What Is 28 Grams

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Last updated: April 15, 2026

Quick Answer: 28 grams is equivalent to one ounce in the avoirdupois weight system, commonly used in the United States for measuring food, postal items, and precious metals. This measurement is also frequently referenced in cannabis transactions, where it represents a standard unit known as a 'quarter pound.'

Key Facts

28 grams equals 1 ounce in the avoirdupois system
A true ounce is technically 28.3495 grams, but 28 is standard for convenience
In cannabis culture, 28 grams is called a quarter pound
The U.S. Postal Service uses grams and ounces for international shipping rates
Precious metals like gold are measured in troy ounces, which equal 31.1 grams

Overview

28 grams is a common unit of measurement that equates to approximately one ounce in the avoirdupois system, the standard weight system used in the United States for everyday items. While technically an ounce is 28.3495 grams, 28 grams is widely accepted as the rounded equivalent for practical purposes.

This measurement appears frequently in food packaging, postal services, and even in regulated industries like cannabis sales. Understanding the significance of 28 grams helps consumers, retailers, and shippers make accurate comparisons and avoid miscalculations.

28 grams is the standard approximation of one avoirdupois ounce used in retail and commerce in the U.S.
The precise weight of one ounce is 28.3495 grams, but 28 grams is used for simplicity in labeling and transactions.
In the cannabis industry, 28 grams is commonly referred to as a quarter pound, a standard sale unit in legal markets.
International postal services often list weight limits and pricing based on increments of 28 grams for small parcels.
Foods like cheese, meat, and chocolate are frequently sold in 28-gram portions or multiples for consumer convenience.

How It Works

Understanding how 28 grams functions across different systems and industries reveals its practical importance in daily transactions and regulatory compliance. From grocery stores to dispensaries, this unit bridges metric and imperial systems.

Avoirdupois Ounce: The avoirdupois ounce is defined as 28.3495 grams and is used for measuring most goods in the U.S., including food and consumer products.
Rounded Metric Use: For ease, many retailers and postal services use 28 grams as a close-enough approximation of one ounce in international contexts.
Cannabis Measurement: In legal cannabis markets, 28 grams is known as a 'quarter ounce' and is a standard retail quantity for consumer purchase.
U.S. Postal Service: The USPS charges international postage based on weight brackets, with 28 grams marking the first increment above letters.
Food Packaging: Snack foods and specialty items like imported chocolate are often packaged in 28-gram sizes to align with U.S. portion expectations.
Precious Metals: Unlike avoirdupois, gold and silver are measured in troy ounces, which equal 31.1 grams, making 28 grams slightly less than a troy ounce.

Comparison at a Glance

The following table compares 28 grams across different measurement systems and common uses:

Measurement Type	Equivalent in Grams	Common Use Case
Avoirdupois Ounce	28.3495 g	General retail and food sales in the U.S.
Rounded Ounce	28 g	Postal services and informal commerce
Cannabis Quarter	28 g	Legal cannabis retail in states like Colorado and California
Troy Ounce	31.1 g	Gold, silver, and other precious metals
Imperial Quarter-Pound	113.4 g	Meat and produce sold in quarter-pound portions

This comparison shows that while 28 grams is close to one avoirdupois ounce, it differs significantly from troy and imperial quarter-pound measurements. Consumers should be aware of these distinctions, especially when purchasing high-value items like precious metals or regulated substances like cannabis, where weight accuracy is critical for pricing and legality.

Why It Matters

Accurate weight measurement impacts pricing, legality, and consumer trust across multiple industries. A small discrepancy, such as the 0.3495-gram difference between 28 grams and a true ounce, can affect large-scale commerce and regulatory compliance.

Consumer Protection: Regulatory agencies like the FTC require accurate labeling, so selling 28 grams as a full ounce may raise scrutiny in certain contexts.
Cannabis Legalization: In states with legal cannabis, 28 grams is a defined quantity, and exceeding it can trigger felony charges in some jurisdictions.
International Trade: Shipping costs from the U.S. to Europe often start at 28 grams, making this a key threshold for small businesses.
Dietary Tracking: Nutrition labels often list serving sizes in grams, and 28 grams is a common benchmark for fats and snacks.
Pharmaceuticals: Some medications, especially in research, are dosed in milligrams per kilogram, requiring precise gram conversions.
Historical Context: The avoirdupois system dates back to the 13th century, and 28 grams remains a legacy unit in modern commerce.

From grocery shopping to international shipping, 28 grams plays a surprisingly central role in everyday life. Recognizing its various applications helps consumers make informed decisions and avoid misunderstandings in both legal and commercial settings.