Free Online Calculators for Chemistry, Math & Science

Calculate the bond order of a molecule using molecular orbital theory. Enter the number of bonding and antibonding electrons to determine bond order, bond strength, and bond stability with step-by-step solutions.

Determine the full electron configuration and noble gas shorthand notation for any element. Enter an atomic number (1-118) to see orbital filling using the aufbau principle, with exceptions for chromium, copper, and other irregular elements.

Calculate the Mulliken electronegativity of an element from its ionization energy and electron affinity, with automatic conversion to the Pauling scale. Understand how strongly an atom attracts bonding electrons.

Calculate pKa from Ka or Ka from pKa instantly. Convert between acid dissociation constant (Ka) and its negative logarithm (pKa) with step-by-step solutions. Free online chemistry tool.

Calculate the percent composition by mass of each element in a chemical compound. Enter any chemical formula to get a detailed breakdown of mass percentages with step-by-step calculations.

Calculate the percent ionic character of a chemical bond using the electronegativity difference between two atoms. Uses the Pauling formula to determine how ionic or covalent a bond is.

Calculate the average atomic mass of an element from its isotope masses and natural abundances. Supports up to 4 isotopes.

Calculate the effective nuclear charge (Z_eff) experienced by an electron using Slater's rules. Enter an atomic number to determine the shielding constant and the net positive charge felt by the outermost electron.

Look up the atomic mass of any element by its atomic number. Get the standard atomic weight in atomic mass units (amu) along with element details.

Calculate the molar mass of any chemical compound. Enter a chemical formula like H2O, NaCl, or Ca(OH)2 to get the molecular weight in g/mol with a step-by-step breakdown.

Find the number of protons, neutrons, and electrons for any element. Enter an atomic number (1–118) and optional charge to get a complete breakdown of atomic structure.

Estimate your AP Chemistry exam score. Enter your multiple choice and free response scores to predict your AP score on the 1-5 scale.