We are taught since grade school that there’s no point to mental math when a machine can do calculations faster and more accurately than our brains.
That might be true for the puny brains of your math teachers, but the GMAT doesn’t allow a calculator for the Quant section and using the included one is almost invariably still a massive waste of time on the GRE.
In short, even if you believe that the calculator is your greatest ally in math and feel adrift without it (GMAT) or that it’s necessary to use whenever possible (GRE), you are almost certainly hurting your performance.
GMAT and GRE questions are almost all intentionally designed to be solved without a calculator. These tests assess not only your mathematical ability, but also your problem-solving efficiency, logic, and strategic thinking.
Below, we explore five compelling reasons why using a calculator is more often a waste of time than a benefit on these exams.
One of the biggest misunderstandings about the GRE and GMAT is that they require raw number-crunching skills. In reality, the questions are crafted with mental strategies in mind.
You’ll rarely encounter complex decimals or irrational roots that require a calculator. Instead, you’ll see:
Test-makers know the calculator is available (only on certain GRE sections, and not at all on GMAT Quant), but they also know that savvy test-takers can beat the problem without punching numbers. The ability to simplify, recognize patterns, or apply proportional reasoning often leads to faster and more accurate solutions.
Example: A question might ask, “What is 49 x 51 – 1?” If you recognize the identity (a – 1)(a + 1) = a^2 – 1, you can solve it mentally as 50^2 – 1 = 2500 – 1 = 2499. No calculator needed.
When a calculator is in play, many students default to brute-force arithmetic. But this approach misses the point of standardized test math. You aren’t rewarded for your ability to calculate large numbers; you’re rewarded for recognizing shortcuts and logical patterns.
By instinctively reaching for the calculator, you may:
Moreover, overreliance on a calculator conditions your brain to focus on execution rather than strategy. You become a machine operator rather than a problem-solver, and the test punishes that mindset.
Calculators don’t make mistakes, but humans do—especially when typing on them under time pressure. Here are common calculator-related pitfalls:
Unlike math errors on paper, these are hard to spot because the calculator won’t warn you. If your logic is sound but your typing is off, your answer is wrong.
On the GMAT, you don’t even get a calculator on the Quant section, so relying on one during practice can set you up for bad habits. And on the GRE, the on-screen calculator is extremely basic (no parentheses, no order of operations handling), so even its utility is minimal.
Key Point: Speed and accuracy are vital. If using a calculator introduces friction, it’s a liability.
Time management is one of the most critical skills on both the GMAT and GRE. Every second counts, and calculators tend to slow students down for three reasons:
The best test-takers skip the calculator altogether for 90+% of the questions. They reserve it for only those where mental math truly becomes cumbersome or verification is needed, particularly when the question asks for a response in decimal form.
GRE Tip: Use the calculator to check division of decimals you don’t recognize—not for basic operations. Same goes for GMAT Data Insights.
Standardized test success isn’t just about solving problems. It’s about solving them fast and with confidence. Developing comfort with numbers—especially fractions, percentages, ratios, and squares—makes you far more competitive than any calculator can.
Using a calculator too often in practice deprives you of this agility. Instead of internalizing multiplication patterns or divisibility rules, your brain becomes passive. You memorize buttons, not numbers.
Building number sense helps you:
This kind of agility is what gets you through medium and hard questions on time. Calculators simply don’t teach it.
Pro tip: Practice drills in estimation, mental math, and number properties. You’ll feel the difference within weeks.
People with math skills that need strengthening often believe that because they are weak with mental calculation, or nervous about their math skills in general, that whatever the calculator says is correct.
This is a bit like “the internet says it’s true” or “AI says it’s true.” Maybe, but there’s a high chance that it’s not true. You need to be very clear about what you’re typing into the calculator and why you’re doing so.
If you can’t keep track of the calculation in some form–usually estimation–and have a good idea of where in your working you are, then use of the calculator can actually confuse your position within the workings.
Remember point 3 above: just because you type it in doesn’t make it correct. One of the first precepts in computer science comes in here: garbage in, garbage out. If you type something incorrectly or you do your reasoning incorrectly, the blunt tool of the calculator will only address its input.
If you fucked something up, then it’s not any more believable because the calculator screen says it.
Pro tip: It’s better policy not to fuck up in the first place.
On the GRE Quant section, the calculator is a tool of last resort, not your primary method. Think of it like a dictionary when writing an essay: useful for checking, but not for creating. The GMAT makes this philosophy even more obvious by eliminating the calculator altogether.
The best students build a toolkit of strategies:
When these techniques are well-practiced, a calculator becomes nearly irrelevant. Using a calculator is a waste of time and sucks. Don’t do it.
It’s easy to fall into the trap of thinking calculators are your secret weapon. But on the GMAT and GRE, they can slow you down, dull your skills, and even introduce errors. These exams are designed to be solved with brainpower, not buttons.
So the next time you’re tempted to reach for that calculator, stop and ask:
More often than not, you’ll find there’s a quicker path—and it starts in your head.
Friends don’t let friends use calculators. Because the calculator is a waste of time in basically every possible circumstance you’d ever find even on tests that allow it such as GRE Quant or GMAT Data Insights.
Train your number sense, not your calculator reflexes.
On test day, it could mean the difference between a good score and a great one.
How to Detect Baloney in GMAT Critical Reasoning When tackling Critical Reasoning questions on the…
2^(1/2)/4 + 3/(2*2^(1/2)) or \sqrt{2}\4 [latexpage] $\frac{\sqrt{2}}{4} + \frac{3}{2\sqrt{2}} = $ (The most difficult thing…
If x<8/5, which of the following could be greater than 1? That is, If $x…
The owner of an apartment purchased 1 window screen, 1 door handle, and 1 ceiling…
If y is the average (arithmetic mean) of 15 consecutive positive integers, which of the…
Top MBA Applicants: Consider European and UK Schools Over US Options in 2025 “Abandoning science…