Math Calculators — Statistics, Geometry, Algebra & More
Free calculators for statistics and probability, geometry and trigonometry, algebra, percentages and number conversions — 40 tools that show the formula they use, run in your browser and need no signup.
New to percentages or triangles? Start with the percentage guide or how to find triangle angles.
Most-Used Calculators
The three groups people use most — percentages, triangles and statistics.
Percentage Calculator
Percent of a number, what percent one number is of another, and percent change.
- 15% of 80
- 12
- 12 is what % of 80?
- 15%
- Change from 50 to 65
- +30%
Triangle Calculator
Missing sides, angles and area of any triangle from three known values.
- Right triangle, legs 3 and 4
- Hypotenuse 5
- Area (½ × 3 × 4)
- 6
- Law of cosines
- c² = a² + b² − 2ab·cos C
Z-Score Calculator
How many standard deviations a value is from the mean, and its percentile.
- z = (x − μ) ÷ σ
- x = 85, μ = 70, σ = 10
- z = 1.5
- Percentile (normal distribution)
- ≈ 93.3%
All Math Calculators
40 calculators grouped by topic. Each tag shows the formula or method the calculator uses.
Statistics, Variance & Probability
9 toolsGeometry, Trigonometry & Vectors
9 toolsAlgebra, Polynomials & Functions
12 toolsPercentages & Ratios
2 toolsNumber Systems & Everyday Tools
8 toolsNo calculators match your search. Try a different word, or search the whole site.
Which Calculator Should You Use?
Match what you're trying to work out to a starting calculator and the one to use next.
| You Want To… | Start With | Then Use | Why |
|---|---|---|---|
| Summarize a set of numbers | Mean, Median & Mode | Standard Deviation | Find the center of the data first, then how spread out it is. |
| Compare a score with the average | Standard Deviation | Z-Score | A z-score needs the mean and standard deviation of the group. |
| Solve a right triangle | Pythagorean Theorem | Trigonometry | Get the missing side, then the angles from sine, cosine or tangent. |
| Solve an equation | Quadratic Formula | Polynomial | Find the roots, or expand and combine the expressions first. |
| Count possible outcomes | Permutation & Combination | Binomial Probability | Count the arrangements, then the chance of a given number of successes. |
| Check a lab measurement | Percent Error | Significant Figures | Compare with the accepted value, then report to the right precision. |
Methodology & Accuracy
Builds and maintains every CalculatePilot calculator, checking each formula and worked example by hand and re-verifying pages on a regular schedule.
Calculations use standard double-precision (IEEE 754) arithmetic — about 15–17 significant digits — and results are rounded for display. Each page states its formula and any limits, such as sample versus population statistics.
CalculatePilot. (2026). Math calculators [Web application]. https://www.calculatepilot.com/math-calculators.html
Frequently asked questions
What's the difference between sample and population standard deviation?
Population standard deviation divides the squared deviations by N, the number of values, and is used when you have every member of the group. Sample standard deviation divides by n − 1 (Bessel's correction), which gives a better estimate of the population's spread when your data is only a sample.
What's the difference between a permutation and a combination?
In a permutation the order matters, so ABC and CBA count as different arrangements. In a combination the order doesn't matter, so they count as the same selection. For the same n and r there are always at least as many permutations as combinations: nPr = nCr × r!.
Why do some results show tiny rounding differences?
Computers store most decimals in binary floating point (IEEE 754 double precision), which can't represent numbers like 0.1 exactly — for example 0.1 + 0.2 is stored as 0.30000000000000004. Results are rounded for display, so these tiny differences rarely matter, but for exact work use fractions or the precision your course requires.
Do these calculators store the numbers I enter?
No. The calculations run in your browser and the numbers you enter aren't sent to or stored on our servers. Like most websites, the site itself uses analytics and advertising cookies — see our privacy policy for details.
Can I use these calculators for homework?
Yes — they're a good way to check your answers. Each page shows the formula, so you can follow the method, but follow your teacher's rules on rounding, significant figures and showing your working.