Math & Units
Perform unit conversions and numerical calculations locally.
Available Tools (45)
← Back to all toolsUnit & Measurement Conversion
Unit Converter
Convert length, mass, temperature, area, volume, pressure, and data size using exact rational factors with zero server uploads.
Roman Numeral Converter (1 to 3,999,999)
Convert integers and Roman numerals up to 3,999,999 with vinculum overlines, symbol-by-symbol arithmetic and canonical spelling hints.
Date duration and working days
Calculate calendar and working days, weeks, hours and a countdown with a calendar timeline.
Angle: degrees, radians and gradians
Convert degrees, radians and gradians; show reduced π fractions and sin, cos and tan.
Force converter: N / dyne / lbf / kgf
Convert N, dyne, lbf and kgf and derive equivalent mass using standard gravity.
Torque converter and wrench force
Convert N·m, lb·ft and kgf·m and calculate force from a perpendicular lever arm.
Pressure converter: Pa, bar, psi, atm, mmHg, hPa, Torr
Convert seven pressure units locally, with gauge/absolute pressure notes and a qualified tire-pressure example.
Energy converter: J, cal, kcal, kWh, BTU, eV
Convert six energy units locally, with food-kilocalorie, electricity and cooling-power explanations.
Power converter: W, kW, hp, PS
Convert W, kW, mechanical hp and metric PS locally; derive energy from constant power and operating hours.
Tool category
Arbitrary-Precision BigInt Calculator
Arbitrary-Precision BigInt Calculator: Evaluates expression using native arbitrary-precision BigInt arithmetic without floating-point rounding.
IEEE 754 binary32 and binary64 bit visualizer
Explore binary32 and binary64 floating-point bits, bias, exact stored decimal values, signed zero, infinity and a fixed quiet NaN locally.
Scientific calculator: functions, angles and history
Calculate trigonometric, inverse, hyperbolic, logarithmic and factorial expressions with degree/radian mode, scientific keys and local page history.
Exact fraction calculator: expressions and steps
Evaluate nested rational expressions, mixed numbers and repeating decimals exactly with BigInt fractions and arithmetic steps.
Matrix Calculator: Inverse, Determinant & Operations
Add or multiply matrices, transpose A, calculate its determinant or follow a Gauss–Jordan inverse with every elementary row operation. Enter dimensions and values locally in your browser.
Complex Number Calculator & Polar Form
Add, subtract, multiply, divide, raise to a real power or conjugate complex numbers. Convert rectangular and polar inputs and inspect the Euler form and Argand diagram.
Prime Factorization, GCD & LCM Calculator
Factor positive integers below 2^63−1 with exact BigInt arithmetic. See prime powers, short division diagrams, Euclidean steps and the exact GCD and LCM, all calculated locally in your browser.
Percentage & Percentage Change Calculator
Switch between percent of a number, share of a total, and percentage change. See the difference, direction and formula steps with an explicit calculation base.
Significant Figures (Sig Figs) Formatter
Round decimal measurements and arithmetic expressions with exact half-even rounding. Count significant figures and display standard scientific notation.
Quadratic Equation Solver & Discriminant
Solve quadratic equations with exact fractional or radical roots, a step-by-step derivation, the vertex and a parabola graph.
Cubic Equation Solver (Cardano/Shengjin)
Solve cubic equations with exact discriminant classification, repeated-root multiplicities, three numerical roots and trigonometric or Cardano expressions.
Geometric Area & Volume Calculator (2D & 3D)
Calculate areas, volumes and related dimensions with exact expressions, decimal values, formulas and rotatable solid wireframes.
Vector Math Calculator (2D & 3D)
Calculate dot and cross products, norms, angles, unit vectors and projections with an interactive 3D direction diagram.
Modular Arithmetic & Multiplicative Inverse
Calculate exact modular sums, products, powers and inverses, with extended Euclidean steps and an RSA learning example.
Fibonacci Sequence & Golden Ratio
Calculate exact Fibonacci numbers through F2000, compare adjacent ratios with the golden ratio, and explore an animated golden spiral.
2D & 3D point distance: exact radicals
Calculate 2D or 3D Euclidean, Manhattan and Chebyshev distances, exact simplified radicals and signed coordinate differences locally.
Tool category
Descriptive Statistics Calculator
Calculate descriptive statistics, quartiles, modes, variation and IQR outliers with an interactive boxplot.
Normal Probability and Z-Score Calculator
Calculate Z-scores, normal cumulative probabilities and one- or two-tailed probabilities with an interactive bell curve.
Binomial & Poisson Probability Calculator
Calculate binomial and Poisson point and cumulative probabilities, expectation and variance with a distribution histogram.
Linear Regression & Correlation (r, r²)
Fit paired data by ordinary least squares; inspect scatter points, residuals, SSE, r² and predicted Y.
Simple & Exponential Moving Average (SMA/EMA)
Calculate trailing SMA and SMA-seeded EMA, compare all points on a line chart and export the complete series as CSV.
Permutation & Combination (nPr, nCr)
Calculate exact permutations and combinations with BigInt for n up to 10000. See every result digit and the complete factorial expansion.
Random Number Generator (Uniform & Gaussian)
Generate up to 50,000 uniform or Gaussian samples with Web Crypto, histogram, Q-Q preview, K-S statistic and CSV or JSON export.
Dice Roll Probability Simulator
Calculate exact dice probabilities, keep the highest dice, compare advantage or disadvantage, simulate 100,000 rolls and roll once.
Tool category
Compound Interest & Investment Calculator
Project monthly investments with annual, monthly or continuous compounding, an annual balance table, a contribution chart and inflation-adjusted purchasing power.
Loan Amortization & Mortgage Calculator
Compare level payments and equal principal, export monthly schedules, and compare lower payments with a shorter term after prepayment.
Rule of 72 Doubling Time Calculator
Compare the Rule of 72 with exact compound-growth formulas; calculate doubling time or the annual rate needed for a target time.
Shopping Discount & Sale Price Calculator
Calculate percentage or Chinese zhe discounts, one threshold reduction, total savings and optional tax.
VAT / GST & Sales Tax Calculator
Calculate tax-exclusive and tax-inclusive amounts with exact decimal cent rounding, invoice field guidance and dated official rate references.
Tip Calculator & Bill Splitter
Calculate tips, split a bill exactly to cents, or round each person’s payment up to a whole dollar with the extra tip shown.
Nominal APR to Effective Annual Rate (EAR / APY) Converter
Convert nominal APR and effective EAR/APY in either direction with six compounding frequencies, interest factors and a comparison chart.
Tool category
Ohm's Law & Electrical Power Calculator
Solve any two of voltage, current, resistance and power, with engineering units, the two applied formulas and a twelve-formula wheel.
Resistor Color Code Decoder (4/5/6 Bands)
Decode resistor bands, resistance range and temperature coefficient; generate exact color bands from a resistance value.
Decibel (dB, dBm, dBu) Gain Calculator
Convert power or voltage input/output to gain, gain to ratios, dBm to milliwatts, and dBu to RMS volts locally.
Sound Pressure Level (SPL) Attenuation
Estimate point-source sound level over distance, with optional humidity and frequency dependent atmospheric absorption.
Tank Volume & Liquid Weight Calculator
Calculate partially filled rectangular or cylindrical tanks, US and imperial gallons, liquid mass and current or full gross mass.