Note that "df -h" treats 1G as 2^30 (i.e. 1024^3) bytes, whereas fdisk treats 1GB as 10^9 (i.e. 1000^3) bytes. Likewise, "df -h" treats 1M as 2^20 bytes and fdisk treats 1MB as 10^6 bytes. I create my partitions with GNU parted using the "unit GiB" option, so that my numbers are consistent.