So "megabytes" appears to be the power-of-ten unit, which is generally not that helpful in practice.

   ≫ 6 megabytes to bytes
     6 MB -> B
      = 6000000 B

Assuming you're sticking with the power-of-ten unit, that means you should really grow support for the (sigh) "mebibytes" family of units; i.e., what some folks are retro-actively calling the power-of-two byte unit.

   ≫ 6 mebibytes to bytes
     6 × mebibytes -> B
     Unknown identifier: mebibytes