Free Science & Engineering Calculators
Free science and engineering calculators for the formulas students and makers reach for most. Solve Ohm's law for voltage, current, resistance, and power; work with gases using the ideal gas law (PV = nRT) and the combined gas law (which contains Boyle's, Charles's, and Gay-Lussac's laws); and convert pressure and energy units. Every tool shows the exact formula, the units it expects, and worked examples, and runs entirely in your browser. These are educational tools — always double-check safety-critical engineering work against authoritative references and standards.
The combined gas law relates the pressure, volume, and absolute temperature of a fixed amount of gas between two states. It states that the quantity PV/T stays constant when the amount of gas does not change, which is written P1·V1/T1 = P2·V2/T2. Enter any five of the six values (two pressures, two volumes, two temperatures) and this calculator solves for the sixth. Temperatures must be entered on the Kelvin (absolute) scale; a value in Celsius is converted with K = °C + 273.15. Pressure and volume may use any units, provided you use the same unit for both states.
This Ideal Gas Law Calculator solves the equation PV = nRT for any one unknown quantity — pressure (P), volume (V), amount of substance (n), or temperature (T) — when you supply the other three. The ideal gas law links the four state variables of a gas through a single proportionality constant, the universal gas constant R, and gives a remarkably good description of real gases at low pressures and moderate-to-high temperatures. Enter your known values in consistent SI units and the calculator rearranges the equation to return the missing one, so you do not have to do the algebra or unit-tracking by hand.
This Ohm's Law calculator solves for voltage, current, resistance and power in a simple DC circuit. Enter any two of the three core quantities, voltage (V), current (I) or resistance (R), and the calculator computes the missing value along with the electrical power (P). Ohm's Law is one of the most fundamental relationships in electronics: it describes how voltage, current and resistance interact in a conductor, and it underpins almost every circuit calculation you will encounter when working with batteries, resistors, LEDs, motors and power supplies.
A full scientific calculator in your browser — trigonometry, logarithms, exponents, roots, factorials, constants, and memory, with degree, radian, and gradian modes.