# Ounce

> An ounce of cannabis is 28.35 grams, rounded to 28 g in retail; slang includes zip, O and onion.

- Canonical: https://genetixbay.com/knowledge/glossary/ounce.html
- Also written: oz, zip, an O, onion, zips
- Glossary category: Grower slang and culture
- Status: Draft: awaiting expert review · Updated: 2026-10-31
- Licence: CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0/), attribute "GenetixBay cannabis glossary"

An ounce (oz) is 28.35 g (avoirdupois), rounded to 28 g when cannabis is sold. Slang names include "zip" (from zip-lock bags), "O" and "onion".

## In practice

Many personal possession limits are written in ounces or in grams close to an ounce, for example 30 g in some places and 1 oz in others. The exact limit, and whether it covers dried flower only or equivalents, depends on the jurisdiction; check local rules.

For yield, growers often talk in ounces per plant or per light. "Two zips off one plant" means about 56 g dry.

## Units and formula

| Slang | Nominal weight | Metric |
|---|---|---|
| Gram | 1 g | 1 g |
| Eighth | 1/8 oz | 3.5 g (exact: 3.54 g) |
| Quarter | 1/4 oz | 7 g |
| Half | 1/2 oz | 14 g |
| Ounce (zip, O) | 1 oz | 28 g (exact: 28.35 g) |
| QP | 1/4 lb (4 oz) | 113 g |
| Pound (elbow, LB) | 1 lb (16 oz) | 454 g (exact: 453.6 g) |

Retail rounds an eighth to 3.5 g and an ounce to 28 g.

## Don't confuse with

- **Troy ounce**: 31.1 g, used for precious metals, not cannabis.
- **Fluid ounce**: a volume, not a weight.

## Related terms

[Gram](https://genetixbay.com/knowledge/glossary/gram.md), [Eighth](https://genetixbay.com/knowledge/glossary/eighth.md), [QP](https://genetixbay.com/knowledge/glossary/qp.md), [Elbow](https://genetixbay.com/knowledge/glossary/elbow.md), [Possession limit](https://genetixbay.com/knowledge/glossary/possession-limit.md)