Is it free?
Yes, every tool, without an account, a trial or a paywall.
Check your answers, draw your structures, finish the lab report
Free tools that show their working: balance an equation, find the limiting reagent, work out a pH, draw a structure for a report or predict its NMR spectrum. No sign-up, in any browser.
Homework and exam practice
Equation balancerBalance any equation, including ions and redox half-reactions, with exact whole-number coefficients.
Molar massMolar mass, exact mass and percentage composition for any formula or structure.
StoichiometryEnter what you have and see the limiting reagent, the theoretical yield and the excess.
Solutions and dilutionsConcentrations, what to weigh for a molar solution and how far to dilute a stock.
pH and bufferspH of acids, bases and buffers from exact equilibria, including polyprotic acids and mixtures.
Periodic tableMasses, electron configurations, electronegativity and physical data for all 118 elements.
Lab reports
Structures and schemesDraw structures and reaction schemes that snap to real bond angles, and export PNG, SVG or PDF for the report.
Reagent tablePaste your reagents and get molar masses, physical data, pKa and GHS hazards in one table to copy.
Scale the procedureFix the amount of one reagent; masses, volumes and moles for the rest follow from equivalents and density.
Compound dataMelting and boiling points, density, identifiers and hazards for over 48,000 compounds.
Organic chemistry and spectroscopy
NMR predictionEstimate 1H and 13C shifts and multiplicities from a structure to check an assignment.
Open your spectraOpen the JCAMP-DX, SPC or CSV files from the lab's spectrometer, pick peaks and integrate.
Named reactionsNamed reactions with conditions and worked procedures you can scale.
SMILES to structureTurn a SMILES string into a skeletal formula and a 3D model.
Questions students ask
Can I trust the numbers?
Each calculator shows the values it used, so you can follow the working. The chemistry behind them is checked against RDKit, NIST and PubChem reference values. Round the way your course asks you to.
Does it work on a phone?
The calculators and the compound pages do. Drawing structures is easier on a tablet or a computer.
Can I use the drawings in my report?
Yes. Export PNG, SVG or PDF from Covalent and put them in your report or slides.