Math & Statistics
Fractions, percentages, base conversion, trigonometry, logarithms, boolean logic, statistics, regression, primes and geometry — verified against reference values.
Fraction Calculator
Add, subtract, multiply and divide fractions — simplified, with mixed numbers.
Calculate → PERCENTPercentage Calculator
X% of Y, X is what percent of Y, and percent change — three panels, one page.
Calculate → BASESBinary & Base Converter
Binary, octal, decimal and hex conversion plus binary arithmetic.
Convert → LOGICBoolean Algebra Calculator
Evaluate AND/OR/NOT/XOR/NAND/NOR expressions with full truth tables.
Evaluate → QUADRATICQuadratic Equation Calculator
Roots, double roots and complex cases with the discriminant explained.
Solve → PRIMESPrime Checker & Factorizer
Primality checks, complete factorizations and prime lists for any range.
Check → FACTORIALFactorial & Modulo
Exact factorials up to 500! with big-integer math, plus modulo remainders.
Calculate → LOGLogarithm Calculator
Log in any base — 10, e, 2 or custom — with ln and log10 alongside.
Calculate → TRIGTrigonometry Calculator
Sin, cos and tan in degrees or radians, with inverse functions.
Calculate →Standard Deviation Calculator
Population and sample SD, variance, mean, median and mode in one pass.
Calculate → REGRESSIONLinear Regression Calculator
Least-squares slope, intercept, correlation r and R² from x,y pairs.
Calculate → GEOMETRYGeometry Calculator
Area and volume for circles, rectangles, triangles, spheres and more.
Calculate →Unit Converters
Metric and imperial conversions with exact internationally defined factors — length, weight, volume, area, temperature, speed, CSS units and medical weights.
Length Converter
Meters, km, miles, feet, inches, yards and nautical miles at once.
Convert → WEIGHTWeight Converter
Kg, pounds, ounces, stones and tonnes — micrograms to tons.
Convert → VOLUMEVolume Converter
Liters, gallons, quarts, cups, fluid ounces and cubic feet.
Convert → AREAArea Converter
Square meters, feet, yards, acres, hectares and square miles.
Convert → TEMPERATURETemperature Converter
Celsius, Fahrenheit and Kelvin with the exact shift formulas.
Convert → SPEEDSpeed Converter
MPH, km/h, m/s, knots and ft/s for driving, running and sailing.
Convert → CSSCSS Unit Converter
PX, PT, REM and EM against your own base font size.
Convert → MCG ↔ MGMcg to Mg Converter
Microgram, milligram and gram — precision medical weight units.
Convert →How It Works — Three Easy Steps
No manual, no install, no account. Enter values, click once, read the answer.
- Pick your tool. Math calculators show their formulas and assumptions; unit converters show every target unit at once.
- Enter your values. Sensible defaults are pre-filled, and inputs explain exactly what they expect.
- Read the result. Instant, locally computed, with breakdowns and reference values where they help.
Frequently Asked Questions
Are these math and unit conversion tools free?
Yes. All 20 calculators and converters are completely free with no trial, no account, and no usage limits. They run directly in your browser.
Is my data uploaded when I use a calculator?
No. Every calculation runs locally in your browser. Your datasets, equations, and conversion values never leave your device.
How accurate are the unit conversions?
The conversion factors are the exact internationally defined values — 1 mile is precisely 1,609.344 meters and 1 US gallon is precisely 3.785411784 liters, applied at full precision.
Built on Verified Math
- Tested formulas. The core logic passes an automated suite covering known reference values — the classic SD dataset, exact mile-to-kilometer factors, discriminant cases.
- Full-precision factors. Unit conversions use internationally defined exact values, not rounded shortcuts.
- Estimates, not advice. For professional, medical, or financial decisions, confirm with a qualified expert.
Pick a Tool, Get the Number
Every calculator above answers instantly — on this device, with nothing uploaded.
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