Online Chemistry Calculators

Overview

Chemistry is the science of matter: its composition, its properties, the changes that lead to its formation, and the ways it interacts with other matter in its surroundings. We start with the building blocks of matter - electrons, neutrons, and protons - and build atoms and ions, which then form the molecules and ionic compounds that can react to produce the material world we know. Careful investigation of the properties and tendencies of these material formations promotes better understanding of the capabilities of the material world.

This collection of chemistry calculators, broken down into different fundamental concepts, is a good survey of introductory chemistry, but also contains some tools for higher level endeavors in such topics as quantum numbers and advanced stoichiometry.

Acid-Base Reactions

WebQC pH calculator - Need to know the pKa of a solution? Or maybe even just the pH? Check out this page for all your acid-base reaction needs.
EasyCalculation Neutralization Reaction - There are two ways of checking your work: turning it in and hoping for the best, or using this site. It's as easy as click, plug, and check!
Meracalculator Neutralization Reactions - Great when working on neutralization reactions of acids and bases, get back to “normality” with this easy to use problem solver.

Buffers

PFG Buffer Recipes - This simple tool delivers fast and accurate answers, along with the option to print out your results and buffer recipe for future reference.
Wiley Buffers - Very simple, ad-free site for buffer calculation.
Science Gateway Common Reagents & Buffers - Need to know a buffers' mass or volume? How about the volume of buffer necessary to dilute a solution? Click here also to see a list of common reagents.

Catalysis

Activation Energy - Need to know a reaction's activation energy in J/mol instead of Btu/lb mol? Just plug and chug your activation energy answers here for fast and convenient computations.

Chemical Equilibrium

Onlinesciencetools Chemical Equilibrium - Tip the scales in the right direction with this easy to use equilibrium balance. Simply insert your figures into the spaces provided and your formulas will always even out.
Tutorvista Equilibrium Constant - Find the equilibrium constant for any equation with this easy to use online equation. Simply input your equilibrium values and click “calculate equilibrium constant.”
Colorado State Equilibria - A more advanced, precise online source for tallying equilibria.

Empirical and Molecular Formulas

Chemicalaid Empirical Formulas - Perfect when you need to know the empirical formula of an equation and need the molecular formula, or vice versa.
Easycalculation Chemical Formulas - Click here for simple and efficient calculations for the percentage of each element in a given compound.
Empirical and Molecular Formula Solver - Want to make sure all your empirical and molecular ducks are in a row? Simply follow the easy instructions on mmsphyschem.com and you'll master this aspect of chemistry in no time.
University of Sydney Empirical Formula Calculator - Enter your empirical formulas here and get back the percentage of mass for each element involved.

Electrochemistry

Electrical Driving Force Calculator - Find the driving force behind any electrochemical reaction with this easy-to-use tool.
Calctool.org Nernst Solver - Need to know the actual or standard reversible potential of a Nernst equation? Enter your data into the text boxes and start getting some answers.
TutorVista Nernst Equation - Find an equation's reduction potential using this simple Nernst equation. Fill in the allotted text boxes with your figures and let it do the rest.

Electrolysis

Convert Coulombs to Faraday Constants - Struggling with converting coulombs to Faraday constants? Start your conversions now.

Electron Quantum Numbers

Chem.purdue.edu Quantum Numbers and Electron Configuration - Need to see electron quantum numbers explained a different way? This is a great place to start the understanding and mastery process of quantum numbers.
Angelo.edu Quantum Numbers, Atomic Orbitals, and Electron Configurations - Didn't quite catch onto electron configurations in class? Here you'll find plenty of examples and explanations of quantum numbers.

Gas Laws (Ideal, Dalton's and Graham's Law)

AJ Design Ideal Gas Law Formulas and Equations - Whether you're solving for density, pressure, temperature or volume using the Ideal gas law,
WebQC Ideal Gas Law - An ideal place for any chemist, student, or otherwise to have quick access to multiple equations and easy-to-use calculation.
EasyCalculation Ideal Gas Law - Simply plug in the figures you know from your Ideal gas law equations and let easycalculation.com do the rest.
Mera Calculator Dalton's Law - If you need to know the partial pressures of an equation then meracalculator.com is the right fit for you. This site uses Dalton's Law to compute those partial pressure values for you.
1728 Graham's Law of Diffusion - This is a great place to go for Graham's law of diffusion equations. User-friendly, accurate results.

Ionic/Covalent Bonds

Chemical Bond Polarity – Perfect for identifying the bond polarity between two elements.

Ions and Molecules

Digital Ionic Equation - Know the name of a molecule but not what it's made of? Simply type in the name and this tool will provide you with the molar mass and empirical formula of the molecule.
Shodor Polyatomic Ion - If you know the empirical formula of an ion or molecule, then you can know its name. Great for if you're new to ion and molecules or if you just want to double-check your work.
Mera Calculator Polyatomic Ion - Simple yet effective, this calculator allows you to input the positive and negative ions from an empirical formula and it then spits out the molecule's name.

