Science calculators
Science problems tend to go wrong in the units rather than in the formula. These calculators accept the units you have, convert them consistently, and apply the standard equation for motion, electricity, gases, solutions, genetics, and more.
Every tool names the idealizations behind its formula, such as an ideal gas, a frictionless surface, or a dilute solution, so you know how far the answer can be trusted for a real system.
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- Density CalculatorSolve for density, mass or volume from the other two, in kg/m³, g/cm³ or lb/ft³.
- Molar Mass CalculatorType a chemical formula to get its molar mass in grams per mole, with each element's atom count, share of the mass and mass percent.
- Molarity CalculatorFind a solution's concentration, or how many grams to weigh out to make one, with lab units like mL and mM converted for you.
- Moon Phase CalculatorSee the moon's phase on any date from 1800 to 2200: how much of it is lit, how old it is, and when the next full and new moons come.
- Ohm's Law CalculatorKnow two of voltage, current, resistance and power? Enter them, and this finds the other two for you.
- Velocity CalculatorFind average velocity from displacement and time, solve for the displacement or time instead, or get final velocity from v = u + at.
- Acceleration CalculatorWork out acceleration from a change in speed, from force and mass, or from distance travelled, and solve any of those formulas for the missing value.
- Angular Momentum CalculatorFind the angular momentum of a spinning object from its moment of inertia and spin rate, a common shape's mass and size, or a mass on a circle.
- Angular Velocity CalculatorFind how fast something turns from an angle and a time, a speed and radius, or a frequency or period. Get rad/s, degrees per second or rpm.
- Bacteria Growth CalculatorModel exponential (steady doubling) growth with N = N₀·2^(t/g). Solve for the final count, the time needed or the doubling time.
- Battery Life CalculatorSee how long a battery will run your device, from its capacity (mAh, Ah or Wh) and the device's draw (mA, A or W). Also converts mAh to Wh.
- Blood Type Inheritance CalculatorSee the possible ABO and Rh blood types of a child, and the chance of each, from both parents' blood types.
- Boyle's Law CalculatorSolve Boyle's law, P₁V₁ = P₂V₂, for the pressure or volume of a gas compressed or expanded at constant temperature.
- Buoyancy CalculatorFind the upward push a liquid or gas gives a submerged object, or check whether an object floats and how much of it sits below the surface.
- Capacitor CalculatorFind the total value of capacitors wired in parallel or series, then the charge and energy they store at a given voltage.
- Carbon Dating CalculatorEstimate the age of organic material from the percent of carbon-14 it still contains, in both physical years and conventional radiocarbon years.
- Carrying Capacity CalculatorSee how a population grows and levels off at the most its home can support: find the population at any time, or the time to reach a target.
- Centripetal Force CalculatorFind the inward (centripetal) force and acceleration for something moving in a circle, from mass, speed or spin rate, and radius, or solve for any of them.
- Charles's Law CalculatorSolve Charles's law, V₁/T₁ = V₂/T₂, to find a gas's volume or temperature when the pressure stays the same. Temperatures are converted to kelvins for you.
- Chemical Equation Balancer CalculatorBalance a chemical equation with the smallest whole numbers that work, found by exact math, and see the atom-by-atom check.
- Combined Gas Law CalculatorFind the missing pressure, volume or temperature when a gas changes from one state to another, by solving P₁V₁/T₁ = P₂V₂/T₂.
- Coulomb's Law CalculatorFind the electric force between two point charges. Or solve Coulomb's law for the distance or one of the charges.
- Dilution CalculatorPlan a dilution with C1V1 = C2V2. Solve for the stock volume, stock concentration, final concentration or final volume, even in mixed units.
- Doppler Effect CalculatorFind the frequency heard from a moving source, a moving observer, or both, with a clear choice of sign convention.
- Drag Equation CalculatorWork out the drag force, how hard air or water pushes back on a moving object, from density, speed, shape and area. Or solve for any of them.
- E = mc² CalculatorSee how much energy a given mass is worth, or how much mass an amount of energy equals, with Einstein's mass–energy relation E = mc².
- Elastic Collision CalculatorFind how fast two objects move after a head-on crash, whether they bounce apart, stick together or land in between, using conservation of momentum.
- Electrical Power CalculatorConvert between watts, amps, volts and kVA for DC, single-phase AC and three-phase AC circuits.
- Electron Configuration CalculatorWrite out where the electrons sit in any element or ion (its ground-state configuration), with noble-gas shorthand, outer-shell and unpaired electrons.
- Empirical Formula CalculatorTurn the element masses or percentages of a compound into its simplest whole-number formula, and its molecular formula from the molar mass.
- Escape Velocity CalculatorFind the speed needed to escape the gravity of Earth, the Moon, Mars, Jupiter, the Sun or any body you describe by its mass and radius.
- Force CalculatorFind a force, a mass or an acceleration from the other two, using F = ma (force equals mass times acceleration), in metric or US units.
- Free Fall CalculatorFind how long something takes to fall from a height and how fast it hits the ground. You can also see how far it has fallen at any moment, ignoring air resistance.
- Friction CalculatorFind the friction force F = μN, the coefficient of friction or the normal force, on level ground or on a slope.
