Science & Engineering Calculators
Ohm's law, force, energy, projectile, molar mass, dilution, half-life and resistor calculators for students and engineers. Instant, accurate and 100% in your browser.
50 free tools
Ohm's Law Calculator
Solve Ohm's law online: enter any two of voltage, current, resistance or power and get the other two instantly, with mV, mA, kΩ and kW unit prefixes.
Resistor Color Code Calculator
Decode 3, 4, 5 and 6-band resistor color codes to resistance and tolerance, or convert a resistance value back into band colors. Free and instant.
LED Resistor Calculator
Calculate the series resistor for any LED from supply voltage, forward voltage and current. Get the nearest E12/E24 standard value and required wattage.
Parallel & Series Resistor Calculator
Calculate total resistance of resistors in parallel or series with unlimited values. Also works for capacitors, where the series/parallel rules invert.
Voltage Divider Calculator
Solve the voltage divider equation Vout = Vin·R2/(R1+R2) for output voltage or a missing resistor, with divider current, power and loaded-output mode.
Wire Gauge (AWG) Calculator
Look up AWG wire sizes 4/0 to 40 — diameter, cross-section and ohms per 1000 ft — and calculate voltage drop for copper or aluminium runs.
Force Calculator
Solve Newton's second law F = ma for force, mass or acceleration, plus weight W = mg on Earth, Moon and Mars, with newtons and pounds-force output.
Acceleration Calculator
Solve the SUVAT kinematic equations online. Enter any three of displacement, initial and final velocity, acceleration and time to find the other two.
Kinetic Energy Calculator
Calculate kinetic energy from mass and velocity with KE = ½mv², or solve for mass or speed. Results in joules, kilojoules, calories and foot-pounds.
Potential Energy Calculator
Calculate gravitational potential energy PE = mgh or elastic spring energy ½kx², solving for any variable, with gravity presets and unit conversion.
Momentum Calculator
Calculate momentum p = mv, impulse J = FΔt, and solve 1D elastic or perfectly inelastic collisions from conservation of momentum, all in your browser.
Projectile Motion Calculator
Compute time of flight, maximum height, range and impact velocity for a projectile, and see the trajectory plotted on an interactive canvas graph.
Molar Mass Calculator
Work out the molar mass of any chemical formula in g/mol, with a per-element breakdown. Handles brackets, hydrates and a grams-to-moles converter.
Molarity Calculator
Solve M = mol/L for molarity, moles, volume or mass of solute. Enter grams with a molar mass or a chemical formula and get the concentration instantly.
Dilution Calculator
Solve C1V1 = C2V2 for any missing term and see how much solvent to add. Works in molarity, percent, ppm and mg/mL with metric and US volumes.
pH Calculator
Convert between pH, pOH, [H+] and [OH-], or find the pH of a weak acid or base from its Ka, Kb and concentration. Shows every step of the working.
Percent Yield Calculator
Calculate percent yield from actual and theoretical yield, or solve for either one. Includes a grams-to-moles helper and an explanation of yields over 100%.
Percent Composition Calculator
Find the mass percent of every element in a chemical formula. Enter a compound and get the full composition table plus grams per element in any sample size.
Chemical Equation Balancer
Balance any chemical equation automatically. Enter reactants and products and get the smallest whole-number coefficients plus an atom-by-atom check.
Ideal Gas Law Calculator
Solve PV = nRT for pressure, volume, moles or temperature, plus combined, Boyle's and Charles's law modes with atm, kPa, bar, psi and mmHg units.
Half Life Calculator
Solve N = N0(1/2)^(t/t½) for remaining amount, elapsed time, half-life or starting amount, with decay constant, mean lifetime and isotope presets.
Density Calculator
Solve density = mass / volume for any variable in g/cm³, kg/m³ or lb/ft³, with specific gravity and a reference table of common material densities.
Interactive Periodic Table
Explore all 118 elements in the standard layout. Click any element for its atomic weight, group, period, block, electron configuration and state.
Punnett Square Calculator
Build monohybrid and dihybrid Punnett squares from two parent genotypes and get the genotype and phenotype ratios with percentages for every outcome.
