You opened the NAICS lookup tool. You typed “IT.” You got 47 codes. Three of them are 541512, 541511, and 541513. They look nearly identical. Federal agencies use them differently. The SBA (Small Business Administration) assigns different size standards to some of them. Picking the wrong one as your primary code can cost you set-aside eligibility on contracts your business should win.
This guide breaks down the seven NAICS (North American Industry Classification System) codes that matter most for IT contractors, explains what work fits each one, and walks you through a decision framework for choosing your primary code and building out your secondary list.
Quick Answer: Which NAICS Code for IT Services?
Most IT contractors should claim 541511 (Custom Computer Programming) if their core work is writing or modifying code for clients, or 541512 (Computer Systems Design) if they design and integrate technology solutions. Managed IT, hosting, and cloud infrastructure fits better under 518210. Your primary code should match the work that generates most of your revenue. Secondary codes cover everything else you do.
Before You Pick: Who Assigns NAICS Codes?
There are two NAICS-selection acts and it matters that you do not confuse them.
The contracting officer assigns the NAICS code to each solicitation. Per FAR 19.102(b)(1), “contracting officers shall assign one NAICS code and corresponding size standard to all solicitations, contracts, and task and delivery orders.” The CO picks one code per solicitation, based on the industry that best describes the principal purpose of the work. That single code determines who can bid as a small business on that specific contract. The CO’s designation is final unless a bidder appeals it through the NAICS code appeal process described at FAR 19.103. (A size protest, which challenges whether a specific bidder is actually small under the assigned NAICS code, is a separate remedy with separate rules.)
You select the NAICS codes that appear on your SAM.gov registration. Your registration can list multiple codes. One is your primary; the rest are secondary. These codes do not determine eligibility on any specific contract. They determine which agencies and contracting officers can find your business during market research, and they determine which set-aside solicitations you can bid on (because the solicitation’s NAICS must be on your registration).
Two separate acts. The CO controls the solicitation; you control the SAM registration. Your job is to make sure the codes on your SAM registration cover the work you actually do, so when a CO assigns a NAICS code matching your capability, you are eligible to bid.
Why Your Primary NAICS Code Matters
Your primary NAICS code does three things that directly affect your contracting opportunities.
It determines your SBA size standard. The SBA sets revenue thresholds for each NAICS code. If your annual receipts (averaged over the past five years) fall below that number, you qualify as a small business under that code. That qualification unlocks set-asides, meaning contracts reserved for small businesses only. The IT codes covered here carry size standards ranging from $19 million to $40 million in average annual receipts (as of 2026, per 13 CFR 121.201). Verify exact figures at sba.gov/document/support-table-size-standards before you rely on them for a specific procurement.
It determines which set-asides you can bid on. When an agency posts a set-aside using NAICS code 541511, only businesses that have 541511 on their SAM.gov (System for Award Management) registration can bid as a small business. If you registered under 541512 only, you cannot bid on that 541511 set-aside, even if the work is in your wheelhouse.
It shapes how agencies find you. Contracting officers search SAM.gov by NAICS code when they are building market research reports and finding businesses to notify about upcoming work. The codes on your registration determine who sees you.
The Seven IT NAICS Codes, Decoded
These codes come from the official NAICS directory at census.gov/naics. Definitions are paraphrased for clarity; check the official source before citing them in a proposal.
