Math Calculators
Welcome to CalcDune’s free online math calculators. Whether you need a quick percentage, a tricky fraction, or the area of a circle, our tools give you instant results — no sign-up, no download, no fees. Every calculator shows the formula and the calculation steps, so you don’t just get the answer, you understand how it was found. Works on desktop, tablet, and mobile.
44 free calculators
Algebra
Applied & Science
Basic Arithmetic
Basic Calculator
A simple two-number calculator for addition, subtraction, multiplication, division and exponents.
Use calculator →Big Number Calculator
Add, subtract, multiply or divide very large whole numbers with full precision.
Use calculator →Exponent Calculator
Raise a base to any power, including negative or fractional exponents.
Use calculator →Fraction Calculator
Add, subtract, multiply or divide two fractions and simplify the result.
Use calculator →Long Division Calculator
Divide two numbers and see the quotient, remainder and decimal result.
Use calculator →Percent Error Calculator
Calculate the percent error between an experimental and theoretical value.
Use calculator →Percentage Calculator
Find a percentage of a number, what percent one number is of another, or percent change.
Use calculator →Ratio Calculator
Simplify a ratio, or scale it to find an equivalent value.
Use calculator →Root Calculator
Calculate the nth root of a number (square root, cube root, or any root).
Use calculator →Rounding Calculator
Round a number to a chosen number of decimal places, or round up/down.
Use calculator →Scientific Calculator
Evaluate expressions with +, -, *, /, ^, parentheses and functions like sqrt, sin, cos, tan, log, ln.
Use calculator →Scientific Notation Calculator
Convert a number to and from scientific notation.
Use calculator →Geometry
Area Calculator
Calculate the area of a square, rectangle, triangle, circle, trapezoid or parallelogram.
Use calculator →Circle Calculator
Enter any one property of a circle (radius, diameter, circumference or area) to find the rest.
Use calculator →Distance Calculator
Find the straight-line distance between two points on a plane.
Use calculator →Pythagorean Theorem Calculator
Find a missing side of a right triangle using a^2 + b^2 = c^2.
Use calculator →Right Triangle Calculator
Solve a right triangle's missing side, angles and area from two known sides.
Use calculator →Surface Area Calculator
Calculate the total surface area of a cube, box, sphere, cylinder or cone.
Use calculator →Triangle Calculator
Enter three side lengths to get the area, perimeter, angles and triangle type.
Use calculator →Volume Calculator
Calculate the volume of a cube, box, sphere, cylinder, cone or square pyramid.
Use calculator →Number Theory
Binary Calculator
Convert between decimal and binary numbers.
Use calculator →Common Factor Calculator
List all factors shared by two numbers.
Use calculator →Factor Calculator
List every factor of a whole number.
Use calculator →Greatest Common Factor Calculator
Find the greatest common factor (GCF / GCD) of two or more numbers.
Use calculator →Hex Calculator
Convert between decimal and hexadecimal numbers.
Use calculator →Least Common Multiple Calculator
Find the least common multiple (LCM) of two or more numbers.
Use calculator →Log Calculator
Calculate the logarithm of a number in base 10, base 2, natural log, or a custom base.
Use calculator →Number Sequence Calculator
Generate an arithmetic, geometric or Fibonacci-style sequence and find the sum.
Use calculator →Prime Factorization Calculator
Break a number down into its prime factors.
Use calculator →Statistics & Probability
Average Calculator
Find the average (mean) of a list of numbers.
Use calculator →Confidence Interval Calculator
Calculate a confidence interval for a sample mean.
Use calculator →Mean, Median, Mode, Range Calculator
Quickly find the mean, median, mode and range of a data set.
Use calculator →P-value Calculator
Calculate the p-value for a given z-score and test type.
Use calculator →Permutation and Combination Calculator
Calculate the number of permutations (nPr) or combinations (nCr).
Use calculator →Probability Calculator
Calculate the combined probability of two events (AND / OR).
Use calculator →Random Number Generator
Generate one or more random numbers within a range.
Use calculator →Sample Size Calculator
Estimate the sample size needed for a survey given confidence level and margin of error.
Use calculator →Standard Deviation Calculator
Calculate mean, variance and standard deviation for a set of numbers.
Use calculator →Statistics Calculator
Get a full statistical summary (mean, median, mode, range, variance, std dev) for a data set.
Use calculator →Z-score Calculator
Find the z-score for a value given the mean and standard deviation of a distribution.
Use calculator →Complete Guide to Math Calculators
From quick answers to step-by-step learning — make the most of every tool.
How to Use Our Math Calculators
Every calculator on this page runs directly in your browser — there's nothing to install and no account to create. Simply choose the tool you need, enter your numbers, and the result appears instantly as you type.Unlike most calculator sites, CalcDune shows you the formula and each step of the calculation. That makes these tools just as useful for learning as they are for quick answers: students can check their homework method, and professionals can verify figures before using them in a report or budget.
All calculators are free for unlimited use and work on any device — phone, tablet, or computer. Results update live, so you can adjust your inputs and see how the answer changes in real time.Looking for a calculator we don't have yet?
Contact us — we add new tools based on visitor requests.
Math Calculator FAQs
Are these math calculators really free?
Yes — every calculator on this page is 100% free with no limits, no sign-up, and no hidden fees. You can use them as many times as you like.Do I need to create an account or download anything?
No. All calculators run directly in your web browser. Just open the page, enter your numbers, and get your answer — nothing to install and no personal information required.Do the calculators show the formula and steps?
Yes. Every result includes the formula used and a step-by-step breakdown of the calculation, so you can verify the answer or learn the method.Can I use these calculators on my phone?
Absolutely. The page and every calculator are fully responsive and designed to work smoothly on phones, tablets, and desktop computers.What should I do if a calculator gives an unexpected result?
Double-check that your inputs are in the correct fields and units — for example, radius vs. diameter in the circle calculator. If something still looks wrong, please contact us so we can fix it.
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