What are the differences between DVD5 and DVD9?

The main difference between DVD5 and DVD9 is the capacity. DVD9 has more space than DVD5's. DVD ± R DL discs are called DVD9. The single-sided double-layer DVD discs can store data up to 8.5GB. Those single-sided single-layer DVD discs can save data  up to 4.7GB. They are called DVD5.

1) The DVD5 discs are single-sided single-layer discs. DVD5 can store accurately 4,700,000,000 bytes and that is 4.37 GB on computer where 1 kbyte is 1024 bytes. A DVD5 disc can generally store a 120-min DVD movie.

2) The DVD9 discs are usually referred to single-side dual-layer discs. DVD9 store accurately 8,540,000,000 bytes and that is 7.95 GB on computer. A DVD9 disc can store a 240-min DVD movie.

To view the capacity of commercial DVDs, insert your DVD disc into your Mac's DVD drive. When the DVD icon appears on desktop, hold Control key and click the DVD icon. Then select Get Info option to view its capacity. If the capacity is less than 4.7 GB, it is a DVD5 disc. If the capacity is larger than 4.7GB but smaller than 8.5GB, it's a DVD9 disc.