| NAICS Code | Title | Size Standard (2026) | Best Fit | Set-Aside Competition |
|---|---|---|---|---|
| 541511 | Custom Computer Programming Services | $34.0M | Writing, modifying, or testing custom software for clients | High. Large pool of eligible bidders. |
| 541512 | Computer Systems Design Services | $34.0M | Designing and integrating hardware, software, and network systems | Very high. The most common IT set-aside code. |
| 541513 | Computer Facilities Management Services | $37.0M | Running or managing a client’s IT operations on-site or remotely | Moderate. More specialized, fewer bidders. |
| 541519 | Other Computer Related Services | $34.0M | IT work that does not fit the above: training, repair, technical support | Low. Catch-all code, less frequently used for large set-asides. |
| 518210 | Computing Infrastructure Providers, Data Processing, Web Hosting, and Related Services | $40.0M | Cloud hosting, data centers, web hosting, managed cloud services | Moderate. Growing as cloud mandates expand. |
| 541690 | Other Scientific and Technical Consulting Services | $19.0M | IT advisory and consulting that crosses into scientific or engineering analysis | Low. Niche code, used in specific civilian agency contracts. |
| 541618 | Other Management Consulting Services | $19.0M | IT advisory that crosses into organizational or management consulting | Low to moderate. Used when the deliverable is a management recommendation, not a technical solution. |
Size standards reflect average annual receipts thresholds per the SBA Table of Size Standards at 13 CFR 121.201 (current as of 2026). 541513 carries a higher $37M standard reflecting the SBA’s distinction for facilities management. 541690 and 541618 carry lower $19M standards because the SBA classifies consulting work separately from core IT services. Always verify the current figure at sba.gov/document/support-table-size-standards before relying on it for a specific procurement.
A Closer Look at Each Code
541511: Custom Computer Programming Services
This code covers businesses whose primary work is writing, modifying, or testing software specifically for a client’s use. Think software developers building a custom case management system for an agency, or a team writing Python scripts to automate a data pipeline. The key word is “custom.” You are not selling packaged software; you are building something to the client’s specification.
Typical federal buyers: Department of Defense (DoD) program offices, civilian agencies undergoing digital transformation, and agencies with aging legacy systems they need modernized.
The SBA size standard is $34.0 million in average annual receipts. Competition on 541511 set-asides is high because this code captures a large share of the federal software development market. A four-person development shop will face hundreds of eligible competitors on a public set-aside. To stand out, you need a focused capability statement and targeted outreach to contracting officers before the solicitation drops.
541512: Computer Systems Design Services
This is the most commonly used IT code in federal contracting. It covers businesses that design integrated hardware, software, and network systems to meet a client’s specifications. If 541511 is “we write the code,” 541512 is “we design the whole system and make all the pieces work together.”
Typical federal buyers: IT modernization program offices, agencies building enterprise networks, and civilian agencies running large-scale infrastructure projects.
The $34.0M size standard matches 541511. Because 541512 is so broadly defined, it is the default code many contractors pick without thinking carefully. That makes it the most saturated for small business set-aside competition. If your work genuinely fits 541511 or 541513 more precisely, claiming one of those as your primary code may improve your competitive position on targeted set-asides.
541513: Computer Facilities Management Services
This code fits businesses that manage a client’s computing facilities, whether on-site or remotely. Managed IT service providers (MSPs) fall here if their primary work is operating and managing the client’s technology environment rather than designing or building it. Examples include help desk operations, network operations center (NOC) management, and IT infrastructure management contracts.
Typical federal buyers: agencies outsourcing their IT operations, military bases contracting out their on-site IT support, and civilian agencies running managed services vehicles.
The $37.0M size standard is slightly higher than the core 541xxx codes, reflecting the operational scale typical of facilities management work. Set-aside competition is moderate because the managed services model requires more operational capacity than a typical software shop, which filters out some smaller competitors.
541519: Other Computer Related Services
This is the catch-all code for IT work that does not fit 541511, 541512, or 541513. It covers computer training, computer repair, and other technical support services. Most IT contractors should not use 541519 as their primary code unless their business is specifically one of those narrower activities. Agencies use it less frequently for major set-aside procurements.
518210: Computing Infrastructure Providers, Data Processing, Web Hosting, and Related Services
This code was updated in recent NAICS revisions to reflect the shift to cloud computing. It covers cloud hosting providers, data center operators, web hosting businesses, and companies whose primary work is providing computing infrastructure as a service. If your business hosts federal applications, runs cloud environments for agencies, or provides managed cloud services, this code may be your best primary.
The $40.0M size standard for 518210 is the highest of the seven codes in this guide, reflecting the capital-intensive nature of infrastructure businesses. Federal cloud mandates (FedRAMP, cloud-first policies) are driving more 518210 procurements through vehicles like the GSA (General Services Administration) MAS (Multiple Award Schedule) and large IDIQ (Indefinite Delivery, Indefinite Quantity) contracts.
