A tool for your next question
Math calculators
Choose a tool by the question in front of you. Solve a percentage, check an expression, compare measurements or summarize a data set. Use the explanation to understand why the answer makes sense.
Everyday arithmetic
Find a percentage, undo a discount or work with fractions. Identify the original whole before choosing a percentage formula.
Expressions and geometry
Check brackets, angle units and dimensions. An area uses square units, while a volume uses cubic units.
Scientific Calculator
sin, cos, tan, log, ln, √, x², exponents, factorial
Area Calculator
Circle, rectangle, triangle, trapezoid, ellipse, parallelogram — metric & imperial
Volume Calculator
Sphere, cylinder, cone, cube, rectangular prism — metric & imperial
Pythagorean Theorem Calculator
a² + b² = c². Find hypotenuse or any leg. Pythagorean triples.
Statistics and probability
Describe the data before interpreting it. Sample and population calculations serve different purposes, and a statistic depends on its assumptions.
Statistics Calculator
Mean, median, mode, std dev (sample & population), variance, IQR
Mean Median Mode Calculator
Mean, median, mode, range from any data set
Standard Deviation Calculator
Population (σ, ÷n) and sample (s, ÷n−1) standard deviation with deviation table
Probability Calculator
P(A∪B), P(A∩B), P(A|B), P(A') — union, conditional
Grades and learning
Use your actual assessment weights and institution’s scale. Different grading systems cannot always be converted by a single percentage rule.
Grade Calculator
Weighted grades — US letter, UK Honours, German, French scales
GPA Calculator
US 4.0, UK Honours, German 1–4, Australian HD, Chinese 百分制
Z-Score Calculator
Z-score, percentile, probability — left/right/two-tailed
Confidence Interval Calculator
CI for mean or proportion — 90/95/99% confidence
A percent change is not a percentage-point change
A rate moving from 4% to 5% rises by one percentage point, or 100 basis points. Its relative increase is 25%. The percentage calculator shows these quantities together so you can choose the wording your comparison needs.
Make the calculation reproducible
Keep the unrounded inputs, state any angle convention, and round at the end. For example, 2 + 3 × 4 equals 14 because multiplication comes before addition. Use brackets if you intend (2 + 3) × 4 = 20.
FAQ
Frequently asked questions
Where can I calculate a reverse percentage? ▾
Which calculator accepts a typed mathematical expression? ▾
Why might two calculators show slightly different answers? ▾
Sources & Methodology
This topic page helps you choose a tool. Read the individual calculator’s assumptions, source dates and limitations before relying on its estimate.
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