Percentages
3 calculators
Arithmetic & Fractions
5 calculators
Popular
Fraction Calculator
Add, subtract, multiply and divide fractions
1.5M+ searches/month
Decimal to Fraction
Convert any decimal to a simplified fraction
700K+ searches/month
Ratio Calculator
Simplify ratios and solve proportions
500K+ searches/month
Greatest Common Factor
Find the GCF of two or more numbers
400K+ searches/month
Least Common Multiple
Find the LCM of two or more numbers
400K+ searches/month
Mixed Number Calculator
Add, subtract and convert mixed numbers
300K+ searches/month
Algebra & Numbers
7 calculators · 2 converters
Popular
Square Root Calculator
Square root and nth root of any number
800K+ searches/month
Exponent Calculator
Any base raised to any positive or negative power
400K+ searches/month
Scientific Notation Calculator
Convert to and from scientific notation
300K+ searches/month
Roman Numeral Converter
Convert between Roman and Arabic numerals
800K+ searches/month
GPA Calculator
Semester and cumulative GPA calculator
800K+ searches/month
Prime Number Calculator
Check if a number is prime, find prime factors
300K+ searches/month
Logarithm Calculator
Log base 10, natural log and any base
250K+ searches/month
Unit Converter
Length, weight, volume, speed and more
5M+ searches/month
Area Converter
Acres, hectares, sq ft, sq meters and more
600K+ searches/month
Geometry
4 calculators
Popular
Area Calculator
Area of circles, squares, rectangles and triangles
500K+ searches/month
Volume Calculator
Volume of spheres, cubes, cylinders and more
300K+ searches/month
Pythagorean Theorem
Find hypotenuse or missing leg of a right triangle
400K+ searches/month
Circumference Calculator
Circle circumference, area and diameter
400K+ searches/month
Slope Calculator
Find slope from two points on a line
400K+ searches/month
Triangle Calculator
Find angles, sides and area of any triangle
300K+ searches/month
Statistics
2 calculators
Why Use Our Math Calculators
25 free math calculators that show every step, from percentages and fractions to triangles, logarithms and standard deviation. Each one handles the awkward cases (zero, negatives, huge numbers) and explains the answer instead of just printing it.
Our math tools are built for accuracy and speed. The percentage calculator handles all three common question types: what is X% of Y, X is what percent of Y, and percentage change between two values. The fraction calculator shows full step-by-step working, not just the answer, which makes it genuinely useful for students who need to understand the process.
For students, these tools work best alongside your own work, not instead of it. Use the square root calculator to check your manual calculations, the GPA calculator to track your academic progress, and the percentage calculator for everyday arithmetic that most people reach for a calculator to solve anyway.
All tools run in your browser with no data sent to our servers. Results are instant and accurate to standard mathematical conventions.
Which Calculator Answers Your Question
| Your question | Use this |
|---|---|
| What is 15% of 80? | Percentage Calculator |
| By what percent did it go up or down? | Percentage Change Calculator |
| How do I add or divide fractions? | Fraction Calculator |
| What is my GPA? | GPA Calculator |
| How long is the third side of a right triangle? | Pythagorean Theorem Calculator |
| What is the area of this room or shape? | Area Calculator |
| What is the mean, median and mode? | Average Calculator |
| How spread out is my data? | Standard Deviation Calculator |
Formula Cheat Sheet
| Task | Formula | Example |
|---|---|---|
| Percent of a number | part = percent ÷ 100 × whole | 15% of 80 = 12 |
| Percentage change | (new − old) ÷ |old| × 100 | 50 to 65 = +30% |
| Average (mean) | sum ÷ count | (4 + 8 + 9) ÷ 3 = 7 |
| Area of a circle | π × r² | r = 3 gives 28.27 |
| Pythagorean theorem | a² + b² = c² | 3, 4 gives 5 |
| Slope of a line | (y₂ − y₁) ÷ (x₂ − x₁) | (1,2) to (3,8) = 3 |
| Adding fractions | a/b + c/d = (ad + bc) ÷ bd | 1/2 + 1/3 = 5/6 |
| Logarithm | logb(x) = ln(x) ÷ ln(b) | log2(8) = 3 |
Sources. Standard formulas; every example above was computed and checked against the calculators on this site.
Math Questions
Common questions about percentages, fractions, geometry and statistics.
Formula: ((New, Old) / Old) × 100. Example: from 80 to 100 is ((100 to 80) / 80) × 100 = 25% increase. Use the Percentage Change Calculator for instant results with both increase and decrease.
Divide both numerator and denominator by their GCF. Example: 12/18, GCF is 6, so 12/6 = 2 and 18/6 = 3, giving 2/3. Use the Fraction Calculator which automatically simplifies all results.
Non-perfect squares have irrational square roots. √2 = 1.41421356, √3 = 1.73205080, √5 = 2.23606797: these decimals go on forever without repeating. Use the Square Root Calculator for any number, including cube roots and nth roots.
Area = π × radius². For radius 5: Area = 3.14159 × 25 = 78.54 square units. From diameter: Area = π × (diameter / 2)². Use the Area Calculator for circles, squares, rectangles and triangles.
In any right triangle: a² + b² = c², where c is the hypotenuse. To find hypotenuse: c = √(a² + b²). Legs of 3 and 4 give hypotenuse = √25 = 5. Use the Pythagorean Theorem Calculator to find any missing side.
I=1, V=5, X=10, L=50, C=100, D=500, M=1000. Subtract when a smaller numeral precedes a larger one: XIV = 10 + (5 to 1) = 14. MCMXCIX = 1000 + 900 + 90 + 9 = 1999. Use the Roman Numeral Converter for instant two-way conversion.
Steps: find the mean, subtract mean from each value and square it, average those squared differences (= variance), take the square root. Use population SD when you have all data; sample SD (divides by n to 1) for a subset. Use the Standard Deviation Calculator for any dataset.
The GCF is the largest number dividing evenly into two or more numbers. For 24 and 36: factors of 24 are 1,2,3,4,6,8,12,24; factors of 36 are 1,2,3,4,6,9,12,18,36; GCF = 12. Use the GCF Calculator for any set of numbers instantly.
Slope = rise / run = (y2, y1) / (x2, x1). For points (2, 3) and (6, 11): slope = (11 to 3) / (6 to 2) = 2. Positive slope goes up, negative goes down, zero is horizontal, undefined is vertical. Use the Slope Calculator with any two coordinate points.
Probability = favorable outcomes / total possible outcomes. Rolling a 3 on a six-sided die: 1/6 = 16.67%. Ranges from 0 (impossible) to 1 (certain). For independent events, multiply individual probabilities. Use the Probability Calculator for single and combined events.
🔍
No calculators found
Try a different search term