Kinetics

AJ Design Kinetic Energy Equations and Formulas - Got kinetic energy equations and numeric values with nowhere to compute them? Derive kinetic energy values here.
EngineersEdge Kinetic Energy Equations - Short and simple way to find the kinetic energy of an object. Plug in the equations values in the text boxes and your problems are solved.
EasyCalculation Kinetic Energy - Whether you're solving for kinetic energy or mass, just enter in your data and you'll have your answers.

Mass Spectrometry

Native Mass Spectrometry – Interchangeable calculations of m/z, charge, mass, theoretical charge states.
Isotope Distribution and Mass Spec Plotter – Provides both equations as well as plots your mass spectrometry chart for you.

Nuclear Decay

AJ Design Radioactive Material Equations and Formulas – Here you'll find detailed instructions on nuclear decay reactions and easy to use interactive equations.
UWashington Radioactive Decay - Simple and complete nuclear decay equations that provide precise answers.
Rad Pro Nuclear Calculations - Whether you're a career chemist or learning about nuclear decay for the first time, this is the perfect place to input your data and learn more.
Radioactive Isotopes Decay - Need a place for fast and easy nuclear decay equations? Here you'll find a fantastic online equation solver.
Shodor Nuclear Decay - Need to know the nuclear decay of unstable molecules? With easy data input and answers, and a brief summary of nuclear decay equations themselves.

Oxidation-Reduction Reactions

TutorVista Oxidation Number - Type in the desired chemical formula and this useful online tool spits out the oxidation-reduction number in seconds.
Shodor Redox Reactions - For a more in depth look at oxidation-reduction reactions check out this great plug and chug problem solver.
Wolfram Oxidation Number - Simply type in a chemical formula and in no time at all you will have the oxidation-reduction reaction numbers and structure diagram.

Percentage Composition

TutorVista Percent Composition - Learn the percentage composition by mass of each element in a chemical formula.
Chemhaven Percent Composition - Know the percent composition of each element in any chemical formula.

Significant Figures

Significant Figures - Don't slow down due to long handwritten equations. Plug in your equations or numbers here for fast and reliable tallies of your significant figures.
Ostermiller Significant Figures - Significant figures tripping you up? Click here and input your numbers to derive the correct amount of significant figures for any number as well as identify the least significant decimal.
Significant Digits Counter for Chemists - Want to double-check your significant figure count? Just type in your numbers for accurate and precise significant figures.
CalculatorSoup Significant Figures – With extensive details on identifying significant figures, this tool also helps teach you how to round (and can check your work).
TutorCircle Significant Figures – Extensive listing of examples and instructions on significant figures, with a sig-fig counter so you can even check your work.

Solution Concentration

Calctool Solution Concentration – Convert between mass, volume, and molecular volume to calculate molecular and/or mass concentrations.
Advamacs Concentrations – Switch between molecular weight and density, with built in sample solutions to help you study.
Easycalculation Dilution of Solutions – Identify the volumes and concentrations of a solution before and after dilution.

Solution Stoichiometry (Moles, titration, and molarity calculations)

Endmemo Chemical Mole Grams - Input chemical formulas here to figure out the number of moles or grams in a chemical formula.
AJ Design Ideal Gas Law Formulas and Equations - Use this online number cruncher to solve Ideal Gas Law equations and formulas using pressure, volume, and temperature.
Lenntech Molecular Weights – Compute the average molecular weight (MW) via molecular formula or from one of the two lists of common organic compounds or elements of the periodic table.
Stoichiometry Tool - Enter your balanced chemical equations (use the Chemical Equation Balancer if need be!) to derive the stoichiometry of each equation.
OST Stoichiometry – With a wide range of entry parameters and options for gas type as well as output, this tool is essential for your stoichiometry calculations.
Reaction Stoichiometry – Given a reaction and select whether you want to calculate the reactant or product.
Concentration of a Solution via Titration – Online tool to titrate samples given the concentration of the standard, volume of titrant needed for titration of the standard and of the sample.
GraphPad Molarity – Mass, volume, and concentration: given two, easily calculate the other, or else dilute a stock solution.
Molaritycalculator.com – Allowing you to calculate mass, volume, or concentration depending on which two are known, this page also has extensive explanations of the different ways to perform these calculations manually.
Sigma-Aldrich Mass Molarity – Calculate the mass required for a molar solution of a specified concentration and volume.

Extra Tools

List of Common Equations

Reference Guide of Common Chemistry Equations - Missing an equation in your notes or textbook? Check here for a list of commonly and frequently used equations in chemistry.

Periodic Table

Interactive Periodic Table - Need a reference while you're doing your chemistry homework, or maybe you just want to learn more about the elements? If so this interactive periodic table is perfect for the casual browser or studying for tests.

Basic Units of Measurement (Metric/SI)

UCDavis SI Units - Need to know which unit of measure to use for that density equation? Maybe you need to brush up on your measurement prefixes? Whatever the case may be, this list of SI units is a handy reference.