- G-Force CalculatorFind how many g's an acceleration is, from a speed change over time, a stopping distance, a turn radius or an acceleration you already know.
- Gear Ratio CalculatorFind the gear ratio, output speed and output torque of a gear pair or a two-stage compound gear train from tooth counts.
- Grams to Moles CalculatorSwitch between grams, moles and number of particles, using a chemical formula or a molar mass you enter. Avogadro's number is built in.
- Gravitational Force CalculatorApply Newton's law of universal gravitation, F = G·m₁·m₂/r², to find the force between two masses, one of the masses, or their distance.
- Half-Life CalculatorFind the amount left, the time elapsed, the half-life or the starting amount of a decaying substance, plus its decay constant.
- Hardy-Weinberg CalculatorFind how common each version of a gene is (p and q) and the expected genotype shares p², 2pq and q², with an optional chi-square test.
- Henderson–Hasselbalch CalculatorFind the pH of a buffer from its pKa and concentrations. Or find the base-to-acid ratio and amounts that reach a target pH.
- Hooke's Law CalculatorUse Hooke's law, F = kx, to find a spring's force, stiffness or stretch, plus the energy it stores when stretched (its elastic potential energy, ½kx²).
- Ideal Gas Law CalculatorSolve PV = nRT for a gas's pressure, volume, moles or temperature. Units are converted for you, and temperatures are checked against absolute zero.
- Kinetic Energy CalculatorFind the kinetic energy of a moving object from its mass and speed, or solve for the mass or speed instead.
- LED Resistor CalculatorFind the resistor that keeps one LED or a string of LEDs at a safe current, with the nearest standard value, its heat and a safe rating.
- Molality CalculatorFind molality (moles of dissolved substance per kilogram of liquid), or how much of either you need for a target molality.
- Momentum CalculatorFind how much motion an object carries (its momentum) from its mass and velocity. Or solve for mass, velocity or an impulse.
- Partial Pressure CalculatorFind how much of a gas mixture's pressure comes from one gas, or add up each gas's pressure to get the total, using Dalton's law.
- Pendulum CalculatorFind how long a pendulum takes to swing from its length, or the length you need for a given swing time, with an optional wide-swing correction.
- Percent Composition CalculatorSee what share of a compound's weight comes from each element, or how much of a solution's weight is the dissolved substance.
- Percent Solution CalculatorFind out how much of a substance to dissolve, and how much liquid to add, for a weight/volume, weight/weight or volume/volume percent solution.
- Percent Yield CalculatorFind percent yield from actual and theoretical yield, the theoretical yield from the limiting reactant, or the actual yield from a percent.
- pH CalculatorConvert between pH, pOH, hydrogen ion concentration and hydroxide ion concentration, or find the pH of a strong acid or base from how much is dissolved.
- Potential Energy CalculatorFind the energy an object stores by being lifted (PE = mgh) on Earth, the Moon, Mars or any gravity. Or solve for the mass, height or g.
- Power Factor CalculatorFind the power factor, the three kinds of power (real, reactive and apparent), the phase angle, and the capacitor size (kVAR) needed to correct it.
- Projectile Motion CalculatorFind a projectile's range, time of flight, maximum height and impact speed and angle from its launch speed, angle and height, with a table of positions.
- Punnett Square CalculatorBuild a Punnett square for one gene or two genes from two parents' genotypes. See the genotype and phenotype ratios of their offspring.
- RC Time Constant CalculatorSee how fast a capacitor charges or empties through a resistor: its voltage at any moment, or how long it takes to reach a voltage.
- Resistor CalculatorFind the total resistance of resistors wired in series or parallel, plus the current, voltage and power for each one.
- Resistor Color Code CalculatorRead 4-, 5- and 6-band resistor colors as a resistance, tolerance range and temperature coefficient, or find the bands for a value.
- Snell's Law CalculatorFind how much light bends between two materials: solve n₁ sin θ₁ = n₂ sin θ₂ for either angle or either index, with the critical angle.
- Specific Heat CalculatorFind how much heat it takes to warm something (Q = m × c × ΔT), or solve for mass, specific heat or temperature change, with typical material values.
- Speed of Sound CalculatorFind how fast sound travels in dry air from its temperature, or in any ideal gas from γ, molar mass and temperature.
- Stoichiometry CalculatorStart from the amount of one substance in a reaction and see how much of every other one reacts or forms, and which runs out first.
- Sunrise and Sunset CalculatorFind sunrise, sunset, solar noon, day length and twilight times for any place on Earth (by latitude and longitude) on any date.
- Thermal Expansion CalculatorSee how much a beam, pipe or tank of liquid grows or shrinks when it warms or cools, with typical values for common materials.
- Torque CalculatorFind torque from a force applied at a distance and angle, τ = r·F·sin θ, or solve for the force, lever arm or angle.
- Voltage Divider CalculatorFind the output voltage of a two-resistor voltage divider, or the R1 or R2 you need for a target voltage. You can include a load, too.
- Wave Speed, Frequency and Wavelength CalculatorFind a wave's wavelength, frequency or speed from the other two (v = f × λ), with the period and presets for light and sound.
- Work and Power CalculatorFind the work a force does when it moves something, W = F·d·cos θ, and the power, P = W ÷ t. Or solve for any other value.