How to Read a Hawaii Zoning Code (R-5, A-2, BMX-3, AG-1, P-2…)
Honolulu County's zoning ordinance reads like alphabet soup until you know the pattern. Then it's three categories with one number that tells you almost everything you need to know about what you can build.
The pattern
Every zoning code in Honolulu County follows roughly the same shape: one or two letters identifying the use category, optionally a hyphen, optionally a number identifying the intensity within that category.
R - 5
│ │
│ └─ Number: smaller = more dense, larger = less dense
│ (for residential: minimum lot size in thousands of sqft)
│ So R-5 means 5,000 sqft minimum lot, R-10 means 10,000.
│
└──── Letter prefix: use category
R = Residential A = Apartment
B = Business BMX = Business Mixed-Use
I = Industrial IMX = Industrial Mixed-Use
AG = Agricultural P = Preservation
F = Federal/Military C = Country
A-1, A-2, A-3 = apartment density tiers (low/med/high)
Residential codes (R-3.5, R-5, R-7.5, R-10, R-20)
The most common Oahu zoning. The number is the minimum lot size in thousands of square feet — your parcel must be at least that large to legally exist as a single lot.
| Code | Min lot | What it means |
|---|---|---|
| R-3.5 | 3,500 sqft | Densest single-family — most of older Honolulu (Kalihi, Kapahulu, Kaimuki). |
| R-5 | 5,000 sqft | Standard urban single-family. Most of east Oahu suburbs (Hawaii Kai, Aina Haina, Kahala flats). |
| R-7.5 | 7,500 sqft | Larger lots — Kailua, Lanikai, Mililani, parts of Manoa. |
| R-10 | 10,000 sqft | Estate-scale lots — Hawaii Loa Ridge, Diamond Head fringe, parts of Niu Valley. |
| R-20 | 20,000 sqft | Large estate. Rare. Some Tantalus, Aina Haina top, Diamond Head Crater rim. |
On a typical R-5 lot you can build one principal dwelling plus an ADU (Ohana unit, where allowed). Setbacks, height limits, and floor-area ratios constrain what fits — those vary by zone and by special-purpose overlays the lot may sit under.
Apartment codes (A-1, A-2, A-3)
Apartment zoning doesn't use lot size. The number tracks the intensity / max FAR (floor-area ratio).
| Code | Density | Where |
|---|---|---|
| A-1 | Low — 0.9 FAR, 40 ft height | 2-3 story walk-ups in older neighborhoods (parts of Makiki, Kalihi). |
| A-2 | Medium — 1.9 FAR, 60 ft height | 4-6 story buildings — most of older Waikiki rear streets, parts of Punchbowl. |
| A-3 | High — 3.5 FAR, 350 ft (with bonuses) | Honolulu high-rises — Kakaako, the Waikiki strip, downtown periphery. |
Business + mixed-use (B-1/B-2, BMX-3/BMX-4)
Pure commercial (B-1, B-2) is increasingly rare in modern Honolulu — most high-traffic corridors are now BMX (Business Mixed-Use), which requires both commercial use on the ground floor and residential above.
| Code | Use |
|---|---|
| B-1 | Neighborhood retail (corner stores, small offices). Disappearing. |
| B-2 | Community business — bigger retail, restaurants. Mostly along older highways. |
| BMX-3 | Community mixed-use. Ground-floor retail + 4-6 story residential. Parts of Kakaako, Kapiolani Blvd. |
| BMX-4 | Central mixed-use — high-rise scale. Most of the new Kakaako towers, downtown. |
Agricultural (AG-1, AG-2)
| Code | Min lot | What it allows |
|---|---|---|
| AG-1 | 5 acres | Restricted ag — large parcels intended to stay in active production. |
| AG-2 | 2 acres | General ag — looser, allows farm dwellings, orchards, small-scale ag-tourism. |
Important: a "farm dwelling" on AG land has restrictions on who can occupy it (must be involved in the agricultural operation), and short- term vacation rentals are explicitly prohibited on most ag-zoned land. Buyers chasing "ag for the lot size" without the farming intent get burned regularly.
Preservation (P-1, P-2)
| Code | Use |
|---|---|
| P-1 | General preservation — open space, watersheds, conservation lands. |
| P-2 | Restricted preservation — cultural / scenic / military buffer (Diamond Head crater, Punchbowl rim). |
P-zoned land typically can't be developed at all without a state-level boundary amendment — a years-long process with no guarantee of approval.
What's my parcel zoned?
Type any Hawaii address — get the zoning code, parcel size, island, and a one-click deep-link to the official record. Free.
Open the lookup →Things buyers and contractors get wrong
"R-5 = I can build whatever I want"
The base zoning code is just the starting point. Overlay districts (special design controls), shoreline setbacks, view-plane corridors, flood zones, and historic-district rules all stack on top and can severely restrict what's actually buildable. Always check the parcel against the full overlay map, not just the base zone.
"BMX means I can convert it to a hotel"
BMX permits residential and commercial — not transient lodging. Hotel use requires either a dedicated H zone (Resort) or a conditional-use permit, which Honolulu has been increasingly reluctant to grant.
"AG-2 with 2 acres lets me build two houses"
AG-2 allows a principal farm dwelling plus a "farm worker" unit if you can demonstrate active production. Two single-family residences for two unrelated families is not the same thing — and code enforcement in Hawaii has gotten more aggressive about this.
Cross-county note: Maui, Hawaii Island, Kauai
The codes above are Honolulu County (Oahu). The neighbor islands use similar but not identical schemes:
- Maui County uses R-1, R-2, R-3 (residential by density), plus B (business), M (industrial), Ag (agricultural), P (public), and INT (interim).
- Hawaii County uses RS (single-family residential, 5/7.5/10/15/20 numbers similar to Oahu's R), RM (multi-family), CG (general commercial), CV (village commercial), A (agricultural), and FA (family agricultural).
- Kauai County uses R (residential), CN/CC/CG (neighborhood / community / general commercial), I (industrial), A (agriculture), and OS (open space).
The IkenaAI Lookup normalizes across counties — it returns whatever the official county record says, so you don't have to memorize three different schemes.