = $48,000
Many properties have different unit types (e.g., 1-bed vs. 2-bed). In that case, calculate GPI by unit type:
GPI (Monthly) = Σ (Units of Type i × Market Rent of Type i)
Example (unit mix):
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2 × 1-bed @ $1,300 = $2,600
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2 × 2-bed @ $1,700 = $3,400
Monthly GPI = $2,600 + $3,400 = $6,000
Annual GPI = $6,000 × 12 = $72,000
Market rent vs. current rent
GPI is typically based on market rent (what the units should rent for today), not necessarily what tenants are currently paying. If a property’s current rents are below market, GPI helps you quantify the revenue potential—but you still need a realistic plan and timeline to reach it.