The shortest sūra to memorise is not the one with the fewest verses

Ask which sūra is shortest and almost every list answers by verse count: al-ʿAṣr, al-Kawthar and an-Naṣr, three āyāt each. It is the obvious measure and it is the wrong one, for the same reason counting verses misreports Juzʾ ʿAmma. An āyah is not a unit of size.

Measured by the Arabic text itself, the order changes:

Al-Ikhlāṣ has one more āyah than al-ʿAṣr and about a third less text. An-Nās has twice the verses of al-ʿAṣr and only ten more characters. Sort by verses and you get one ranking; sort by what you actually have to commit to memory and you get another.

How far the ruler is off

Across the whole muṣḥaf the gap is not subtle. Al-Baqara is 8.00% of the Arabic text. Al-Kawthar is 0.013%. That is a spread of about 615× between the largest sūra and the smallest — and a list that treats "a sūra" as a unit treats those two as one apiece.

The same is true inside a single āyah. 2:282, the verse on recording a debt, runs longer than several complete sūras at the end of the muṣḥaf.

What to do with it

If you are choosing what to memorise next, choose by text. The practical order for the shortest six is the table above, not the verse-count list — and the difference is real work: al-ʿAṣr is 65% more text than al-Kawthar despite both being "three verses".

None of which is an argument about merit. Al-Ikhlāṣ is not a lesser sūra for being short, and length is not why anyone memorises anything. It is only an argument about arithmetic: if a number is going to be put in front of someone, it should be counting the thing they are actually doing.