Azure virtual machine billing is somewhat arcane, unfortunately.

For reasons unknown, Microsoft’s engineers decided all virtual machine usage should be billed as an “A1” virtual machine, with hours adjusted to make the actual charges match public pricing for other virtual machine sizes.

For example, an A2 instance has double the resources of an A1 instance, so each hour of usage is billed as two hours of A1 instance usage.

Conversion factors for various instance sizes are in the tables below.

And yes, you’re right, this is an absolutely insane way to handle billing.

Windows

Non-Windows