Running a small storage facility on a ledger, not a shoebox
A 20-to-60-unit storage facility sits in an awkward software gap: big operators run enterprise platforms with monthly fees that would eat a small facility's margin, while the small operator runs on a gate-code list, a stack of checks, and a memory of who's behind. The memory is the problem. Storage billing is brutally simple — the same amount, every month, per occupied unit — which means the whole business can run on arithmetic, if the records are shaped to compute.
Charges should accrue, not be invoiced
The elegant property of storage billing: what a tenant owes is a formula, not a stack of invoices. Months on the books × the unit's rate = charged to date. Log every payment against the unit, and charged minus paid is the tenant's balance — always current, no invoice ever written. Positive means behind. Negative means paid ahead, which is a credit and exactly what it looks like. One row per unit, one row per payment: that's the entire bookkeeping system for the revenue side. (Whole-month billing keeps the formula clean; if you prorate move-ins, adjust the first payment — the policy is yours.)
The three numbers that run the business
- Occupancy — units filled over units total, overall and by size. The by-size split is the marketing department: if the 10×10s are always full and the 5×5s always aren't, the waiting list and the next price change both have their answer.
- The delinquency list — who's behind, by how much, oldest first. What happens next (late fee, overlock, lien process) is governed by your state's self-storage lien statute and your rental agreement — the ledger's job is making sure you know before the statute's clock matters.
- The vacancy bleed — the rent your empty doors would earn each month, added up. Five vacant units at an average $91 is $455 a month, $5,460 a year: the number that justifies the crack-filling, the new sign, and the Saturday spent showing units.
| Size | Units | Occupied | Occupancy | Potential / mo |
|---|---|---|---|---|
| 5 × 5 | 6 | 4 | 67% | $270 |
| 5 × 10 | 6 | 5 | 83% | $420 |
| 10 × 10 | 6 | 5 | 83% | $660 |
| 10 × 15 | 3 | 3 | 100% — raise it? | $435 |
The fully-occupied row is as informative as the empty ones: a size that never has a vacancy is a size that's underpriced, and the ledger surfaces it without an opinion attached.
A rent roll that charges itself, honest balances, and the empty doors priced
The Self-Storage Unit Tracker is this ledger as a workbook: 60 unit slots where CHARGED accrues automatically from move-in, a 300-row payments log, balances red when a tenant owes, occupancy and the vacancy bleed live, a by-size table, and a dashboard naming the delinquent. Pure formulas, no macros, Excel & Google Sheets.
An hour of setup for a facility that reports itself
List the units with sizes and rates, add tenants and move-in dates, log the payments you can reconstruct, and run forward from there. To be clear about this note's boundary: it describes record keeping, not legal or tax advice. Late fees, overlocks, lien sales, and auction notice periods are governed by your state's self-storage lien statute and your own rental agreement — the ledger keeps the facts those processes require.