CIDR Trainer trains users to perform network subnet calculations. It uses directed training drills while providing documentation to instruct users to perform each step of network subnetting calculations.
CIDR Trainer includes IPv4 and IPv6 CIDR calculators.
Version 1.1 includes the following categories of drills:
1-digit hexadecimal and binary drills
2-digit hexadecimal and binary drills
IPv4 terminology drills
IPv4 prefix-length drills
IPv4 CIDR drills
IPv6 Address Shortening and Lengthening Drills
IPv6 Terminology Drills
IPv6 CIDR Drills
IPv4 and IPv6 CIDR Calculators
You may try each training drill for free 20 times. After that you may try the other drills or purchase a permanent unlock of all training drills for a low price (see in-app purchases for the "forever full-unlock" price in your region). One purchase unlocks all versions of the app (iOS, iPadOS, and MacOS). CIDR Trainer uses iCloud to sync drill progress between your devices.
Each training drill has a "help" button in the top-right which provides related documentation
Full list of drills: (you may try them in any order)
IPv4 prefix-length to binary netmask
IPv4 binary netmask to prefix-length
IPv4 prefix-length to hexadecimal netmask
IPv4 hexadecimal netmask to prefix-length
IPv4 prefix-length to dotted-decimal netmask
IPv4 dotted-decimal netmask to prefix-length
IPv4 CIDR Drills:
Number of IPs in a CIDR
Number of usable unicast IPs in a CIDR
CIDR to network address in binary
CIDR to network address in decimal
Well-formed CIDR to broadcast address
Well-formed CIDR to first usable IP address
Well-formed CIDR to last usable IP address
Fixed a bug that could cause a crash in IPv4 address type drill
Fixed an error in the IPv6 address lengthening drill for :: and ::1 cases
Several cosmetic fixes
Changed iOS support to start at 15.0 instead of 15.2
1.1
2022-02-27
Major update adding a large number of IPv6 drills
Added IPv4/IPv6 CIDR Calculators
Fixed a bug related to iCloud sync of progress
1.0
2022-02-20
Cheat Codes for In-App Purchases
Item
Price
iPhone/iPad
Android
Full Unlock (Unlocks all CIDR Trainer features forever)