HS Code 90.31 – Measuring or checking instruments, appliances and machines, n.e.c. or included in this chapter; profile projectors

HS code 9031 is a 4-digit heading in the Harmonized System that covers: Measuring or checking instruments, appliances and machines, n.e.c. or included in this chapter; profile projectors. Heading 9031 serves as a crucial residual classification within Chapter 90, encompassing a wide array of measuring or checking instruments, appliances, and machines not specifically provided for elsewhere in the chapter. This makes it a 'basket' heading for precision measuring and inspection equipment that doesn't fit into more specialized categories like analytical instruments (9027) or electrical meters (9030). The scope is broad but defined by exclusion, covering devices for dimensional measurement, surface quality assessment, material testing, and other general checking functions. Prominent examples include Coordinate Measuring Machines (CMMs), profile projectors (optical comparators), hardness testers, roughness testers, and various specialized test benches. This heading is indispensable for quality control, metrology, and manufacturing processes across virtually all industrial sectors. Proper classification under 9031 is vital for trade compliance, ensuring correct tariff application, avoiding delays, and adhering to product-specific standards. Historically, this category has adapted to technological advancements, incorporating laser, vision, and robotic systems into traditional mechanical measurement. As part of Section XVIII, this heading reinforces the chapter's overarching focus on precision and accuracy in measurement and inspection, acting as the catch-all for instruments that ensure product quality and conformity in global trade.

Coordinate measuring machines (CMMs), Optical comparators (profile projectors), Roughness testers, Hardness testers, Thickness gauges (non-radioactive), Laser measurement systems (for dimensions), Surface profilers, Gauge blocks, Ring gauges, Plug gauges, Bore gauges, Torque wrenches with measuring display, Vision inspection systems (machine vision for quality control), Test benches for engines, Test benches for pumps, Gear testing machines, Spring testing machines, Balancing machines (for rotating parts), Non-contact dimension measuring devices, Robotic inspection systems, Ultrasonic flaw detectors (industrial), Eddy current testing equipment, Universal material testing machines (tensile/compression), Leak detection machines (industrial), Autocollimators, Interferometers (for industrial measurement), Roundness measuring machines, Contour measuring machines, Flatness measuring machines

Traders frequently misclassify products under heading 9031 because of its 'n.e.c.' (not elsewhere specified) nature. A common mistake is to classify instruments here that actually belong in more specific headings within Chapter 90, such as analytical instruments (9027) or electrical measuring devices (9030). For example, a specialized sensor for measuring a specific chemical property might be incorrectly placed in 9031 instead of 9027. Another error involves parts and accessories of machine tools (8466) being classified as complete measuring machines. Furthermore, machines having individual functions (8479) that might incorporate some measuring elements, but whose primary purpose isn't measuring or checking, can be confused. The key is to first rule out all other specific 90XX headings before resorting to 9031.

In 2025, the top exporters of HS code 9031 in UN Comtrade data were Germany ($10.7B, 15% of world exports), China ($8.6B) and the United States ($8.2B). World exports came to about $69.5B, adding countries' reported figures and partner-based estimates for those that did not report (UN Comtrade data). Countries that did not report 2025 data are estimated from partner records, which can understate them.

In 2025, the top importers of HS code 9031 in UN Comtrade data were China ($16.1B, 22% of world imports), the United States ($7.2B) and South Korea ($4.9B). World imports came to about $72.0B, adding countries' reported figures and partner-based estimates for those that did not report (UN Comtrade data). Countries that did not report 2025 data are estimated from partner records, which can understate them.

HS code 9031 is a 4-digit heading under Chapter 90 of the Harmonized System. The first 2 digits (90) identify the chapter, and digits 3-4 (31) specify the heading. This code contains multiple 6-digit subheadings for precise product classification.