Math & Science

Scientific, statistics, geometry, physics, and chemistry calculators.

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Percentage Calculator

Calculate percentages three ways: what is X% of Y, X is what % of Y, and percentage change from X to Y.

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Fraction Calculator

Add, subtract, multiply, and divide fractions. Results shown as fraction, mixed number, and decimal.

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Standard Deviation Calculator

Calculate mean, variance, and standard deviation (population and sample) from a data set.

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Probability Calculator

Calculate probability from favorable and total outcomes. Find combined probability for independent or mutually exclusive events.

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Triangle Calculator

Calculate all sides, angles, area, and perimeter of a triangle from any 3 known values.

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Area Calculator

Calculate area and perimeter for rectangles, circles, triangles, trapezoids, and ellipses.

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Volume Calculator

Calculate volume and surface area for cubes, boxes, cylinders, spheres, and cones.

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Speed Distance Time Calculator

Solve for speed, distance, or time from any two known values.

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Random Number Generator

Generate random numbers in a range with options for quantity, duplicates, and sorting.

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Quadratic Formula Calculator

Solve quadratic equations ax²+bx+c=0. Find roots, discriminant, and vertex.

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Slope Calculator

Calculate slope, y-intercept, line equation, distance, and midpoint from two points.

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Circle Calculator

Calculate radius, diameter, circumference, and area from any one circle measurement.

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Cylinder Volume Calculator

Calculate cylinder volume in cubic feet, gallons, and liters, plus surface area.

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Sphere Calculator

Calculate sphere volume, surface area, diameter, and circumference from radius.

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Exponent Calculator

Calculate any base raised to any power including negative and fractional exponents.

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Logarithm Calculator

Calculate logarithms in any base including natural (ln), common (log10), and binary (log2).

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Permutation & Combination Calculator

Calculate permutations P(n,r) and combinations C(n,r) with factorial breakdown.

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Matrix Calculator (2×2)

Calculate determinant, inverse, transpose, and multiplication for 2×2 matrices.

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GCD & LCM Calculator

Find greatest common divisor and least common multiple with prime factorization.

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Scientific Notation Calculator

Convert between standard form and scientific notation. Also shows engineering notation.

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Roman Numeral Converter

Convert between Arabic numbers (1-3999) and Roman numerals bidirectionally.

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Binary / Hex / Octal Converter

Convert numbers between decimal, binary, octal, and hexadecimal.

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Z-Score Calculator

Calculate z-score, percentile, and probability from a value, mean, and standard deviation.

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Confidence Interval Calculator

Calculate confidence interval bounds and margin of error at 90%, 95%, or 99% confidence.

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Sample Size Calculator

Calculate required sample size for surveys from population, confidence level, and margin of error.

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Chi-Square Calculator

Calculate chi-square statistic and p-value from a 2×2 contingency table.

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Correlation Calculator

Calculate Pearson correlation coefficient (r) and r² from two data sets.

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Molarity Calculator

Calculate molarity from moles and volume. Also solve for moles or volume.

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Molecular Weight Calculator

Calculate molecular weight from chemical formula. Parses element symbols and subscripts.

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Half-Life Calculator

Calculate remaining amount after radioactive or chemical decay over time.

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Ohm's Law Calculator

Solve for voltage, current, or resistance from any two values. Also shows power (watts).

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ANOVA Calculator

Perform one-way ANOVA analysis of variance with F-statistic and p-value.

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Density Calculator

Calculate density, mass, or volume from the other two values.

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Distance Between Points Calculator

Calculate the distance between two points in 2D or 3D space.

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Energy Calculator

Calculate kinetic, potential, or total energy from mass, velocity, and height.

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Force Calculator

Calculate force, mass, or acceleration using Newton's second law F=ma.

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Mean, Median & Mode Calculator

Calculate mean, median, mode, and range from a set of numbers.

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Midpoint Calculator

Find the midpoint between two points in 2D or 3D space.

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Molecular Weight Calculator

Look up molecular weight and properties of common chemical compounds.

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P-Value Calculator

Calculate p-value from test statistic and distribution type.

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Percent Error Calculator

Calculate percent error between experimental and theoretical values.

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Percentage Change Calculator

Calculate percentage increase or decrease between two values.

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Prime Factorization Calculator

Find the prime factorization of any positive integer.

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Proportion Calculator

Solve proportions and find the missing value in a ratio equation.

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Pythagorean Theorem Calculator

Calculate the missing side of a right triangle using the Pythagorean theorem.

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Ratio Calculator

Simplify ratios, scale ratios, and solve ratio problems.

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Regression Calculator

Perform linear regression analysis with slope, intercept, and R-squared.

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Significant Figures Calculator

Count significant figures and round numbers to specified sig figs.

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Square Root Calculator

Calculate square root, cube root, and nth root of any number.

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Surface Area Calculator

Calculate surface area of common 3D shapes including sphere, cylinder, and cone.

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T-Test Calculator

Perform one-sample and two-sample t-tests with t-statistic and p-value.

About Math & Science Calculators

The calculators in this category cover the everyday math behind US financial, tax, and academic decisions. The Percentage Calculator handles the work most people do without realizing it: figuring a tip, a sales-tax line, an APR comparison, or how much a 401(k) deferral cuts your take-home pay. The Standard Deviation Calculator and Probability Calculator show how spread out a data set is and how likely an outcome is, which matters when you weigh investment volatility or compare insurance scenarios.

Other tools answer concrete questions around the house and the classroom. The Area Calculator and Volume Calculator size flooring, paint, mulch, or concrete before you order materials. The Fraction Calculator keeps recipe scaling and measurement conversions exact, and the Quadratic Formula and Slope calculators back up algebra and geometry homework graded to Common Core and state standards.

Use them whenever a wrong number costs money or points: before signing a loan, ordering building supplies, checking a grade, or sanity-checking a figure a bank, the IRS, or a contractor handed you.

Frequently Asked Questions

How do I calculate a percentage increase or decrease correctly?
Subtract the original value from the new value, divide that difference by the original value, then multiply by 100. A jump from $50 to $60 is a 20% increase because 10 divided by 50 is 0.20. The order matters: dividing by the new value instead of the original is the most frequent error, and it understates raises, markups, and price hikes.
What's the difference between population and sample standard deviation, and which should I use?
Population standard deviation divides by the number of data points (N) and applies when your data covers the entire group you care about. Sample standard deviation divides by N minus 1 and applies when your numbers are a subset used to estimate a larger population. Most real-world finance and survey work uses the sample formula, since you rarely measure every member of a group.
Why do percentages and probabilities sometimes round in ways that don't add to 100%?
Each value is rounded on its own, so the displayed figures can total 99% or 101% even when the underlying math is exact. This rounding is normal and shows up on tax worksheets, poll results, and budget breakdowns. When the total has to land exactly on 100%, keep extra decimal places during the calculation and round only the final answer.
Are square footage and area the same thing for home projects?
Area is the general measurement of a flat surface in any unit, while square footage is that area expressed in square feet, the standard the US construction and real estate industries use. To convert square inches to square feet, divide by 144; to convert square yards to square feet, multiply by 9. Always measure in the same unit before multiplying length by width, or the result will be off by a large factor.
How accurate are online math calculators for tax and financial figures?
The arithmetic is exact, but the result is only as good as the rule or rate you plug in. Tax brackets, contribution limits, and wage bases change yearly, and figures like the IRS federal income tax brackets, which range from 10% to 37%, are set by statute and adjusted for inflation. For anything filed with the IRS, SSA, or a lender, confirm the current-year number against the agency's official publication before relying on it.