541690 and 541618: When IT Crosses Into Consulting
Some IT work slides into management or scientific consulting territory. An IT security advisory that recommends organizational changes may belong under 541618 (Other Management Consulting Services). A data analytics service that uses scientific methods may belong under 541690 (Other Scientific and Technical Consulting Services). Both carry a $19.0M size standard, which is meaningfully lower than the $34M-$40M standards on the core IT codes. That matters if you are growing: a firm that fits both 541512 and 541618 will hit small-business status under 541512 ($34M) but lose it under 541618 ($19M) at lower revenue.
Most pure IT shops do not need these as primary codes. They become useful as secondary codes when you want to be visible on consulting-heavy contracts.
How to Pick Your Primary NAICS Code
Your primary NAICS code should reflect the work that generates the largest share of your revenue. Follow this decision path.
Step 1: Describe your core service in one sentence. What do you do for most of your clients, most of the time? Write it down without looking at any NAICS codes.
Step 2: Match that sentence to the code descriptions above.
- If it is “we write custom software” or “we build software applications for clients,” your primary is 541511.
- If it is “we design technology systems and integrate hardware and software,” your primary is 541512.
- If it is “we manage our clients’ IT operations and keep their systems running,” your primary is 541513.
- If it is “we host applications or run cloud infrastructure for clients,” your primary is 518210.
- If it is “we provide IT advisory and strategic consulting,” look at 541618 (Other Management Consulting Services), then verify the size standard fits your revenue.
Step 3: Check your size standard position. Average your last five years of annual receipts. Compare that number against the size standard for your intended primary code. The 5-year averaging rule lives at 13 CFR 121.104(c)(1); it has applied to receipts-based size determinations for federal contracting since the Runway Extension Act, with the final transition completed January 6, 2022. If you are within 20% of the size threshold, read the parent article on SBA size standards for the averaging methodology in full.
Step 4: Check the competition density. If your primary code is 541512 and you are a four-person shop competing against hundreds of other small businesses, consider whether 541511 or 541513 more accurately describes your work. Precision can reduce your set-aside competition pool without reducing your visibility.
Step 5: Confirm the code is active in SAM.gov. Log into SAM.gov and verify you can add your intended primary code to your registration before you finalize your choice.
How Many Secondary Codes Should You List?
Secondary NAICS codes expand your visibility on SAM.gov. There is no federal rule limiting how many you can list, but the practical answer for most IT contractors is three to six secondary codes total (including primary).
The logic: add a secondary code only if you can genuinely perform work under that code at a competitive level. Agencies use NAICS codes during market research. If a contracting officer sees your business on a list for a specific code and reaches out, you need to be able to back it up with a real capability. Padding your SAM registration with every IT code on the list does not help you win work. It dilutes your profile and wastes contracting officers’ time.
A typical small IT firm might list:
- Primary: 541511 (custom programming, their main revenue source)
- Secondary: 541512 (they also do systems integration work)
- Secondary: 541519 (they also provide technical training)
For a full walkthrough of how NAICS codes work in your SAM.gov registration, see the NAICS codes for government contracting guide.
What If You Outgrow Your Size Standard?
Growing past your size standard does not automatically disqualify you from existing small business set-asides, but it affects new awards. The SBA uses a 5-year average of annual receipts to determine size under 13 CFR 121.104(c)(1). That means a business that crosses the threshold in one strong revenue year is not automatically reclassified. The 5-year average smooths out spikes.
But plan ahead. If your revenues are trending toward the size standard for your primary NAICS code, you have options:
- Recertify annually through SAM.gov and track your 5-year average carefully.
- Evaluate whether a different NAICS code with a higher size standard better fits your work. Moving from 541512 ($34M) to 518210 ($40M) (if you have grown into cloud services) can extend your small business eligibility while accurately reflecting your current business model.
- Begin building relationships with large prime contractors. As you approach the size limit, teaming as a subcontractor on large contracts can sustain revenue while you prepare to compete in the unrestricted space.
