User CAL vs Device CAL — which one is cheaper?

The math is simple. Count how many users and how many devices will access the server. Whichever number is smaller is the SKU you want.

If 30 staff each have a laptop, a phone and a desktop (90 devices, 30 users), User CALs win — you buy 30 instead of 90. If 20 shift workers share 5 shop-floor terminals around the clock (5 devices, 20 users), Device CALs win — you buy 5 instead of 20. The CAL type is set per server role, so the Exchange Server and the Windows Server in the same rack can use different CAL types.

Still unsure?

Talk to a licensing specialist for a written, signed quote tailored to your environment.