Why 750 on Security+ Is Not 83 Percent
The SY0-701 passing score of 750 sits on a 100 to 900 scale that does not start at zero and is not a percentage. Here is what the number actually measures.
Everyone studying for SY0-701 learns the passing score early: 750. Almost everyone then does the same math on it. 750 out of 900 is 83 percent, so I need 83 percent of the questions right.
That figure is wrong, and it is wrong in the expensive direction, because it sets a bar higher than the exam asks for and then makes every practice result look like a countdown to a mark that was never there.
The scale does not start at zero
The CompTIA Security+ scaled score runs from 100 to 900. Almost everybody skims it. One hundred is the floor.
There is your broken percentage. That is the whole issue. You could walk in and answer nothing at all, and you would still not score 0, since the bottom of the range is 100. The distance a candidate travels is 800 points wide, then, and the passing mark of 750 sits 650 points up that run.
Dividing 750 by 900 treats the bottom of the scale as an origin, which it is not. Out comes a number with nothing attached to it.
Scaled is not raw wearing a different hat
Now the deeper problem, and it is the one that actually matters if you want your practice numbers to mean anything at all. A scaled score converts your raw performance rather than reporting it, and that conversion is the whole point.
CompTIA maintains multiple forms of the exam. Two people sitting SY0-701 in the same week can face different question sets, and those sets cannot be identical in difficulty however carefully they are assembled. A raw count would mean different things depending on which form you drew. Scaling exists in order to strip that unfairness out, so a harder form needs fewer correct answers to reach 750 than an easier one does.
Which brings up the annoying part. CompTIA does not publish the conversion. No table. No fixed count.
What about that figure you have seen quoted, the one that says 68 questions, passed around study groups and forum threads as though somebody somewhere had checked it? Someone guessed it, or it held true for a single form on a single day.
What this does to your practice scores
The bad arithmetic does real damage here. Watch how.
Believe that 750 means 83 percent and you will read an 80 percent practice result as a failure, then keep drilling until the number moves. Your practice percentage and the exam's scaled score are not the same unit, though; they are not even measured against the same pool of questions. Comparing them is a bit like checking whether your weight in kilograms clears your height in inches.
The exam is up to 90 questions in 90 minutes, mixing multiple choice with performance based. A 50-question multiple choice set from some vendor does tell you something real. What it tells you is how your recall is doing on that vendor's questions, which is not your position relative to 750.
So what deserves your attention instead? Two readings beat the headline percentage, and a third thing is worth checking separately.
Consistency across domains matters more than the average does. A flat 78 percent across all five domains is a far stronger position than an 85 built out of 95 in Domain 1 and 60 in Domain 4. The exam weights its domains, and it will find the weak one. The published objective list shows how the weighting falls.
Being able to explain the wrong answer matters more than getting it right. A lucky guess and real knowledge produce identical marks on a practice test, though they produce very different outcomes on an exam that phrases things a little differently.
Then, separately: PBQs. Which format do people prepare for least? That one, and a multiple choice percentage says nothing whatsoever about it. There is a free one here if you have not tried the format.
Where that leaves the number
750 is a scaled score on a 100 to 900 range. It does not convert into a percentage, and the count of questions behind it is unpublished and varies by form.
So drop it. Really. Aim instead at knowing all five domains well enough that the form you happen to draw stops being a factor in how your day goes.