General

CSI MasterFormat

The standard numbering system organizing construction specifications into 50 divisions and thousands of sections.

CSI MasterFormat is a hierarchical numbering system maintained by the Construction Specifications Institute that organizes construction specifications and project information. Divisions 00 (Procurement) through 14 cover general project requirements and architectural scope. Divisions 21 through 28 cover MEP and fire protection. Divisions 31 through 49 cover sitework, transportation, utilities, and process equipment.

MasterFormat is the standard reference for organizing project specifications, estimating workbooks, and project filing systems on commercial construction. Most published price-book references (RSMeans, etc.) and most commercial bid documents follow MasterFormat numbering. Knowing the divisions speeds bid review and estimate organization.

Frequently asked questions

What does CSI MasterFormat organize?+

Construction specifications and project information into a hierarchical numbering system: 50 divisions, hundreds of sections, thousands of subsections. It is the standard for organizing commercial project documentation.

How many divisions are in MasterFormat?+

50 divisions in current MasterFormat (00 through 49). Divisions 00-14 cover procurement and architectural scope. 21-28 cover MEP and fire protection. 31-49 cover sitework, transportation, utilities, and process equipment.

Do I need to know MasterFormat as a small contractor?+

For commercial work, yes. Bid documents, specs, and most estimating references organize by MasterFormat division. Residential work generally does not require MasterFormat fluency, but some custom-home builders use simplified versions.

Related terms

Scope of Work

The written description of all tasks, materials, and deliverables the contractor agrees to perform on the project.

Bid

A contractor's formal price proposal to perform a defined scope of work, usually in response to a bid invitation.

Estimate

A contractor's informational projection of project cost. Non-binding and revisable; differs from a firm bid.

Submittal

A contractor-prepared document (shop drawing, product data, sample) submitted for design-team review before fabrication.