DNA to RNA Converter
Transcribe DNA to mRNA, get the complement and reverse complement, translate codons to protein and see GC content — all in your browser.
Work and Power Calculator
Solve W = F·d·cos θ and P = W ÷ t for work, force, distance, angle, power or time, with newton, foot, joule, kWh and horsepower units built in.
Torque Calculator
Work out torque, force, lever arm or angle from τ = r·F·sin θ in N·m, lb·ft, lb·in or kgf·m, and turn torque plus rpm into shaft power.
Centripetal Force Calculator
Solve F = mv² ÷ r for force, mass, speed or radius, with speed entered directly or from a period or rpm, plus g-force and banking angle.
Friction Force Calculator
Find static and kinetic friction from f = μN on flat ground or an incline, with a surface table, a will-it-slip test and the resulting acceleration.
Hooke's Law Calculator
Solve F = kx for force, spring constant or extension, get the stored energy from U = ½kx², and combine springs in series or parallel.
Free Fall Calculator
Work out fall time, drop height or impact speed from v = √(2gh) and h = ½gt², with gravity presets for the Moon and Mars and an impact energy line.
Simple Pendulum Calculator
Find the period, length or local gravity of a simple pendulum from T = 2π√(L/g), with frequency, angular frequency and a large-amplitude correction.
Gravitational Force Calculator
Apply Newton's law of universal gravitation to find force, mass or separation, plus surface gravity and escape velocity with presets for every planet.
Elastic Collision Calculator
Work out the velocities after a head-on collision from conservation of momentum, with a restitution slider from perfectly elastic to perfectly inelastic.
Specific Heat Calculator
Solve Q = mcΔT for heat, mass, specific heat capacity or temperature change, with a 22-material table and a separate phase-change term Q = mL.
Wavelength and Frequency Calculator
Convert between wavelength and frequency using c = λf, with wave speed for vacuum, a medium, sound in air or a custom value, plus photon energy in eV.
Snell's Law Calculator
Solve n₁sin θ₁ = n₂sin θ₂ for the refracted angle or either refractive index, with a critical angle, total internal reflection warning and wave speeds.
Lens and Mirror Equation Calculator
Solve 1/f = 1/do + 1/di for focal length, object or image distance, with magnification, image height and a real, virtual, upright or inverted verdict.
Stoichiometry Calculator
Type a balanced equation, give the amount of one substance, and get moles and grams of every other reactant and product with the working shown.
Empirical Formula Calculator
Turn percent composition or measured masses into an empirical formula, then scale it to the molecular formula using the compound's molar mass.
Electron Configuration Calculator
Get the full and noble-gas electron configuration of any element or ion, with an orbital diagram, valence count and the last electron's quantum numbers.
Henderson-Hasselbalch Calculator
Work out buffer pH, pKa or the base-to-acid ratio you need, with a built-in pKa table and a warning when the buffer is working outside its useful range.
Titration Calculator
Find an unknown acid or base concentration, or the titrant volume needed, using equivalents so polyprotic acids and dibasic bases are handled correctly.
Gibbs Free Energy Calculator
Solve delta G = delta H minus T delta S for any variable, get a spontaneity verdict, the crossover temperature and the equilibrium constant both ways.
Freezing Point Depression Calculator
Calculate freezing point depression and boiling point elevation from molality, or work backwards from a measured shift to find a solute's molar mass.
PPM Calculator
Convert between ppm, ppb, mg/L, mg/kg and percent by mass with a density field, plus a molarity bridge and a C1V1 = C2V2 dilution helper.
DNA Codon Translator
Translate a DNA or mRNA sequence into protein across three or six reading frames, with start and stop codons marked and the longest ORF listed.
GC Content Calculator
Count A, C, G and T in a sequence to get GC content, AT content and the GC/AT ratio, plus primer melting temperature and a sliding-window GC profile.
Hardy-Weinberg Equilibrium Calculator
Get allele and genotype frequencies from observed counts or a known p, then test the population against Hardy-Weinberg equilibrium with a chi-square test.
555 Timer Calculator
Work out 555 astable frequency and duty cycle or monostable pulse width, and design backwards from a target frequency to E12 resistor values.