Blank CD and DVD capacity

Standard Nominal Capacity True Capacity (bytes) True Capacity (megabytes) True Capacity (gigabytes)
CD-ROM 650 MB 681984000 650.3 0.6351
700 MB 737280000 703.1 0.6866
90 minutes 829440000 791.0 0.7725
99 minutes 912384000 870.1 0.8497
DVD-5 4.7 GB 4700372992 4483 4.377
DVD-9 8.5 GB 8547993600 8152 7.95

Sources: Wikipedia: CD-ROM, Wikipedia: DVD-ROM, SSS – File Storage & Management