Use basic linux command-line utility to calculate real disk capacity.
Print real disk capacity for 32G hard disk.
$ numfmt --from=si --to=iec --format="%.1f" --round=down 32G 29.8G
Print real disk capacity for 64G hard disk.
$ numfmt --from=si --to=iec --format="%.1f" --round=down 64G 59.6G
Print real disk capacity for 128G hard disk.
$ numfmt --from=si --to=iec --format="%.1f" --round=down 128G 119.2G
Print real disk capacity for 256G hard disk.
$ numfmt --from=si --to=iec --format="%.1f" --round=down 256G 238.4G
Print real disk capacity for 512G hard disk.
$ numfmt --from=si --to=iec --format="%.1f" --round=down 512G 476.8G
Print real disk capacity for 768G hard disk.
$ numfmt --from=si --to=iec --format="%.1f" --round=down 768G 715.2G
Print real disk capacity for 1T hard disk.
$ numfmt --from=si --to=iec --format="%.1f" --round=down 1T 931.3G
Print real disk capacity for 2T hard disk.
$ numfmt --from=si --to=iec --format="%.1f" --round=down 2T 1.8T
Print real disk capacity for 4T hard disk.
$ numfmt --from=si --to=iec --format="%.1f" --round=down 4T 3.6T
Print real disk capacity for 5T hard disk.
$ numfmt --from=si --to=iec --format="%.1f" --round=down 5T 4.5T
Print real disk capacity for 6T hard disk.
$ numfmt --from=si --to=iec --format="%.1f" --round=down 6T 5.4T
Print real disk capacity for 8T hard disk.
$ numfmt --from=si --to=iec --format="%.1f" --round=down 8T 7.2T
Print real disk capacity for 10T hard disk.
$ numfmt --from=si --to=iec --format="%.1f" --round=down 10T 9.0T