NAICS code for professional services: sector 54 and the six-digit code for your firm

This page is for owners of professional firms who've been asked for a NAICS code (by a bank, an insurer, a client's vendor portal, a grant or SAM.gov) and only know they're "professional services," and for sellers who target professional firms. It maps the sector, shows how to pick the six-digit code, and flags the look-alikes.

What sector 54 covers

The Census Bureau defines the sector as establishments that "specialize in performing professional, scientific, and technical activities for others," activities that "require a high degree of expertise and training." Sector 54 has one subsector, 541, and nine industry groups:

The sector definition also draws the boundary that trips people up most: establishments providing "a range of day-to-day office administrative services, such as financial planning, billing and recordkeeping, personnel supply, and physical distribution and logistics" are in sector 56, not 54.

How to choose your six-digit code

1. Name what the client pays for. Advice, design, analysis, representation or research, sold for a fee. That points to a group above.
2. Go to six digits inside the group. Use the code for the service with the most revenue, and list the others as secondary codes. Pages for consulting, IT consulting and architecture cover the common splits.
3. Use 541990 only when nothing else fits. The Census definition lists what it holds: appraisal other than real estate, arbitration and mediation outside law offices, business brokers, construction estimating, consumer credit counseling, commodity and pipeline inspection, weather forecasting, handwriting analysis and quantity surveying.

Then check the look-alikes. Each of these sounds like a professional service but is classified elsewhere:

The medical row matters for professional corporations and PLLCs: the legal form says nothing about the industry. A medical PC is classified with physicians' offices (621111), a law PLLC with lawyers (541110).

The SIC codes

There's no single SIC code for professional services. Sector 54 was assembled from parts of SIC Division I, mainly Major Groups 73 (business services), 81 (legal services) and 87 (engineering, accounting, research and management services). From the Census concordances:

SIC 8999 shows why converting a catch-all is risky: it feeds 16 NAICS codes, from music publishers to environmental consultants. Check any code in the NAICS to SIC converter.

How many professional services firms there are

County Business Patterns 2023 counts 989,182 establishments in sector 54, with 10,401,442 employees and $1.11 trillion in annual payroll, about $107,140 per employee (our calculation). The sector is mostly small offices: 706,067 establishments (71.4%) have fewer than five employees, and 81,964 (8.3%) have 20 or more. Research and development is the exception, averaging 44.8 employees per establishment.

CBP counts locations with paid employees. Solo practitioners without staff aren't in these figures, and a firm with offices in ten cities counts ten times. It uses NAICS 2017 codes; the sector 54 codes didn't change in 2022.

SBA size standards and federal buying

Each six-digit code has its own size standard. A sample from SBA's table effective 17 March 2023, still current in the eCFR on 28 October 2026, in average annual receipts unless shown as employees:

Federal contract obligations under sector 54 codes were $240.70 billion in fiscal 2024 and $226.34 billion in fiscal 2025, from USAspending.gov. The largest codes in fiscal 2025 were 541330 engineering ($51.68 billion), 541715 research and development ($46.39 billion), 541512 computer systems design ($31.70 billion), 541519 other computer services ($24.86 billion) and 541990 ($11.92 billion). Retired codes still appear: 541712 and 541710, research codes from earlier NAICS editions, carried $8.81 billion and $8.58 billion, so check old codes when you search award history.

GSA's OASIS+ contract for professional services shows how broad the federal definition is: its NAICS page, updated 15 June 2026, lists 13 domains, from Management and Advisory to Social Services, and 541990 appears in every one.

Where the code is used, and what a wrong one costs

• Federal bids. Each solicitation names one code and its size standard. A consultancy registered only under 541990 misses work posted under 541611.
• Insurance. Professional liability carriers group risks by profession, so the code should match the service you'd describe to an underwriter.
• Tax returns. Schedule C shortens several codes, for example 541600 for all consulting and 541510 for computer services; Form 1120 keeps the six-digit detail.

Finding professional services firms by code

Most professional firms are private partnerships, PCs or LLCs, so EDGAR covers few of them, and those it covers are filed under codes that don't always match:

For private firms, state licensing boards (bar associations, boards of accountancy, engineering and architecture boards) publish license lookups, and USAspending's recipient search names federal contractors by code. Bebop finds firms from a description, such as CPA firms with 20 to 100 employees in Texas that serve manufacturers.

Worked example

Illustrative example. The firm and its figures are invented; the standards are SBA's.

Bayside Advisory Group (bayside.example) earned $2.2 million last year: $0.8 million from bookkeeping, $0.7 million from tax preparation, $0.4 million from management consulting and $0.3 million from payroll services.

1. Group. Accounting, tax, bookkeeping and payroll are $1.8 million of $2.2 million (81.8%), so the firm sits in 5412.
2. Six digits. Bookkeeping is the largest single service (36.4%), so the primary code is 541219, Other Accounting Services, with 541213, 541214 and 541611 as secondary codes. If a partner becomes a CPA and the firm starts audits, 541211 would apply to that work.
3. SIC. 8721, Accounting, Auditing, and Bookkeeping Services.
4. Size. Five-year average receipts of $1.9 million are under every standard involved: $25.0 million for 541219 and 541213, $39.0 million for 541214 and $24.5 million for 541611.

Next step: look up the six-digit code for any service you add in the NAICS code lookup.