Dropping Calculator for Physics: Should You?

Updated 12 November 2026 · Standard formula, shown below

Average speed 10.00 m/s

Time: 10 s; You entered
Distance: 100 m; You entered

Dropping your calculator for physics class is usually a bad idea, but the real question is which calculator to use and when. You still need a calculator for exams and homework, but the type matters—and for many physics problems, a scientific calculator is enough, while a graphing calculator is optional.

Formula

Average speed is distance divided by time:

v = d / t

v = average speed (m/s)
d = distance traveled (m)
t = time taken (s)

This is the simplest form of the speed formula, often the first one taught in physics. For constant velocity, it’s exact. For changing velocity, it gives the average over the whole trip.

Worked Example

Using the default values from the calculator: distance = 100 m, time = 10 s.

Write the formula: v = d / t
Plug in the numbers: v = 100 / 10
Divide: v = 10 m/s

The calculator shows 10.00 m/s, matching the hand calculation.

Why You Still Need a Calculator

Physics is math applied to the real world. Even if you’re great at mental math, problems often involve square roots, trig functions, logarithms, and large or tiny numbers (like 6.67 × 10⁻¹¹). A calculator prevents arithmetic errors and speeds up problem solving, especially during timed exams.

Many physics courses allow scientific calculators but restrict graphing ones on tests. Some exams (like the AP Physics exams) have specific calculator policies—check your course syllabus or exam guidelines.

Scientific vs. Graphing: Which Do You Need?

For most introductory physics (mechanics, electricity, waves), a scientific calculator is sufficient. It handles trig, logs, exponents, and scientific notation. Graphing calculators are useful for plotting functions, solving systems, and doing statistical analysis—but those are rarely required in algebra-based physics. In calculus-based physics, you might use a graphing calculator for integrals or derivatives, but many students manage with a scientific one plus a computer.

If you already own a graphing calculator (like a TI-84), use it. If you’re buying new, a scientific model (like TI-36X Pro or Casio fx-115) is cheaper and often allowed where graphing is not.

Common Mistakes When Using a Calculator in Physics

Unit mix-ups: Always convert to SI units before calculating. For example, km to m, hours to seconds.
Radians vs. degrees: Trig functions in physics usually use radians. Check your calculator mode.
Order of operations: Use parentheses for denominators. For example, 1/(2π√(LC)) is not the same as 1/2π√(LC).
Rounding too early: Keep extra digits until the final answer, then round to the correct significant figures.
Copying errors: Re-read the problem and the display before writing the answer.

What to Do If You Forget Your Calculator

If you forget your calculator on exam day, ask the instructor if you can borrow one. Many schools have spares. If you’re at home, use a free online calculator or a phone app, but be aware that phones are usually not allowed in exams. For practice, use the calculator on your computer or a physical one you can borrow from a friend.

Alternatives to a Physical Calculator

Online calculators and phone apps can handle most physics math. For quick conversions or simple formulas, this site’s calculator works. For more complex problems, a scientific calculator app like RealCalc or a graphing app like Desmos (on a phone or computer) can help. However, during exams, you’ll likely need a physical calculator that meets your school’s rules.

Frequently Asked Questions

Can I use a graphing calculator on the AP Physics exam?

Yes, the AP Physics exams allow graphing calculators, but they must have no internet capability. Check the College Board’s current calculator policy for the exact list of permitted models.

Is a scientific calculator enough for college physics?

For most algebra-based and calculus-based physics courses, yes. You’ll rarely need graphing features, but if you’re unsure, ask your professor or check the course syllabus.

Why does my physics teacher say to put the calculator away?

Sometimes teachers want you to practice estimation and unit analysis without a calculator, especially for conceptual questions. But for numeric problem-solving, they usually expect you to use one.

What does “dropping” a calculator mean?

In this context, “dropping” means stopping using a calculator altogether. It’s rarely a good idea for physics, because most problems require precise arithmetic.

Can I use a calculator on the MCAT or other medical entrance exams?

The MCAT does not allow calculators, but it provides on-screen tools for some sections. Check the official MCAT website for current rules. For other exams, always verify the policy.

How do I avoid calculator errors in physics?

Always write the formula, convert units to SI, use parentheses, and check your answer for reasonableness. Also, practice using your calculator’s functions (like sin, cos, log) before the exam.

Formula used

in t | Time | s | 10 | 0
in d | Distance | m | 100 | 0
out v | Average speed | m/s | d / t | 2

Each line is one input (in, sel, list) or one result (out: label, unit, formula, decimals). How the calculators work

Method: the standard formula for this calculation, rounded as each result states. See how the calculators work or report an error.