Free online science and maths tools

Browser simulations of atoms, molecules and materials for chemistry and physics teaching.

Search atomic energy levels for elements and ions.

Search spectral lines of elements and ions by wavelength.

Look up atomic weights and isotope abundances for all elements.

Look up ionization energies of atoms and ions.

Calculates photon attenuation cross sections for elements, compounds and mixtures.

Runs air parcel trajectory and dispersion models on NOAA servers.

Interactive normal curve showing probabilities, z-scores and percentiles.

Finds cumulative probabilities and values for a normal distribution.

Evaluates definite integrals between two limits.

Computes matrix operations such as inverse and determinant.

Computes density altitude from elevation, temperature and pressure.

Finds dewpoint and wet-bulb temperature from air temperature and relative humidity.

Finds relative humidity and dewpoint from dry-bulb and wet-bulb readings.

Finds relative humidity and wet-bulb temperature from air temperature and dewpoint.

Computes pressure altitude from station elevation and altimeter setting.

Converts between inches of mercury, millibars, hectopascals and other pressure units.

Converts temperature between Fahrenheit, Celsius and Kelvin.

Converts wind speed between knots, mph, km/h and m/s.

Collection of interactive physics simulations covering kinematics, forces, waves and optics.

Calculates cardiac output from heart rate and stroke volume.

Computes the equilibrium potential of an ion from its concentrations on each side of a membrane.

Draw a structure and search PubChem for matching compounds.

Aligns two protein 3D structures and reports RMSD.