Science & engineering calculators

Physics, chemistry and electronics: motion, energy, gases, solutions, circuits and batteries.

• Acceleration CalculatorCalculate acceleration from a change in speed over time, and the distance covered while speeding up, in metric or imperial units.
• Amps to Watts CalculatorConvert amps to watts for DC, single-phase AC and three-phase AC circuits, including the power factor.
• Battery Life CalculatorEstimate how long a battery will last from its capacity in mAh or Wh and the device’s current draw, allowing for real-world losses.
• Beer–Lambert Law CalculatorUse A = εlc to find absorbance, concentration or the molar absorptivity, and convert absorbance to percent transmittance.
• Boiling Point at Altitude CalculatorFind the temperature water boils at your elevation, and the air pressure there, for cooking, canning and brewing.
• Buffer pH CalculatorCalculate the pH of a buffer with the Henderson–Hasselbalch equation from the pKa and the base and acid concentrations, or the ratio needed for a target pH.
• Centripetal Force CalculatorCalculate centripetal force and acceleration for an object moving in a circle from its mass, speed and radius.
• Decibel CalculatorAdd sound levels in decibels, or find how loud a sound is at a different distance from its source.
• Density CalculatorDensity from mass and volume.
• Dilution Calculator (C1V1 = C2V2)Solve the dilution equation C1V1 = C2V2 for any one value: how much stock solution to use, or the final concentration or volume.
• E = mc² CalculatorConvert mass to energy using E = mc².
• Escape Velocity CalculatorCalculate the escape velocity from Earth, the Moon, Mars or any planet or star, from its mass and radius.
• Force Calculator (F = ma)Calculate force from mass and acceleration with Newton’s second law, F = ma, in newtons and pounds-force.
• Free Fall CalculatorCalculate how long it takes an object to fall from a height and how fast it’s going when it lands, ignoring air resistance.
• Grams to Moles CalculatorConvert grams to moles, or moles to grams, from a chemical formula, with the molar mass and number of molecules.
• Gravitational Force CalculatorCalculate the gravitational pull between two masses with Newton’s law of universal gravitation.
• Half-Life CalculatorHalf-life decay (exponential).
• Ideal Gas Law Calculator (PV = nRT)Solve the ideal gas law PV = nRT for pressure, volume, moles or temperature, in kPa, liters, moles and kelvin.
• Kinetic Energy CalculatorCalculate kinetic energy from mass and speed (KE = ½mv²) in joules, kilojoules and foot-pounds.
• LED Resistor CalculatorFind the current-limiting resistor for an LED from the supply voltage, LED forward voltage and current, with the nearest standard value and power rating.
• Molarity CalculatorMolarity (M = mol/L).
• Molecular Weight CalculatorMolecular weight from formula.
• Momentum CalculatorCalculate momentum (p = mv) from mass and velocity, or the velocity of a mass with a given momentum.
• Ohms Law CalculatorV = I × R.
• Percent Yield CalculatorCalculate the percent yield of a chemical reaction from the actual and theoretical yield.
• pH CalculatorCalculate pH and pOH from the hydrogen ion concentration, or find the [H⁺] and [OH⁻] concentrations from a pH, at 25 °C.
• Potential Energy CalculatorCalculate gravitational potential energy from mass and height (PE = mgh), on Earth or with your own value of g.
• Projectile Motion CalculatorCalculate how far, how high and how long a projectile flies from its launch speed, angle and height, ignoring air resistance.
• RC Time Constant CalculatorCalculate the RC time constant, charge time and cutoff frequency of a resistor-capacitor circuit.
• Relative Humidity CalculatorCalculate relative humidity from the air temperature and dew point, or from dry-bulb and wet-bulb thermometer readings.
• Resistor CalculatorResistor color codes and series/parallel.
• Resistors in Series and Parallel CalculatorCombine any number of resistors, capacitors or inductors in series or in parallel and get the total value.
• Specific Heat CalculatorUse Q = mcΔT to find the heat needed to warm or cool a material, or the temperature change from a given amount of heat.
• Speed of Sound CalculatorFind the speed of sound in air at any temperature, and how far away lightning is from the seconds between the flash and the thunder.
• Speed, Distance and Time CalculatorSolve for speed, distance or travel time when you know the other two, in miles or kilometers, with the pace too.
• Time Dilation CalculatorSee how much time slows for a fast-moving traveler under special relativity, from the speed as a fraction of light speed.
• Torque CalculatorCalculate torque from force and lever arm length, at any angle, in newton-meters and pound-feet.
• Voltage Divider CalculatorCalculate the output voltage of a two-resistor voltage divider, the current through it and the power each resistor burns.
• Voltage Drop CalculatorVoltage drop in wire (DC).
• Watts to Amps CalculatorConvert watts to amps for DC, single-phase AC and three-phase AC circuits, with the power factor, to size breakers and wires.
• Wavelength to Frequency CalculatorConvert between wavelength and frequency for light, radio and sound waves, and find a photon’s energy.
• Work and Power CalculatorCalculate the work done by a force over a distance, and the power when it happens over a given time.