The SBA size standards guide on this site covers the receipts averaging rules in full: SBA size standards for small businesses.
Frequently Asked Questions
Can I use 541512 and 541511 both on my SAM.gov registration?
Yes. SAM.gov allows you to list multiple NAICS codes. You designate one as your primary and the rest as secondary. List 541511 as primary and 541512 as secondary if custom programming is your core service and systems integration is a supporting capability. Both codes will appear in database searches, and you can bid on set-asides for either, as long as the solicitation’s assigned NAICS code is on your registration.
Does my NAICS code affect which GSA schedules I can apply for?
Yes. The GSA (General Services Administration) MAS (Multiple Award Schedule) program organizes contracts by NAICS code. When you apply for a MAS contract, you apply under specific SINs (Special Item Numbers) that correspond to NAICS codes. Your registered NAICS codes in SAM.gov should match the SINs you intend to pursue. Check the current GSA MAS solicitation at gsa.gov/buy-through-us/purchasing-programs/multiple-award-schedule for the SIN-to-NAICS mapping that applies to your category.
What is the difference between 541511 and 541512 in practice?
541511 is for businesses whose primary deliverable is code: custom applications, scripts, software modifications. 541512 is for businesses whose primary deliverable is a functioning system: a network, an integrated technology environment, a hardware-and-software solution. A software development shop is 541511. An IT integrator is 541512. Many businesses do both; pick whichever generates more revenue as your primary.
Can I change my primary NAICS code after I register on SAM.gov?
Yes. You can update your SAM.gov registration at any time to change your primary or secondary NAICS codes. Changes take effect after SAM.gov processes your update, which typically takes one to three business days but can take longer if entity validation is triggered. The key rule: you must recertify your small business size status at the time of each offer under the specific NAICS code on that solicitation, not just at registration time. Recertification rules live at 13 CFR 121.404.
I run a cybersecurity firm. Which NAICS code fits?
Cybersecurity services sit across several codes depending on what you deliver. Network security monitoring and management fits 541513. Security software development fits 541511. Security architecture and system design fits 541512. Cybersecurity consulting and risk assessments fit 541690 or 541618. Many cybersecurity firms list 541512 as their primary with 541513 and 541511 as secondaries. Match the code to your primary revenue-generating service.
Does 518210 require FedRAMP authorization?
NAICS code 518210 does not by itself require FedRAMP authorization. FedRAMP (Federal Risk and Authorization Management Program) is a security authorization framework required when a cloud service provider wants to sell cloud services to federal agencies. If you host federal data or run cloud environments for agencies, FedRAMP authorization is expected regardless of your NAICS code. 518210 simply classifies your business type. FedRAMP classifies your security posture.
What if my work spans several of these codes equally?
Pick the code that covers your highest-revenue service line and use it as your primary. For set-aside purposes, the contracting officer designates a single NAICS code per solicitation under FAR 19.102(b)(1). Your job is to ensure that code is on your SAM registration and that your primary code reflects your core business so your size determination is accurate. When revenues are genuinely split, choose the code with the most federal contracting activity in your target market and treat it as primary. You can always revise as your business evolves.
What if I think the contracting officer assigned the wrong NAICS code to a solicitation?
You can appeal the NAICS code designation. The appeal procedure is at FAR 19.103 and the SBA Office of Hearings and Appeals (OHA) rules at 13 CFR 134. The appeal must be filed within 10 calendar days after the solicitation is issued. The appeal is decided by the SBA OHA. If you believe the CO’s NAICS choice has a higher size standard than the work actually warrants (cutting you out of small-business competition) or a lower size standard than the work warrants (creating size-protest risk for your bid), the appeal is your formal remedy.
Next Steps
Start with your SAM.gov registration. Log in, review your current NAICS codes, and compare them against the descriptions above. If your primary code does not match your core revenue source, update it.
Then read these two guides for the full picture:
- NAICS codes for government contracting: the complete guide to how NAICS codes work, how agencies use them, and how to research codes for your industry.
- SBA size standards: a plain-English breakdown of how size standards are calculated, the 5-year averaging rule, and what happens when you grow past the threshold.
