Free online calculators and math tools for exams, engineering and the lab.
25 tools that show their working. They run in your browser, with no account and nothing to install.
All tools
25 tools
Calculators
Keypads that work like the calculators on the exam desk.
- Scientific CalculatorCasio-style calculator with 8 modes: fractions, equations, matrices, complex numbers, base-N and statistics.3/8 + 5/12 = 19/24
- TI-36X Pro Style CalculatorNewTI-36X Pro style keypad with MathPrint fractions, FE exam solvers, d/dx, integrals, constants and a TI-30XS layout.x² − 5x + 6 = 0 → x = 3, 2
- GATE-Style Virtual CalculatorNewPractice version of the GATE on-screen calculator: same key order, a timed exam mode and numerical answer drills.log₂ 1024 = 10
- BA II Plus Style CalculatorNewFinancial keypad with TVM, cash flow NPV and IRR, bonds, amortization and depreciation, plus step-by-step forms.360 N, 6 I/Y, 300,000 PV → PMT −1,798.65
- Construction CalculatorNewFeet-inch-fraction keypad with tape and memory, stair layout with code checks, and rafter, hip and jack lengths.5′ 7⅜″ + 2′ 9⅝″ = 8′ 5″
Math
Graphs, calculus, matrices, numbers and data.
- Graphing CalculatorPlot functions, implicit curves, inequalities, polar and parametric graphs, with sliders.x² − 2 = x at x = −1 and 2
- 3D Graphing CalculatorSurfaces, implicit surfaces, space curves, cylindrical and spherical plots, vector fields.z = x² − y², a saddle at the origin
- Derivative CalculatorDerivatives with every rule shown, higher orders, partials, implicit dy/dx and tangent lines.d/dx x² sin x = 2x sin x + x² cos x
- Integral CalculatorDefinite integrals, area under a curve, Riemann sums, volumes of revolution, double integrals.∫₀³ x² dx = 9
- Matrix CalculatorDeterminant, inverse, RREF with row operations, eigenvalues and systems, up to 6x6 in exact fractions.[2 1; 5 3]⁻¹ = [3 −1; −5 2]
- Statistics CalculatorMean, SD, quartiles, outliers, regression with R², and normal, t, chi-square and F distributions.t(0.975, 10 df) = 2.228
- Complex Number CalculatorNewRectangular, polar and exponential forms with working, all n-th roots, an Argand diagram and AC phasors.(3 + 4i)(1 − 2i) = 11 − 2i
- Binary CalculatorNewBase conversion with steps, a programmer view with bitwise ops and overflow, and an IEEE-754 float decoder.−5 in 8 bits = 1111 1011
- Unit Converter19 engineering categories plus a free-form box for compound units like 9.81 m/s^2 to ft/s^2.32 psi = 220.63 kPa
Engineering
Networks, power, cables, batteries and beam sections.
- Subnet CalculatorNewIPv4 and IPv6 subnets with the binary working, split and summarize, VLSM planning and CCNA-style practice.192.168.10.37/26 → 192.168.10.0, 62 hosts
- Voltage Drop CalculatorNewVoltage drop and wire size for NEC, BS 7671, IEC and AS/NZS limits, in AWG or mm², with the working shown.16 A, 30 m of 2.5 mm² Cu at 230 V → 3.44%
- Three-Phase Power CalculatorNewkW, kVA, kVAR and current with star and delta values, power factor correction and a capacitor resonance check.400 V, 32 A, PF 0.85 → 18.84 kW
- Battery CalculatorNewBattery runtime with Peukert, 13S4P-style pack design, inverter and off-grid bank sizing, and charge time.13S4P of 3.6 V 3 Ah cells = 46.8 V, 12 Ah
- Moment of Inertia CalculatorNewCentroid, Ix, Iy, principal axes, section modulus for 11 shapes and built-up sections, with the table working.200 × 300 mm: Iₓ = 450 × 10⁶ mm⁴
Science and health
Lab solutions, uncertainty, sample sizes and dosage maths.
- Molarity CalculatorNewGrams from any formula or hydrate, C1V1 dilutions, serial dilutions, lab recipes with a prep sheet, and buffers.250 mL of 0.5 M NaCl = 7.305 g
- Error Propagation CalculatorNewUncertainty of any formula with symbolic partial derivatives, an error budget and a Monte Carlo check.12.0 ± 0.1 V ÷ 2.00 ± 0.02 A = 6.00 ± 0.08 Ω
- Sample Size CalculatorNewSurvey and study sample sizes with power analysis for t-tests, ANOVA, proportions, correlation and chi-square.95%, ±5%, p = 0.5 → n = 385
- Nursing Dosage CalculatorNewDose, IV drip and infusion maths worked three ways, with practice problems and alligation for nursing and pharmacy.500 mg ordered, 250 mg/5 mL → 10 mL
Students and travel
Grade points and the Schengen 90/180 rule.
- NEB GPA CalculatorClass 11 and 12 GPA from theory and practical marks or grades, by the NEB 2083 grading rules.A+ in every subject → GPA 4.00
- Schengen CalculatorNewSchengen 90/180 days: days used, days left, latest exit and earliest return, plus days per country for tax.1 Mar to 29 May = 90 of 90 days
No tool matches yet. Try a shorter word, or tell us what you need at [email protected].
Start from the task. The right tool follows.
