Percentages, fractions, GCF and LCM, powers and roots for schoolwork, shopping and everyday numbers.
Free · No sign-up · Every step shown
Free Online Math Calculators with Step-by-Step Solutions
Solve percentages, fractions, equations, statistics and geometry problems, and see the working behind every answer. Built for students, parents and anyone who wants to understand the result, not just copy it.
- Convert the percent: 15 ÷ 100 = 0.15
- Multiply: 0.15 × 80 = 12
15% of 80 = 12
16math calculators
Every stepshown, not just the answer
No sign-upfree on any device
Checkedagainst textbook formulas
Math calculators by topic
Pick a topic to see every calculator in it, or jump straight to a tool.
Linear equations, quadratics and systems of equations solved step by step, with a check.
Mean, median, mode, standard deviation, z-scores and probability counting (nPr, nCr).
Area, volume, circles, right triangles, slope and distance, with the formula shown.
Which math calculator do you need?
Search by the problem in front of you.
| If you want to… | Use the |
|---|---|
| Work out a discount, tip or test score | Percentage Calculator |
| Add, subtract or simplify fractions | Fraction Calculator |
| Find a common factor or common denominator | GCF and LCM Calculator |
| Solve an equation like 2x + 3 = 5x − 9 | Linear Equation Calculator |
| Solve an equation with x² | Quadratic Formula Calculator |
| Find the average of a list of numbers | Mean, Median, Mode Calculator |
| Measure how spread out your data is | Standard Deviation Calculator |
| Find the missing side of a right triangle | Pythagorean Theorem Calculator |
| Find the slope of a line or the distance between two points | Slope, Distance and Midpoint Calculator |
| Find the area of a room, triangle or circle | Area Calculator |
| Find the volume of a cylinder, cone or sphere | Volume Calculator |
| Find a circle’s circumference from its radius | Circle Calculator |
| Find a power, square root or cube root | Exponent and Root Calculator |
| Solve two equations with two unknowns | System of Equations Calculator |
| Find a z-score or percentile | Z-Score Calculator |
| Count arrangements or combinations (nPr, nCr) | Permutation and Combination Calculator |
How the step-by-step calculators work
- Enter your numbers
Type values into the boxes. Each field is labelled, and invalid input gets a clear message.
- Read the working
See the formula, your numbers substituted in and each line of the calculation.
- Check and learn
Compare with your own method. Worked examples and common mistakes sit below every tool.
Why students and parents use Longhand
Working, not just answers
Most online calculators return a number. Ours explain how it was found, which is what teachers ask for.
Edge cases handled
No solution, undefined slope, repeated roots and zero denominators each get a plain-English explanation.
Private by design
Calculations stay in your browser. Nothing you type is sent to a server or saved.
Fast on any phone
Lightweight pages with no sign-up wall, built mobile first so they load quickly on slow connections.
Built and checked by a real person
I am Shaheer Bin Ramzan, a software engineer and SEO specialist from Pakistan. I built Longhand because the maths tools I found were scattered across many sites and often gave an answer with no explanation. Every formula here is tested against worked examples and referenced to a textbook.
Frequently asked questions
Are Longhand’s online math calculators free to use?
Yes. Every calculator is free, with no sign-up, no login and no usage limit. The numbers you enter are processed in your browser and are not sent to our server, so you can use the tools without creating an account or sharing personal information.
Do the calculators show step-by-step solutions?
Yes. Each calculator writes out the formula, substitutes your numbers and shows every step to the final answer. Special cases, such as an undefined slope or an equation with no solution, are explained instead of returning an error, so you can follow the method.
How accurate are these math calculators?
Each calculator uses a standard textbook formula and is tested against hand-worked examples, including zero, negative numbers and invalid input. Results are rounded only at the end, to 12 significant digits. The formula sources are listed on our About page so you can check them yourself.
Can I use them to check my homework?
Yes, they work well as a checker. Solve the problem yourself first, then compare your answer and working with the calculator’s steps. If they differ, find the line where your method changed. That habit teaches more than copying an answer.
Which calculator should I use for percent change?
Use the percentage calculator and choose “Percent change from X to Y”. It divides the difference by the old value, so a rise from 800 to 880 shows as a 10% increase. For a discount, find X% of the price and subtract it.
What is the difference between standard deviation and variance?
Variance is the average squared distance from the mean. Standard deviation is its square root, which returns the result to the original units. Our calculator shows both for a sample and a population, so you can use whichever your course or report needs.
Do you store the numbers I enter?
No. Calculations run in your browser with JavaScript, and your inputs are not sent to our server or saved. Our web host keeps standard server logs, as described in the Privacy Policy.
Can I suggest a new calculator?
Yes. Email contact@onlinemathcalculators.com with the calculator you need. We add a tool only when we can verify the formula and explain it properly, so requests with a clear use case get priority.
Ready to solve your next problem?
Pick a calculator, enter your numbers and see the working in seconds.