16 CFR § 500.18 - SI metric prefixes.

---
identifier: "/us/cfr/t16/s500.18"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "16 CFR § 500.18 - SI metric prefixes."
title_number: 16
title_name: "Commercial Practices"
section_number: "500.18"
section_name: "SI metric prefixes."
chapter_name: "FEDERAL TRADE COMMISSION"
subchapter_number: "E"
subchapter_name: "RULES, REGULATIONS, STATEMENT OF GENERAL POLICY OR INTERPRETATION AND EXEMPTIONS UNDER THE FAIR PACKAGING AND LABELING ACT"
part_number: "500"
part_name: "REGULATIONS UNDER SECTION 4 OF THE FAIR PACKAGING AND LABELING ACT"
positive_law: false
currency: "2026-03-24"
last_updated: "2026-03-24"
format_version: "1.1.0"
generator: "[email protected]"
authority: "15 U.S.C. 1453, 1454, 1455."
regulatory_source: "59 FR 1872, Jan. 12, 1994, unless otherwise noted."
cfr_part: "500"
---


# 500.18 SI metric prefixes.

The following chart indicates SI prefixes that may be used on a broad range of consumer commodity labels:

| Prefix | Symbol | Multiplying factor |
| --- | --- | --- |
| Kilo- | k | x 10 |
| Deca- | da | × 10 |
| Deci- | d | × 10 |
| Centi- | c | × 10 |
| Milli- | m | × 10 |
| Micro- | µ | × 10 |
| 10=100; 10=1000; 10=0.1; 10=0.01. |  |  |
| Thus, 2 kg=2 × 1000 g=2000 g, and 3 cm=3 × 0.01 m=0.03 m. |  |  |