CD/DVD disc Size & Weight

A standard CD, DVD, and Blu-ray disc are all 120 mm (4.7 in) in diameter and 1.2 mm thick, with a 15 mm centre hole. A bare disc weighs about 15 to 20 grams. The size was fixed by the “Red Book” CD standard in 1980 and every optical disc format has kept it.

This guide covers the exact CD dimensions, the smaller “mini CD” size, why all optical discs share one diameter, and how a CD compares to a vinyl record and a drinks coaster.

Quick Answer: How Big Is a CD?

A standard CD is 120 mm across, 1.2 mm thick, with a 15 mm hole, weighing 15 – 20 g. The data area runs from a 46 mm inner diameter to a 116 mm outer diameter. Mini CDs are 80 mm across and hold about 210 MB.

CD Dimensions at a Glance

• Diameter: 120 mm (standard); 80 mm (mini CD / CD single)
• Thickness: 1.2 mm, the same for CD, DVD, HD DVD, and Blu-ray
• Centre hole: 15 mm, sized to the spindle clamp
• Clamping area: 26 – 33 mm diameter ring around the hole, no data
• Lead-in / lead-out: unrecorded rings at the inner and outer edges

What Does a CD Look Like in Size?

A CD is a little smaller than a standard drinks coaster and about the size of a small saucer. Its 120 mm diameter is close to the short side of a CD jewel case (which is 142 x 125 mm). Stacked, about 21 bare discs make 25 mm; on a spindle, 100 discs stand roughly 120 mm tall including the hub.

6 Everyday Comparisons for a CD

1. A 12-inch vinyl record (300 mm) is 2.5 times a CD’s diameter.
2. A drinks coaster (~95 – 100 mm) is a bit smaller than a CD.
3. A CD jewel case (142 x 125 mm) is just larger than the disc in both directions.
4. A tea saucer (~140 mm) is slightly larger.
5. A DVD is exactly the same 120 mm size as a CD.
6. An adult palm (~100 mm across) is a little smaller than a CD.

CD Size in Different Units

Why Every Optical Disc Is 120 mm

The CD’s 120 mm size is often said to have been chosen so a disc could hold about 74 minutes of audio, enough for Beethoven’s Ninth Symphony. Whatever the exact reason, once the size was set, keeping it meant DVD, HD DVD, and Blu-ray players could share the same trays, spindles, and manufacturing lines. So a Blu-ray disc holds about 50 GB in the same 120 x 1.2 mm shape that a CD uses for 700 MB, purely through a finer laser and tighter tracks.

Common Mistakes When Comparing CD Dimensions

1. Thinking a DVD is bigger than a CD. They are identical in size; only the storage differs.
2. Confusing the disc and the case. The jewel case is 142 x 125 x 10 mm; the disc is 120 mm across.
3. Assuming the whole disc holds data. The inner ~46 mm and the outer edge are unrecorded.
4. Forgetting mini discs exist. The 80 mm CD single and 80 mm mini DVD use the same tray with a smaller recess.
5. Quoting one weight. A bare disc is ~16 g; a disc plus a slim case is closer to 60 g.

Frequently Asked Questions

What is the diameter of a CD?

120 mm (4.72 in).

How thick is a CD?

1.2 mm.

How big is the hole in the middle of a CD?

15 mm across.

Is a DVD the same size as a CD?

Yes, exactly: 120 mm diameter, 1.2 mm thick.

How much does a CD weigh?

About 15 – 20 g for a bare disc.

What is a mini CD?

An 80 mm disc, used for CD singles and small software, holding around 210 MB.

Final Takeaway

A CD, DVD, and Blu-ray disc are all 120 mm across, 1.2 mm thick, with a 15 mm centre hole, weighing about 16 grams bare. The size has not changed since 1980, which is why one drive can read every optical format, and mini discs are the only common exception at 80 mm.