The CSI Divisions List, With the Estimating Notes.

CSI MasterFormat is the numbering system nearly every commercial spec book, subcontractor quote, and owner budget in North America is organized around. The Construction Specifications Institute maintains it; the current structure — often called the 50-division or MasterFormat 2020 format — replaced the old 16-division system back in 2004.

Here's why it matters to your bid and not just your spec binder: when your estimate uses the same cost codes as the documents, scope gaps become visible. An empty line at Division 07 is a question you catch on Tuesday. A missing waterproofing scope with no line to be empty is a check you write in month nine.

The Full List

All Active MasterFormat Divisions

Division numbers 00–49, with the reserved (unused) numbers omitted. Notes reflect commercial building work — TI, build-out, ground-up, and renovation.

Facility construction — where most building dollars live

Div	Name	Estimating notes
00	Procurement & Contracting Requirements	Bid forms, instructions, contract conditions. No cost — but the alternates and unit-price forms live here, so read it first.
01	General Requirements	Supervision, temporary utilities, dumpsters, cleanup, closeout. Routinely 8–12% of a job and the most commonly underestimated division on small commercial work.
02	Existing Conditions	Demolition, hazmat surveys, abatement coordination. On renovation and remediation work this is where the surprises hide — walk the site before you price it.
03	Concrete	Footings, slabs, toppings, precast. Watch for slab infill on plumbing re-routes in TI work — it's small SF but real money.
04	Masonry	CMU, brick, stone. Scaffolding sometimes gets argued between 01 and 04 — decide once, code it consistently.
05	Metals	Structural steel, joists, deck, misc. metals. The misc. metals list (railings, lintels, embeds) is the classic scope-gap zone between 05 and 06.
06	Wood, Plastics & Composites	Rough carpentry, blocking, millwork, casework. Blocking for Div 10 accessories and Div 12 furnishings gets missed constantly.
07	Thermal & Moisture Protection	Waterproofing, insulation, roofing, air barriers, sealants. Firestopping and joint sealants at every trade interface — verify who's carrying them.
08	Openings	Doors, frames, hardware, storefront, glazing. Hardware is its own quote; door/frame/hardware coordination errors are a top punch-list generator.
09	Finishes	Drywall, tile, flooring, acoustical ceilings, paint. On interior build-outs this is often the single largest trade cost — take it off carefully.
10	Specialties	Toilet accessories, signage, fire extinguishers, lockers. Small dollars, but 100% of it shows up on the punch list if it's missed.
11	Equipment	Foodservice, medical, residential appliances. Confirm owner-furnished vs. contractor-installed (OFCI) in writing — this division is where that fight happens.
12	Furnishings	Casework (manufactured), window treatments, FF&E. Often owner-direct; your scope may be receiving and installing only.
13	Special Construction	Cold rooms, clean rooms, pre-engineered structures. Specialty-vendor pricing with long leads — flag the schedule impact, not just the cost.
14	Conveying Equipment	Elevators, escalators, lifts. Two or three real bidders in most markets; get the quote early because it anchors the schedule.

Facility services — the MEP divisions

Div	Name	Estimating notes
21	Fire Suppression	Sprinklers, standpipes. In occupied renovations, head relocation counts drive the price — count them, don't SF it.
22	Plumbing	Fixtures, piping, water heaters. Fixture counts are the quick sanity check against any sub quote.
23	HVAC	Equipment, duct, piping, controls (unless 25). Usually the largest MEP number; verify test & balance and controls are inside someone's quote.
25	Integrated Automation	Building automation systems. Overlaps Div 23 controls and Div 28 — a three-way scope-gap zone. Assign it explicitly.
26	Electrical	Service, distribution, lighting, branch power. Second-biggest MEP number; temporary power usually belongs to 01, not here.
27	Communications	Structured cabling, data, AV. Frequently owner-direct with a vendor — confirm pathway (conduit/boxes) stays in Div 26 scope.
28	Electronic Safety & Security	Fire alarm, access control, cameras. Fire alarm ties to 21/23 sequences; the integration labor is what gets underpriced.

Site & infrastructure

Div	Name	Estimating notes
31	Earthwork	Excavation, grading, shoring, piles. Unit-price risk lives here — rock clauses and unsuitable-soils language deserve a slow read.
32	Exterior Improvements	Paving, curbs, fencing, landscaping. Landscape maintenance periods (90 days? a year?) change the number.
33	Utilities	Site water, sewer, storm, gas, electrical duct banks. Utility-company fees and lead times are the hidden line — they're real cost and real schedule.
34	Transportation	Rail, roadway signaling, transit. Heavy-civil territory; rarely on a building GC's bid form.
35	Waterway & Marine Construction	Docks, dredging, coastal work. Specialty contractors only.

Process equipment — Divisions 40–48

Div	Name	Estimating notes
40	Process Interconnections	Industrial and process work: manufacturing lines, water treatment plants, power generation. If you're a commercial building GC, you'll mostly see these on institutional or industrial RFPs — the equipment is vendor-priced, and your scope is usually rigging, setting, and connecting. Divisions 15–20, 24, 29–30, 36–39, 47, and 49 are reserved and unused.
41	Material Processing & Handling
42	Process Heating, Cooling & Drying
43	Process Gas & Liquid Handling
44–46	Pollution Control / Industry Equipment / Water & Wastewater
48	Electrical Power Generation

Old vs. New

Still Thinking in 16 Divisions?

The 16-division format ran from 1963 to 2004, and plenty of estimators (and plenty of free templates) still use it. The muscle memory translations: old Division 15 Mechanical split into 21 Fire Suppression, 22 Plumbing, and 23 HVAC. Old Division 16 Electrical became 26 Electrical plus 27 Communications and 28 Safety & Security. Old Division 2 Sitework spread across 02 Existing Conditions and the 31–33 series.

Putting It to Work

From Division List to Working Bid

Knowing the divisions is table stakes. The work is wiring them into your estimate so the structure does the checking for you:

Code every line item

Each line carries its division (and ideally a section number, like 09 29 00 for gypsum board). Sorting and subtotaling by code is what turns a pile of numbers into a bid you can defend line by line in a buyout meeting.

Roll up automatically

Division subtotals should compute themselves as you build the estimate — retyping summary numbers is how transposition errors get born at 11pm before a bid deadline.

Compare across jobs

When every estimate uses the same codes, your history becomes a database: your real Division 09 cost per SF on the last five build-outs is the best sanity check any sub quote will ever get.

For a deeper walk-through of what a working estimating template needs beyond the codes — labor/material splits, general conditions, margin vs. markup — see the construction estimating template guide. And if a sub's quote looks off, run it through the free margin vs. markup calculator before you argue.

Questions

CSI Division FAQ