What is a 120 mm optical disc?

A 120 mm optical disc is a standard-sized circular disc used to store digital data via laser-readable pits and lands. It is the most common size for optical media such as CDs, DVDs, and Blu-ray Discs and is widely used in data distribution and archival.

How is data stored on a 120 mm optical disc?

Data is encoded as microscopic pits and lands on the disc’s surface. A low-power laser in an optical disc drive reads these features by detecting variations in reflected light, which are interpreted as binary data.

What are the key features of a 120 mm optical disc?

This disc format is flat, circular, and typically made of polycarbonate with a reflective metallic layer. It is the most common physical form for distributing and archiving large volumes of data in digital media.

Is the 120 mm optical disc the only size available?

No, while 120 mm is the standard size, an 80 mm "mini" version also exists for portable and compact devices.

What are the typical capacities for 120 mm optical discs?

Standard capacities include 700 MB for CDs, 4.7 GB for single-layer DVDs, and 25 GB for single-layer Blu-ray Discs. Specialized archival versions like M-Disc and Archival Disc are also 120 mm and offer extended data lifespans.

What is the historical significance of the 120 mm optical disc?

It has been the standard for data storage in formats like CD, DVD, and Blu-ray since the late 1970s. It enabled the mass production of software, music, and video media and remains essential for long-term archival.

120 mm optical disc

most common optical disc form factor

Class type of: optical disc Q104387898

Facts

3 properties

Instance of: form factor
Subclass of: optical disc^[2]
Diameter: 120 millimetre^[3]

🏷️ Also known as

en 120 mm disc en 120 mm optical disc en 120mm optical disc en 12 cm disc en 12 cm optical disc

🔖 Identifiers · 1

Image (Wikimedia Commons): DVDs-12cm-8cm.jpg ↗

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🔗 Connections

Instance of 1

form factor

Subclass of 1

optical disc

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Category:120 mm discs

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Summary

120 mm optical disc is a form factor^[1].

References

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Direct Wikidata claims

Class ancestry

[1] ↑ 120 mm optical disc is an instance of form factor (Q1148887) [P31, primary]. Wikidata. wikidata.org.

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@misc{4ortxyz_120-mm-optical-disc_2026, author = {{4ort.xyz Knowledge Graph}}, title = {{120 mm optical disc}}, year = {2026}, url = {https://4ort.xyz/entity/120-mm-optical-disc}, note = {Accessed: 2026-03-18}}

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