Subnetting Speed Test
Subnetting is the one topic where speed genuinely matters: in an exam, on a call, or halfway up a ladder. Pick a length, pick a difficulty, and see how many you can get right in a minute.
This drill needs JavaScript. The questions are generated in your browser: nothing is sent anywhere.
How the score works
Your net score is correct answers per minute. Speed on its own rewards guessing, so accuracy is applied to it:
Speed × Accuracy = Net. Answer 18 questions a minute with 88% of them right and you score 16 net CPM. The multiplication is not a weighting anyone invented: answers per minute multiplied by the share that were correct is correct answers per minute. It always checks out.
Slow answers mean the method, not the speed
If the clock is the problem, the fix is usually the technique rather than practice. Read Subnetting for the block-size method, then come back. The Subnet Calculator works the same maths this drill grades you against.