Science Tools
Math Calculator
Free online scientific calculator: expression evaluation, trigonometry, logarithms, factorial, permutations, combinations, big numbers, and complex numbers. Supports DEG/RAD/GRAD angle modes. All…
Math Converter
Free online math converter: number base conversion, angle units, Cartesian-polar coordinates, scientific notation, and Roman numerals. All processing is local — no data uploaded.
Math Equation Solver
Free online equation solver: linear equations, quadratic equations, cubic equations, systems of linear equations, numeric root finding via Newton-Raphson, and inequality solving. Powered by Math.js…
Math Formula Reference
Free online math formula reference: algebra, geometry, trigonometry, calculus, and statistics formulas organized by category with search. All content is local — no data uploaded.
Math Geometry
Free online geometry calculator: area, perimeter, volume for 2D and 3D shapes, plus an interactive triangle solver. All calculations are local.
Math Grapher
Free online function grapher: plot multiple functions, find intersections, display extrema, show derivative curves. Supports Cartesian and polar coordinates. Powered by function-plot. All processing…
Math Matrix
Free online matrix calculator: addition, subtraction, multiplication, transpose, determinant, inverse, adjugate, rank, trace, eigenvalues, eigenvectors, LU decomposition, and linear system solver…
Math Number Theory
Free online number theory calculator: prime checker, factorization, GCD/LCM, modular exponentiation, modular inverse, totient, divisor functions. All processing is local.
Math Sequences
Free online sequences and series calculator: arithmetic progression, geometric progression, Fibonacci sequence, series summation, and convergence tests. All processing is local.
Math Statistics
Free online statistics calculator: descriptive statistics, frequency distribution, linear regression, correlation, and hypothesis testing. All processing is local — no data uploaded.
Percentage Calculator
Free online percentage calculator with seven plain-language question cards: what is X% of Y, X is what percent of Y, percent change, add or subtract a percent (tax, tip, discount), reverse from the…
Ratio Calculator
Free online ratio and proportion calculator. Solve A:B = C:D for any missing term, simplify ratios including decimals, scale recipes and ingredient lists to a new yield, find the aspect ratio of any…
Physics Astro
Free online astrophysics calculator: escape velocity, orbital velocity, Kepler's third law, Schwarzschild radius, rocket equation, and Hubble distance.
Physics Circuits
Free online electricity calculator: Ohm's law, series/parallel resistors, capacitor energy, Coulomb's law, and electrical power. All calculations local — no data uploaded.
Physics Constants
CODATA 2018 physical constants reference: 100+ fundamental physics constants with symbol, value, unit, and uncertainty. Search and filter by category.
Physics Fluids
Free online fluid mechanics calculator: buoyancy, Bernoulli's equation, flow rate, hydrostatic pressure, Stokes' law, and Reynolds number.
Physics Mechanics
Free online mechanics calculator: projectile motion, free fall, inclined plane friction, Newton's second law, momentum impulse, and work-energy-power. All calculations local — no data uploaded.
Physics Modern
Free online modern physics calculator: time dilation, de Broglie wavelength, photoelectric effect, E=mc², half-life, and Bohr hydrogen levels.
Physics Optics
Free online optics calculator: Snell's law, lens/mirror equations, critical angle, diffraction grating, and Brewster's angle.
Physics Rotation
Free online rotation calculator: centripetal force, angular velocity conversion, torque, moment of inertia, angular momentum, and centrifugal force.
Physics Simulations — Interactive Canvas Animations
Free online physics simulations: projectile motion, pendulum, wave interference, electric field lines, and force vector composition. Real-time interactive Canvas animations.
Physics Thermo
Free online thermodynamics calculator: ideal gas law, heat transfer, thermal expansion, temperature conversion, Carnot efficiency, and combined gas laws.
Physics Uncertainty
Free online uncertainty calculator: significant figures counter, error propagation (addition/multiplication/power), standard deviation, extended uncertainty analysis.
Physics Units
Free online physics unit converter: convert between 200+ units across length, mass, force, energy, power, pressure, temperature, velocity, frequency, charge, voltage, magnetic flux and more.
Physics Vectors
Free online vector calculator: 2D and 3D vector decomposition, dot product, cross product, angle, unit vector, addition with Canvas arrow visualization.
Physics Waves
Free online waves calculator: simple harmonic motion, pendulum period, wave speed, Doppler effect, resonant frequency, and beat frequency.
Chemistry Acidbase
Free acid-base chemistry calculator: pH/pOH/[H+]/[OH-] converter, Ka-Kb-pKa-pKb, Henderson-Hasselbalch buffer, and Canvas titration curves.
Chemistry Bonding
Free chemical bonding calculator: Lewis structures, formal charge, VSEPR geometry prediction, hybridization, and molecular polarity analysis.
Chemistry Data
Free chemical reference data: solubility rules, polyatomic ions, strong acids/bases, activity series, chemical constants, and indicators.
Chemistry Electron
Free electron configuration calculator: Aufbau filling, orbital box diagrams, quantum numbers (n,l,ml,ms), and Canvas-rendered s/p/d orbital shapes.
