教育与数学
为学生和专业人士提供分步公式和实例讲解的数学与统计计算器。
百分比计算器
三种方式计算百分比:求某数的百分之几、求一个数是另一个数的百分之几、计算两数之间的百分比变化。
Percentage Increase Calculator
Calculate percentage increase between two values with the standard formula, a worked step-by-step example, and the absolute difference shown alongside.
Percentage Decrease Calculator
Calculate percentage decrease between two values with the standard formula, a worked example, and the absolute difference shown alongside the result.
Fraction Calculator
Add, subtract, multiply and divide fractions with automatically simplified results, the decimal equivalent, and step-by-step formulas for each operation.
Decimal to Fraction Calculator
Convert any terminating decimal to a simplified fraction with the place-value method, plus the equivalent percentage. Example: 0.625 = 5/8 = 62.5%.
Ratio Calculator
Simplify a ratio to lowest terms, express it in 1:n form, and scale it to a new first term. Example: 4:6 simplifies to 2:3 and scales to 10:15.
Average Calculator
Calculate the average (arithmetic mean) of a list of numbers, with the sum, count, minimum and maximum shown alongside. Includes a worked example.
Scientific Calculator
Free online scientific calculator: trig in radians or degrees, roots, logs, exponents, constants pi and e — evaluated with a safe whitelist expression parser.
Mean Calculator
Calculate the arithmetic, geometric and harmonic means of a data set, with formulas, a worked example, and guidance on when each mean is appropriate.
Median Calculator
Find the median, mode and range of a data set with worked examples. Handles even-sized lists and multiple modes, and explains median vs mean for skewed data.
Standard Deviation Calculator
Calculate sample and population standard deviation, variance and mean for any data set, with the n-1 vs n distinction explained and a worked example.
Probability Calculator
Calculate the probability of two independent events: both occurring, either occurring, neither occurring, and the complement — with formulas and examples.
Sample Size Calculator
Calculate the survey sample size you need using Cochran's formula with finite population correction, at 90%, 95% or 99% confidence and your margin of error.
Confidence Interval Calculator
Calculate a z-based confidence interval for a mean from the sample mean, standard deviation and size, with the margin of error and standard error shown.
Z-Score Calculator
Calculate a z-score from a value, mean and standard deviation, plus the normal-distribution percentile and the share of values above. Worked example inside.
Quadratic Equation Calculator
Solve ax^2 + bx + c = 0 with the quadratic formula. Shows real or complex roots and the discriminant, with a worked step-by-step example.
Log Calculator
Calculate logarithms in any base with the change-of-base formula, plus the natural log (ln), common log (log10) and binary log (log2) shown together.
Exponent Calculator
Raise any base to any power, including negative and fractional exponents, with the result in plain and scientific notation and the exponent rules explained.
Prime Number Calculator
Check whether a number is prime, get its full prime factorization, and find the next prime — with trial division explained and worked examples.
Matrix Calculator
Calculate the determinant, trace and (for 2x2) inverse of a 2x2 or 3x3 matrix from row-major entries, with cofactor expansion shown step by step.