Science Calculators
Chemistry and physics calculators built to a lab standard: IUPAC atomic weights with their published uncertainties, exact SI constants, and every result honest about how many of its digits actually mean anything.
Chemistry 6
- Molar Mass CalculatorMolar mass and percent composition from any formula, with honest digits.
- Molarity CalculatorMolarity, molality, normality and percent, solved from your formula.
- Dilution CalculatorC1V1 = C2V2 with the recipe, plus serial dilutions done honestly.
- Percent Yield CalculatorPercent yield, plus the limiting reactant that sets the ceiling.
- Gas Law CalculatorAll six gas laws, with the work shown and the kelvin trap priced.
- Half-Life CalculatorDecay in both directions, 13 isotopes, and honest radiocarbon dating.
Motion & Forces 7
- Velocity CalculatorSolve v = d/t for speed, distance, or time, in any units.
- Acceleration CalculatorAll five kinematics quantities from any three, plus the answer in g.
- Force CalculatorF = ma solved any way, plus what you weigh on every planet.
- Momentum CalculatorMomentum, impact force, and why crumple zones work.
- Kinetic Energy CalculatorKinetic and potential energy, and why double the speed is four times the energy.
- Projectile Motion CalculatorFull projectile flight, and the best angle for your launch height.
- Torque CalculatorTorque from force and lever, plus the wrench adapter correction.
Waves & Measurement 2
More tools 4
- Coordinates ConverterPaste any GPS format, get all three, with 4,000 year old arithmetic shown.
- Ohms Law CalculatorThe full power wheel: any two of volts, amps, ohms and watts.
- Radians to Degrees CalculatorRadians to degrees and back, exact when you type pi, with the working shown.
- RPM CalculatorEngine rpm from your gears and tyres, or pulley speeds.
What lives here
Chemistry and physics, built to a standard that would survive being used in front of a class. Every atomic weight on these pages comes from the IUPAC published table with its uncertainty attached, every physical constant is the exact post-2019 SI value where one exists, and every worked example was executed against the page's own code before it was written down rather than copied from somewhere else.
Two habits run through all of them. The first is honesty about precision: the molar mass calculator tells you how many of its digits the published uncertainties actually support, the projectile page says out loud that ignoring air resistance makes its answer an upper bound rather than a forecast, and the significant figures page refuses to give a single number for something like 4500 because plain decimal notation genuinely cannot say. The second is that every page has one thing worth knowing that a homework helper will not tell you.
The findings, if you only read one page
A few of the things these calculators exist to say. IUPAC no longer publishes a single atomic weight for fourteen elements, because natural isotopic variation is larger than anyone's measurement error; lead is the extreme case at [206.14, 207.94], since it sits at the end of three decay chains and carries the uranium history of whatever ore it came from. Radiocarbon laboratories still report ages on a half-life that has been known to be wrong since 1962, deliberately, so that seventy years of published dates stay comparable, and calibration cancels the error anyway. 45 degrees is only the best throwing angle from ground level, which is why shot putters release below it. And a torque wrench with an in-line adapter over-torques the bolt by a percentage nobody applies, while still clicking exactly when it should.
Where the boundaries are
These pages are careful about what they are not. A model that stops being true gets told on: the ideal gas law flags high pressures where real gases drift from it, the kinetic energy page names the 10% of light speed where the classical formula starts under-reporting, and the half-life page stays out of drug dosing entirely, because that belongs on a health page with the disclaimers a health page carries.
The nearest neighbours are worth knowing about too. Unit conversions live in Unit Conversions, the pure algebra and calculus tools in Math, and the applied technology calculators, EVs and data centres and spaceflight, in Tech and Innovation.