Chemistry Calculators, Physics and Lab Tools
Chemistry calculators, physics calculators and molecular biology tools for the bench and the problem set.
Chemistry
- Molarity CalculatorM = n / V = m / (MW × V). Type the formula and the molarity calculator works out the molar mass, then any two of mass, volume and concentration give the third, with the lab steps to make it up.
- Dilution CalculatorC1V1 = C2V2, solved by the dilution calculator for whichever term you are missing. It also gives the diluent to add, which is the number you actually pour.
- pH CalculatorpH = -log10[H+]. The formula is one line; the work a pH calculator does is in getting [H+], which for a weak acid, a buffer or a very dilute solution is not simply the concentration on the bottle.
- Chemical Equation BalancerType the unbalanced equation into the chemical equation balancer. The coefficients come from exact linear algebra, every element is checked on both sides, and the reactant masses below turn it into a yield calculation.
- Ideal Gas Law CalculatorPV = nRT. Enter any three of pressure, volume, moles and temperature in the units you have, and the ideal gas law calculator solves for the fourth.
- Density CalculatorGive the density calculator any two of density, mass and volume and it finds the third. It also says whether the thing floats, which is density against water.
- Half-Life CalculatorN = N0 × (1/2)^(t/T). Give the half life calculator any three of the starting amount, the amount left, the time and the half-life, and it finds the fourth.
- Protein Molecular Weight CalculatorA protein's mass is the sum of its residues plus one water. The protein molecular weight calculator does the sum from Expasy's residue masses, and the extinction coefficient alongside, so a reading at 280 nm becomes a concentration.
Molecular biology
- DNA Concentration CalculatorThe DNA concentration calculator applies concentration = A260 × factor × dilution ÷ path length, with 50 for dsDNA, 33 for ssDNA and 40 for RNA. It also reads the purity ratios and works out how many molecules that is.
- Primer Tm CalculatorPaste a primer and the primer Tm calculator gives its melting temperature from the published nearest-neighbor parameters, with the enthalpy, entropy and free energy behind it and the two rough rules alongside for comparison.
- Ligation Calculatorinsert ng = ratio × vector ng × insert length ÷ vector length. The ligation calculator turns a molar ratio into the nanograms you actually pipette.
- Hemocytometer Calculatorcells/mL = cells counted ÷ squares counted × dilution × 10^4. Count, enter the dead cells, and the hemocytometer calculator gives viability and the volume to seed.
- RCF CalculatorThe RCF calculator uses RCF = 1.118 × 10^-5 × r × rpm², with r in cm. Convert a protocol's × g into the rpm your rotor needs, or a speed into g.
Physics
- Kinematics CalculatorPick the two quantities you do not know and enter the three you do; the kinematics calculator picks the one SUVAT equation that leaves the other unknown out, then shows the work.
- Speed CalculatorGive the speed calculator any two of speed, distance and time and it finds the third, in miles, kilometers, meters, feet or nautical miles, and converts the answer to every common unit.
- Force CalculatorF = ma and the six quantities built on it, in one force calculator, each with the numbers substituted and the unit algebra written out, which shows why a newton is a kilogram meter per second squared.
- Simple Harmonic Motion CalculatorPeriod and frequency for a spring or a pendulum, Hooke's law, and where an oscillator is at any moment, all in one simple harmonic motion calculator. The numbers are substituted into each formula, and the pendulum's small-angle error is measured rather than ignored.
- Wavelength CalculatorThe wavelength calculator solves v = fλ for wavelength, frequency or wave speed, and gives the energy of one photon for light and radio waves.
- Ohm's Law CalculatorGive the Ohm's law calculator any two of volts, amps, ohms and watts and it returns the other two. The formula used is shown beside every answer, so the page doubles as the wheel of twelve.
- Gear Ratio CalculatorGear ratio = driven teeth ÷ driving teeth. Enter the teeth for up to three stages and the gear ratio calculator gives the overall ratio, the output speed and the output torque.
Weather and atmosphere
- Dew Point CalculatorThe dew point is the honest measure of how much water is in the air. Give the dew point calculator a temperature and the humidity (or the dew point) and get the rest of the psychrometric picture from WMO's and the National Weather Service's own formulas.
- Altitude Pressure CalculatorAn altitude pressure calculator built on the 1976 standard atmosphere, the model behind the aviation tables, for air pressure by elevation and what that pressure does to the boiling point of water.
More categories
- Math CalculatorsMath calculators that show their work: arithmetic, algebra, statistics, and a calculus calculator for derivatives and integrals, with exact answers in fractions and radicals where they exist.
- Geometry CalculatorsGeometry calculators for shapes, lines and angles, with the formula behind each answer explained.
- Conversion CalculatorsConversion calculators for unit conversion, number bases, Roman numerals and angles. The unit converter shows the factor it used and a conversion chart for the values around yours.
- Date and Time CalculatorsDate and time calculators for counting days, adding hours, converting time zones and reading other calendars.
- Business CalculatorsBusiness calculators for pricing a product and for the unit economics behind a company: margin, markup, break-even, ROI, CAC, LTV and churn.
- Random GeneratorsRandom generators that draw fairly, from your browser's cryptographic generator: numbers, names, teams, coin flips and dice.
- Everyday Cost CalculatorsCost calculators for what a meal, a drive or an appliance actually costs: tips, split bills, fuel, electricity and EV charging.
- Free Online ToolsFree online tools for codes and text, run in your browser with nothing uploaded.