- Work out 3/8 + 5/12 as an exact fraction, solve a quadratic, convert to binaryScientific Calculator
- Practise FE exam key sequences on a TI-36X Pro style keypadTI-36X Pro Style Calculator
- Get used to the GATE exam's on-screen calculator before exam dayGATE-Style Virtual Calculator
- Solve a CFA time value of money, NPV or IRR question with BA II Plus style keystrokesBA II Plus Style Calculator
- Add feet, inches and fractions, lay out a stair stringer or work out a rafter lengthConstruction Calculator
- See what y = x² − 4 looks like, shade y > 2x + 1, plot r = 1 + cos θGraphing Calculator
- Picture z = x² − y², a sphere and a plane, or a helix for a Calc 3 problem3D Graphing Calculator
- Check d/dx of x² sin x and see which rule applies whereDerivative Calculator
- Area under a curve, a Riemann sum, or the volume when a curve spins around an axisIntegral Calculator
- Row-reduce a 4 × 5 system, invert a 3 × 3, find eigenvaluesMatrix Calculator
- Mean and standard deviation of lab readings, a regression line, a t critical valueStatistics Calculator
- Multiply (3 + 4i)(1 − 2i), switch to polar form, or combine impedances in an AC circuitComplex Number Calculator
- Convert 255 to binary and hex, read a two's complement byte, decode an IEEE 754 floatBinary Calculator
- Turn 32 psi into kPa or 250 N·m into lbf·ftUnit Converter
- Find the network, broadcast and hosts of 192.168.10.37/26, or plan a VLSM schemeSubnet Calculator
- Check the voltage drop on a cable run and find the smallest size that meets the limitVoltage Drop Calculator
- Turn 400 V and 32 A at power factor 0.85 into kW, or size a power factor correction bankThree-Phase Power Calculator
- Estimate how long a battery runs a load, or design a lithium pack such as 13S4PBattery Calculator
- Find the centroid and second moment of a T-beam, with the parallel axis workingMoment of Inertia Calculator
- Weigh out 250 mL of 0.5 M NaCl, plan a serial dilution or make up a bufferMolarity Calculator
- Propagate the uncertainty in g = 4π²L/T² from a pendulum labError Propagation Calculator
- Size a survey at 95% confidence and ±5%, or a two-group study for 80% powerSample Size Calculator
- Check a dosage calculation practice problem three ways, or work out an IV drip rateNursing Dosage Calculator
- Work out a Class 11 or 12 NEB GPA from your theory and practical marksNEB GPA Calculator
- Count your days under the Schengen 90/180 rule and find your latest exit dateSchengen Calculator
How we build them. Four rules every tool keeps.
Exact where it matters
The calculator keeps fractions and surds exact, so 0.1 + 0.2 gives 3/10. The matrix calculator works in exact fractions, so an inverse never turns 1/3 into 0.3333.
Working you can follow
Derivatives list every rule and row reduction every row operation. The engineering, lab and finance tools print the formula with your numbers in it, the way you would write it in an exam answer.
Honest about limits
When a tool cannot do something, it says so. The integral tool reports a divergent integral as divergent, and the voltage drop tool tells you it does not check cable ratings.
Checked examples
Every worked example on a tool page was computed with that tool and checked against an independent method, a textbook or a published example before it went live.
Guides and articles. For the topics behind the tools.
The calculator guides walk through common course topics with worked examples, such as solving quadratic equations, standard deviation by hand and by calculator and complex numbers in rectangular and polar form.
The WideMath blog answers questions like why sin 30 can come out as -0.988 and whether 6÷2(1+2) is 1 or 9. On the scientific calculator, the tabs above the history open a graph, a 3D view, the integral tool or the unit converter beside the keypad.
Questions. Short answers.
Is WideMath free?
Yes. Every tool on WideMath is free to use, with no account and no download, and the site is paid for by ads. Everything runs in your web browser, on a laptop or a phone.
Why are there ads on WideMath?
Ads pay for the domain, the hosting and the time we spend building new tools, so every calculator stays free with no sign-up. The calculators other sites embed and the browser extension carry no ads.
Do I need to sign up or install anything?
No. Open a tool and start typing. Many tools keep your inputs in the page address, so you can bookmark a problem or send the link to someone.
Are the step-by-step solutions free?
Yes. The tools show their working at no cost: the derivative calculator lists every rule, the matrix calculator every row operation, and the engineering and lab tools show each formula with your numbers in it.
Are the exam-style calculators allowed in the exam?
No, and they are not meant to be. The TI-36X Pro style, BA II Plus style and GATE-style calculators are for practice, so the key sequences feel familiar. In the exam you use the approved handheld calculator, or the on-screen one the exam provides.
Can I rely on the medical and electrical tools?
They are built for learning and for checking your own working. The dosage tool is for practising dosage calculations, not for clinical decisions, and the voltage drop tool checks voltage drop only, not cable ratings. Follow your local code and your facility's protocols.
Is WideMath made by Casio or Texas Instruments?
No. WideMath is an independent project made in Nepal, with no connection to Casio or Texas Instruments. Some calculators follow the key layout of well-known models so that the key sequences you practise carry over to the exam hall.
Made in Nepal by three engineering students.
We are Anuj Paudel, Ashish Pandey and Jhalak Prasad Pandey. We wanted a free calculator that behaves like the one on the exam desk, then kept building the tools our classmates, friends and readers asked for. Read why we built WideMath.
Found a wrong answer, or need a tool we do not have yet? Write to [email protected]. We read every message.