Understanding CD DVD and USB Flash Drive Capacity in Bytes, KB, MB, and GB

CD DVD and USB Flash Drive Capacity

Comparison chart showing common capacity for CD/DVD and USB flash drives.

It's important to know the actual data size capacity for CD/DVD or USB flash drives. Some of the documentation is confusing because the metric system is 10 based and a KiloMeter sounds a lot like a KiloByte but a KiloMeter is 1000 meters, while a KiloByte is 1024 bytes.

To make matters worse, sometimes product documentation, marketing material, or specifications may refer to Gigabytes (GB) or Megabytes (MB) but you're not sure if they got to those values using metric 1000 based conversions or the proper 1024 computer binary based conversions (2,4,8,16,32,64,128,256,512,1024). For example, DVD-R is often said to have a capacity of 4.7 GB but it really only has a capacity of 4.377 GB (4,700,000,000 bytes).

The following table explains the actual data capacity of the some common CD/DVD and USB Flash Drive sizes. Some of the USB flash drive information may vary depending on the chip manufacturer of the USB thumb drive, and whether it's formatted FAT32, NTFS etc.

Custom USB Flash Drives on demand at order time. Custom USB Flash Drives on demand at order time.
Product Bytes KB (Bytes / 1024) MB (KB / 1024) GB (MB / 1024)
CD-R 737,280,000 720,000 703 0.687
DVD-5 (single layer) 4,700,000,000 4,589,843 4,482 4.377
DVD-9 (dual layer) * see below 8,500,000,000 8,300,781 8,106 7.92
USB 512MB 504,078,336 492,264 480 0.467
USB 4GB 4,018,593,792 3,924,408 3,832 3.74
USB 8GB 8,036,294,656 7,847,944 7,664 7.48
USB 16GB 15,633,997,000 15,267,575 14,909 14.56
* TrepStar does not offer dual layer. Even the best blank dual layer media (as of this writing 3/12/23) often fails during the burn of dual layer discs. Our research shows that up to 20% of the burns are bad, and a fair percentage of DVD players are incompatible with even the best burned dual layer discs. This is why we do not offer them. It would cause too many support issues and costs for us, as well as refund requests from your customers. We suggest you re-author your DVD into two discs, or use compression software to fit your larger source DVD onto the single layer DVD-5 (4.7GB) DVDs that we offer. You might want to purchase 1Click DVD Copy PRO. We do not receive any affiliate commission or money from 1Click. We've worked with them before and we trust their software and their company.

USB capacity.  Flash Drive Packaging Prices.