Chemistry Calculators
A growing set of free chemistry tools for students, TAs and lab work — concentration, solutions, gas laws, acids and buffers, and reaction yields. Each shows the formula, a worked example and the assumptions behind the result.
Concentration & solutions
Molarity Calculator
Molality Calculator New
Normality Calculator New
Dilution Calculator New
Mass Percent Calculator New
Moles & mass
Acids, bases & gases
Built for coursework and the lab bench
These tools cover the calculations that come up again and again in general and analytical chemistry: preparing a solution to a target concentration, diluting a stock, converting between grams and moles, predicting a buffer's pH, applying PV = nRT, and reporting a reaction's percent yield. Every calculator states the equation it uses and works a numeric example, so you can check the method as well as the answer.
Frequently asked questions
Which concentration unit should I use?
Use molarity (mol/L) for volumetric work, molality (mol/kg) for temperature-independent and colligative-property problems, normality for titrations, and mass percent for labels and recipes.
Are these calculators accurate enough for lab reports?
They apply the standard textbook formulas and constants (for example R = 0.08206 L·atm/mol·K and Kw = 1.0×10⁻¹⁴ at 25 °C). Always confirm against your course's required significant figures and conditions.
Do the gas and pH tools assume a temperature?
Yes — the ideal gas law uses R for atm/L/K, and pH relations assume 25 °C where Kw = 1.0×10⁻¹⁴. Both change with temperature.