# Tempered vs Annealed Glass: What's the Difference?

Tempered glass is about four to five times stronger than annealed glass and breaks into small fragments. Annealed glass can still be cut. Here is how to choose.

Source: https://www.temperededge.com/guides/tempered-vs-annealed-glass/

**Annealed glass** (also called float glass) is standard glass that has been slowly cooled during manufacturing to relieve internal stresses. It can be cut, drilled and edged after fabrication. When it breaks, it forms long, sharp shards that can cause injury.

**Tempered glass** is annealed glass that has been heat-treated in a tempering furnace to create surface compression. It is 4–5 times stronger than annealed glass and, when broken, fractures into small, relatively harmless fragments (the "dice" pattern).

Key differences:

- **Strength:** Tempered is 4–5x stronger than annealed of the same thickness

- **Post-fabrication:** Annealed can be cut and drilled after purchase; tempered cannot

- **Break pattern:** Annealed creates dangerous shards; tempered creates small safe fragments

- **Code requirements:** Most building codes require tempered glass in hazardous locations (doors, showers, sidelites, near stairs)

- **Cost:** Tempered costs more per square foot due to the heat-treatment process

**Which should you use?** Code calls for tempered glass in a door, within 24" of a door, in a shower, or near the floor in a path people walk. Picture frames, occasional tables out of the way, and anything you may still need to cut can stay annealed. If you are unsure, use tempered.

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