Cannabis Weight Measurements Explained

The units, in order

Cannabis is sold in standardized weight increments. From smallest to largest:

The terminology varies by region and generation. "Zip" for ounce is common in some areas, "O" in others; "quad" or "Q" for quarter is widespread; "dub" originally meant a $20 bag (the amount varied by market) but increasingly refers to 2 grams.

The math behind the numbers

One avoirdupois ounce (the standard US ounce) equals 28.3495 grams. Cannabis culture rounds this to 28 grams flat for convenience. From there:

• An eighth = 28 / 8 = 3.5g (technically 3.54375g; rounded down)
• A quarter = 28 / 4 = 7g (technically 7.0875g; rounded down)
• A half = 28 / 2 = 14g (technically 14.175g; rounded down)
• An ounce = 28g flat (technically 28.3495g; some retailers sell at exactly 28.35g, most round to 28)

The rounding favors the seller by a small margin — about 1% lighter than the true ounce. In states with regulated cannabis markets, packaging requirements typically allow for this rounding within specified tolerances. For consumers, the practical effect is small: an "eighth" is essentially 3.5 grams regardless of whether the exact math says 3.54.

Concentrates, edibles, and other products are typically sold in metric units (grams or milligrams) without the eighth/quarter convention. The fractional system applies primarily to flower.

Why imperial fractions?

The fraction-of-an-ounce system is a quirk of cannabis culture, not an inherent property of the plant. Several factors contributed to its dominance:

Historical pricing

Cannabis markets historically operated in imperial units because the US uses imperial measurements for retail sales. An eighth-ounce was a convenient amount — enough for a few sessions, small enough to be affordable, easy to weigh on common scales. The unit predates contemporary regulated markets by decades.

Mathematical convenience

The fractions divide evenly. An ounce splits cleanly into halves, quarters, and eighths. Smaller fractions (sixteenths) exist but are less commonly used. The decimal grams (3.5, 7, 14, 28) emerge naturally from the math.

Cultural inertia

The terminology has been passed through generations of cannabis culture. Regulated state markets that emerged in the 2010s could have adopted metric-only units but generally maintained the existing terminology because it was what consumers and retailers already used.

Practical convenience

For everyday use, "an eighth" is more useful shorthand than "3.5 grams." The fraction names communicate quantity quickly without consumers needing to calculate decimal grams.

What each amount looks like

Cannabis flower density varies — indoor-grown often denser than outdoor, some strains naturally fluffier than others — so the same weight can produce visibly different volumes. Rough visual references for typical commercial flower:

• 1 gram: Roughly the size of a grape, or one to two large buds depending on density. Enough for approximately 2-4 joints of average size, or 4-8 bowls in a small pipe.
• Eighth (3.5g): Fits comfortably in a small jar or container. Approximately 5-10 average joints worth, or a week's casual consumption for a moderate user.
• Quarter (7g): A small handful of buds. Typically 10-20 joints worth, or 2-4 weeks of casual consumption.
• Half (14g): A meaningful jar. Most casual users find a half-ounce lasts a month or more.
• Ounce (28g): A substantial quantity. Often sold in a larger sealed jar or pouch. For most consumers, an ounce is a stock-up purchase rather than a typical individual purchase.

These are rough guidelines. Individual consumption patterns vary enormously, and the visible volume depends on bud density, moisture content, and how the flower has been packaged.

How pricing typically scales

Cannabis pricing typically follows quantity discounts — bulk purchases cost less per gram than single grams. In regulated markets, typical price scaling:

• By the gram commands the highest per-unit price (the "convenience tax")
• Eighth typically costs 4-6x a single gram (i.e., 5-25% per-gram discount)
• Quarter typically costs 1.5-1.8x an eighth (i.e., additional 10-20% per-gram discount)
• Half typically costs 1.5-1.8x a quarter
• Ounce typically costs 1.5-1.8x a half

So an ounce often costs 6-10x what a single gram costs — a substantial bulk discount but not strictly proportional to weight.

In hemp-derived THCA markets, pricing structures generally follow similar logic, though the per-gram base prices tend to be lower than regulated marijuana markets because hemp products avoid the substantial state excise taxes.

Concentrates use different units

Cannabis concentrates — including THCA diamonds, live resin, distillate, rosin, and similar products — are typically sold in metric units without the eighth/quarter convention. Common sizes:

• Half-gram (0.5g) — common entry-size for concentrates
• 1 gram — most common single-purchase size
• 2 grams — bulk purchases
• 4 grams (or larger) — wholesale and bulk

Vape cartridges also use metric, typically 0.5g or 1.0g formats. Edibles are usually measured in milligrams of cannabinoid content per serving (e.g., "10 mg THC per gummy") rather than total product weight.

The fractional system is essentially flower-specific.

Legal limits and purchase caps

In jurisdictions where cannabis or hemp is regulated, purchase and possession limits often map to the standard weight increments:

• Recreational states typically allow possession of one ounce (28g) of flower for adult-use, with additional concentrate-specific limits
• Medical patients often have higher allowances
• Hemp markets generally don't impose purchase caps because hemp isn't a controlled substance under the framework — though specific states have their own rules

The one-ounce-of-flower standard for recreational possession in many states traces back to the same imperial measurement convention. It's a reasonable amount — enough for personal use, small enough that most people don't reasonably carry larger quantities — and the round number maps to the cultural standard.

Frequently asked questions