Self-Storage Acquisition & Underwriting Financial Model — Unit-Mix + ECRI Revenue Engine

Gross potential rent is built bottom-up via SUMPRODUCT across six unit sizes, so net rentable square feet, total units and the headline rent per square foot all fall out of the same rent roll. It then runs the one bridge almost every template skips: physical occupancy to economic occupancy (physical minus a concession gap minus a delinquency gap), and books revenue on what you actually collect. Same-store growth comes from ECRI, the existing-customer rate increase net of induced vacate, the way the public REITs really raise rent. Then it underwrites the purchase as an acquisition: price from in-place NOI and the going-in cap, the capital stack, DSCR, the unlevered yield-on-cost, a Year-1 lease-up runway and a conservative 5-year exit.

• Unit-Mix Revenue Engine across six unit sizes (locker through climate-controlled).
• Physical-to-economic occupancy bridge, the most common way storage pro formas overstate income.
• ECRI growth with a source, not a flat invented percentage.
• 3-facility-class toggle: Class A (urban/climate), Class B (suburban), Class C (drive-up).
• Full acquisition underwrite: DSCR, unlevered yield, 5-year exit and equity multiple.

Honest by design: self-storage in 2024-25 runs negative leverage (caps below debt rates), so the headline is the unlevered yield, DSCR and the equity multiple, not a leverage-flattered cash-on-cash. Educational planning tool, not financial or investment advice. 10-sheet Excel workbook (Google Sheets compatible) plus an 18-page PDF guide.