Chemistry Equation
Free chemical equation balancer: balance equations using Gaussian elimination, stoichiometry calculator, limiting reagent finder, percent yield, reaction type classification.
Chemical Equilibrium Calculator — Kc, ICE Table, Kp, Gibbs
Chemical equilibrium calculator: Kc expression, ICE table solver, Kp/Kc conversion, ΔG° to K, reaction quotient Q vs K, Le Chatelier prediction.
Gas Laws Calculator — Ideal Gas, Boyle, Charles, Gay-Lussac
Gas laws calculator: Ideal Gas (PV=nRT), Boyle, Charles, Gay-Lussac, Combined, Dalton, Graham, Van der Waals. Unit conversion atm/kPa/mmHg.
Chemistry Kinetics
Chemical kinetics calculator: rate law (0/1/2 order), integrated rate equations, half-life, Arrhenius equation (k=A·e^(-Ea/RT)), activation energy.
Chemistry Mass
Free molar mass calculator: compute molecular weight, percent composition, empirical formula, molecular formula, and convert between moles, grams, and particles.
Chemistry Nuclear
Free nuclear chemistry tools: Monte Carlo radioactive decay simulation with Canvas animation, half-life calculator, decay constant converter, and radioactive dating (14C, 40K/40Ar, 238U/206Pb).
Chemistry Organic
Free organic chemistry reference: IUPAC naming guide for 10 compound classes, functional group priority, isomer types, and reaction cards.
Chemistry Periodic Table
Free interactive periodic table: 118 elements with atomic mass, electron configuration, electronegativity, radius, ionization energy, isotopes, and periodic trend charts.
Chemistry Redox
Free redox chemistry calculator: oxidation state analysis, half-reaction balancing, standard reduction potentials, and Nernst equation.
Chemistry Solutions
Free solution calculator: molarity, molality, normality, dilution (C1V1=C2V2), percent solutions (w/v, v/v, w/w), PPM/PPB conversion, solution preparation guide.
Chemistry Spectroscopy
Free spectroscopy reference: IR correlation table (4000-400 cm-1), 1H NMR and 13C NMR chemical shifts, mass spectrometry fragment ions, UV-Vis chromophores.
Molecular Structure Editor — 3D Viewer + 2D Editor
Free molecular structure tools: 3Dmol.js 3D viewer, 2D structure editor, 30+ preset molecules with SMILES support.
Chemistry Thermo
Thermochemistry calculator: specific heat (q=mcΔT), Hess's law, enthalpy of formation, bond energy, Gibbs free energy (ΔG=ΔH-TΔS), entropy calculation.
Biology Calculators
Free biochemistry calculators: molecular weight (DNA/RNA/Protein), mass-to-moles conversion, A260 concentration, C1V1 dilution, copy number, protein extinction coefficient, buffer recipes, and unit…
Biology Enzymes
Free restriction enzyme analysis tools: single and double digest, fragment analysis, 60+ enzyme database with search, and restriction site finder supporting IUPAC ambiguity codes.
Biology Genetics
Free genetics calculator tools: Punnett square for monohybrid/dihybrid crosses, Hardy-Weinberg equilibrium, chi-square goodness-of-fit test, gene mapping with Haldane/Kosambi functions, population…
Biology Primers
Free online primer design and analysis tools: melting temperature (Basic, Salt-Adjusted, SantaLucia), GC clamp analysis, self-dimer and hetero-dimer detection, hairpin prediction, and primer pair…
Biology Sequences
Free DNA and protein sequence analysis tools: reverse complement, transcription, 6-frame translation, GC content, melting temperature, molecular weight, and codon usage frequency.
Human Blood
Free blood & genetics calculators: ABO+Rh blood type inheritance, Widmark blood alcohol, blood pressure classification, anion gap, plasma osmolality, corrected calcium and sodium.
Human Body Metrics
Free body metrics calculators: BMI (WHO+China), BMR (3 formulas), TDEE, body fat % (Navy), ideal weight (4 formulas), waist-hip ratio, body surface area, lean body mass, frame size.
Human Clinical
Free clinical medicine calculators: eGFR (CKD-EPI/MDRD/Cockcroft-Gault), CHA₂DS₂-VASc, HAS-BLED, GCS coma scale, APGAR, Wells DVT/PE, CURB-65, Child-Pugh, MELD-Na.
Human Fitness
Free fitness calculators: maximum heart rate (5 formulas), target heart rate zones, VO2 Max, one rep max (5 formulas), running pace, activity calories, step conversion.
Human Nutrition
Free nutrition & diet calculators: macronutrient split, protein requirements, daily water intake, calorie deficit, weight loss timeline, daily calorie targets.
Human Reproduction
Free reproductive health calculators: due date by Naegele's rule, ovulation & fertile window, pregnancy week calculator, fetal weight (Hadlock), conception date, safe period estimation.
Human Tcm
Free TCM & wellness tools: nine body constitution identification, China BMI standard, sleep cycle calculator, caffeine metabolism, life expectancy estimate, and child height prediction.