Chicago zoning comparison · the mid-density apartment step
RM-4.5 vs RM-5: which lets you build more?
RM-5 carries the larger envelope — FAR 2 vs 1.7; on a standard 25 × 125 ft Chicago lot, RM-5 permits 7 units by right against 4.
Figures originally read from a Title 17 excerpt in a third-party zoning report dated 18 September 2024. On 24 August 2026 the bulk standards — floor area ratio, lot area per unit, building height and minimum lot area — were re-checked against the current adopted edition 2026-S-73 and found unchanged. Setbacks and parking ratios were not part of that pass and still rest on the 2024 reading. Data snapshot generated 2026-08-24. How this data is produced and checked →
Side by side
| RM-4.5 Residential Multi-Unit 4.5 | RM-5 Residential Multi-Unit 5 | |
|---|---|---|
| Max FAR | 1.7 | 2 |
| Max height | 47 ft | 47 ft |
| Lot area per unit | 700 sf | 400 sf |
| Units on a standard 25×125 ft lot | 4 | 7 |
| Min lot area | 1,650 sf | 1,650 sf |
| Residential parking / unit | 1 | 1 |
| Max lot coverage | 60% | 65% |
| Permitted uses | multi-unit residential and townhouses | multi-unit residential |
| Connected Communities bulk bonus tier | No | No |
Green marks the more permissive value. Setbacks are contextual in both districts and omitted here — see the district pages for the working scalars and the governing formulas.