If your business involves selling goods by weight or measure, understanding “legal for trade” is essential. This certification ensures that your transactions comply with federal and state laws. It will also instill trust in your customers and protect your bottom line.
In this guide, we’ll address common questions we receive regarding “legal-for-trade” definitions, applications, implications, and even some history—all in simple, easy-to-understand terms.
What is “Legal for Trade” and Why is it Important?
“Legal for trade” is a certification that applies to measuring devices, such as scales, used in commercial transactions where goods are sold by weight, length, or other specific measurements. For example, a legal-for-trade scale ensures that a pound of sugar weighs the same whether purchased in Bangor, Maine, or Albuquerque, New Mexico.
For a measuring device to be considered “legal for trade,” both of these must be true: (1) the manufacturer’s model passes specific standards compliance tests for the class of device through an accredited lab, and (2) the unit itself complies (and continues to comply throughout its service) with field test tolerances through a government-approved inspector. We will cover both of these in more detail below.
The whole point of having “legal-for-trade” devices is to make sure the transactions that use them are fair to all involved parties, by law. Since laws require them for commerce, there are fines and other penalties for non-compliance.
Who Decides What is “Fair” in Commercial Trade?
“Fairness” comes from written standards, determined by various global governing bodies, and laws requiring adherence to those standards. Throughout history, many jurisdictions have created weights and measures standards to regulate trade within them. These were eventually replaced by the global SI system of units, introduced in 1875 through an international treaty signed by 17 nations, including the United States.
Nearly 40 years earlier, the United States Congress established the Office of Weights and Measures (OWM) to ensure fairness in inter-state commercial transactions, fulfilling its Constitutional mandate. (Article 1, Section 8 of the U.S. Constitution grants Congress the power to ‘fix the Standard of Weights and Measures.’) Originally part of the Department of the Treasury, it still operates today under the National Institute of Standards and Technology (NIST) within the Department of Commerce.
How Does my Device Obtain “Legal for Trade” Certification?
In the United States, scales are certified as “legal for trade” once they pass tests established by the National Conference on Weights and Measures (NCWM), through the National Type Evaluation Program (NTEP). The NCWM, a non-profit organization, oversees the administration of NTEP tests to ensure scales meet the accuracy class standards outlined in NIST Handbook 44. You can read more about Handbook 44 requirements and accuracy classes in our article, Load Cell Classes: NIST Requirements.
Again, full certification is a two-step process.
Step One: Model Compliance
As mentioned earlier, manufacturers must submit a working sample for each design to the NTEP to prove compliance with NIST requirements. Independent, NTEP-approved laboratories around the US perform these tests. A passing model receives a Certificate of Compliance with a unique number. The NCWM maintains a public database of these certificate numbers that buyers can reference.
Only the final product requires certification. Individual scale components themselves do not require it. Read this FAQ question for more information on this point.
Step Two: Unit Verification
Before a scale can be used for trade, its owner must have the state’s local weights and measures department verify its compliance. During this process, a state-approved inspector confirms the scale model’s certification, tests its calibration and performance against the model’s specifications, and ensures compliance with all applicable trade laws. If the scale meets all requirements, the inspector seals the calibration setting with a sticker as proof of compliance.
Verification is legally required at regular intervals, based on how frequently the scale is used. In some states, inspections may also occur randomly. This makes regular calibration essential. By routinely calibrating the scale with known, standard weights, merchants can prevent performance drift and avoid errors that could become irreparable over time. Regular calibration can also avoid costly fines.
When Does my Scale Require NTEP Certification as “Legal for Trade”?
A scale requires legal-for-trade certification in these situations:
1. Final Sale/Transaction
When the scale used to weigh the final product—the weight of which will be printed on labels or used to calculate the price for the customer—it must be NTEP-certified. Examples include:
- A deli counter scale that prints a price label.
- A shipping scale where customers are charged by weight.
- A packaging line scale that puts the net weight on the retail product label.
2. Intermediate Steps That Affect Billing
If there is a step in the production or distribution process where the weight is directly used for a commercial transaction, that scale must also be NTEP-certified. For instance, if you sell intermediate quantities to a distributor based on weight before final packaging, the device measuring that weight must have legal-for-trade certification.
When is NTEP Certification Not Required for a Scale?
Scales used for the following situations are not required by law to receive a Certificate of Compliance:
1. Internal Quality Control or Inventory Tracking
If a scale is only used internally (e.g., to track inventory, to portion out ingredients within the factory, or to maintain internal process control) and does not directly determine a weight for a sale, NTEP certification is not strictly required. These scales can be non-certified so long as the final “legal-for-trade” measurement is done on an NTEP-certified device before a sale or labeling of the net weight.
2. Research & Development (R&D)
Scales used for product development, lab testing, or other non-commercial activities aren’t typically required to be NTEP-certified.
3. Non-Commercial Weighing
Any scenario where weight is measured but not used for a commercial exchange (e.g., measuring for personal or educational use) doesn’t need “legal-for-trade” certification.
What Happens if My Scale is Noncompliant? Corrective Action and Consequences
When discussing corrective action for non-compliance, it helps to understand the terms related to tolerance levels. Scales are evaluated against two sets of standards:
- Acceptance tolerances: These are the stricter accuracy standards a scale must meet during certification testing.
- Maintenance tolerances: These are looser standards applied during verification testing. They typically are twice the acceptance tolerances since these tests occur in less controlled environments.
If an inspector finds a scale non-compliant during verification testing, the owner usually has 30 days to fix the issue. After repairs, the scale must meet the stricter acceptance tolerances before it can be used again. Regular calibration can help prevent scales from drifting so far out of tolerance that reconditioning becomes necessary.
Failure to comply with these requirements can lead to serious penalties, which vary by state. These may include significant fines, confiscation of equipment, or even business closure in cases of repeated violations.
Conclusion
This article covers many of the questions we receive regarding legal-for-trade scale certification and compliance. If you have further questions or are interested in maintenance calibration, please feel free to contact us.
