Chemistry Calculators
23 tools in this collection — free, instant, and private in your browser.
Chemistry calculators handle the numerical side of stoichiometry, solution preparation, gas behaviour, and quantitative analysis. They are useful for students studying general or analytical chemistry, laboratory technicians preparing reagents, and researchers who need to double-check a quick calculation without returning to first principles every time.
Mole-based conversions form the backbone of quantitative chemistry. The Moles to Grams Calculator, Grams to Moles Calculator, and Moles to Particles Calculator implement the core molar mass relationships and Avogadro's number. The Molar Mass Calculator accepts a chemical formula and sums the atomic masses for you, removing a common source of arithmetic errors. The Percent Composition Calculator then breaks that molar mass back down into the elemental weight fractions.
Solution chemistry tools address concentration and dilution. The Molarity Calculator and Molality Calculator compute concentration in moles per litre and moles per kilogram of solvent respectively. The Dilution Calculator (C1V1 = C2V2) is indispensable for lab dilutions, and the Dilution Factor Calculator is a companion tool for serial dilution series. The Mass Percent Solution Calculator expresses concentration as a weight-to-weight percentage. The PPM Concentration Calculator is available for trace-level measurements in environmental and water analysis.
Gas law tools cover both individual laws and their combined form. The Ideal Gas Law Calculator (PV = nRT) solves for any one variable given the other three, while the Combined Gas Law Calculator handles changes between two states. The Gas Density at STP Calculator quickly converts molar mass to density at standard conditions.
Specialised tools include the Beer-Lambert Law Calculator for UV-Vis spectroscopy, the Hydronium Concentration to pH Calculator for acid-base problems, the Percent Yield Calculator for reaction efficiency, and the Atom Economy Calculator for green chemistry assessments. Always confirm that your units match before entering values, and use the Molar Mass tool first if you are working from a chemical formula.
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| Tool | What it does |
|---|---|
| Atom Economy Calculator | Calculate atom economy: (molar mass of desired product × stoichiometric coefficient) ÷ total molar mass of all reactants × 100. A green chemistry metric. For education only. |
| Beer-Lambert Law Calculator | Calculate absorbance, transmittance, concentration or path length using the Beer-Lambert law A = εcl. Enter any three values to find the fourth. |
| Combined Gas Law Calculator | Solve the combined gas law P₁V₁/T₁ = P₂V₂/T₂ for any unknown. Enter five known values (pressure in Pa, volume in m³, temperature in K) to find the sixth. |
| Dilution Calculator (C₁V₁ = C₂V₂) | Calculate stock solution dilutions using C₁V₁ = C₂V₂. Enter any three of initial concentration C₁, initial volume V₁, final concentration C₂, final volume V₂ to find the fourth. Includes solvent volume to add. |
| Dilution Factor Calculator | Calculate the dilution factor (DF = final volume ÷ aliquot volume) used in serial dilutions and sample preparation. Distinct from C₁V₁ = C₂V₂. For education only. |
| Gas Density at STP Calculator | Calculate the density of an ideal gas at STP (0 °C, 100 kPa, IUPAC 2010) and at SATP (25 °C, 100 kPa) from its molar mass. For education only. |
| Grams to Moles Calculator | Convert grams to moles by dividing mass by molar mass. Formula: moles = mass (g) ÷ molar mass (g/mol). For education only. |
| Hydronium Concentration to pH Calculator | Convert H⁺ (hydronium) concentration in mol/L to pH using pH = −log[H⁺]. Distinct from pOH-to-pH conversion. For education only. |
| Ideal Gas Law Calculator (PV = nRT) | Solve PV = nRT for any unknown. Enter three of pressure (Pa), volume (m³), moles and temperature (K) to find the fourth. Uses R = 8.314 J/mol·K. |
| Mass Percent Solution Calculator (w/w %) | Calculate the weight/weight percent (w/w %) of a solution: (mass of solute ÷ mass of solution) × 100. Distinct from w/v % which uses volume. For education only. |
| Molality Calculator | Calculate molality (mol solute per kg solvent) and estimate boiling-point elevation and freezing-point depression for aqueous solutions. For education only. |
| Molar Mass Calculator | Calculate the molar mass (molecular weight) of a compound by entering the number of atoms of each element. Supports H, C, N, O, Na, Cl, Ca, Fe, S, P, K, Mg. Result in g/mol. |
| Molarity Calculator | Calculate molarity (mol/L) from moles and volume, or from mass and molar mass. Essential for chemistry lab work. Also outputs mg/mL concentration. |
| Moles to Grams Calculator | Convert moles to grams by entering moles and molar mass. Formula: mass (g) = moles × molar mass (g/mol). For education only. |
| Moles to Particles Calculator (Avogadro's Number) | Convert moles to number of particles (atoms, molecules or ions) using Avogadro's number 6.022×10²³ mol⁻¹. For education only. |
| PPM Concentration Calculator | Calculate concentration in ppm (mg/L) and ppb (µg/L) from solute mass in milligrams and solution volume in litres. For education only. |
| Percent Composition Calculator | Calculate percent composition by mass of a compound. Enter the total contribution (atomic mass × count) for H, C, N, O and other elements. For education only. |
| Percent Yield Calculator | Calculate percent yield of a chemical reaction: (actual yield ÷ theoretical yield) × 100. Enter masses in any consistent unit (g, mg, kg). For education only. |
| Solution Concentration Calculator | Calculate solution concentration in w/v percent, g/L and ppm (mg/L). Enter solute mass in grams and solution volume in millilitres. |
| Specific Heat Calculator (Q = mcΔT) | Calculate heat energy Q = mcΔT. Enter mass (kg), specific heat capacity (J/kg·K) and temperature change (ΔT in °C or K) to get heat in Joules. |
| Theoretical Yield Calculator | Calculate the theoretical yield (maximum possible product mass) from the limiting reagent mass, molar masses and stoichiometric ratio. For education only. |
| pH Calculator | Calculate pH, pOH and OH⁻ concentration from H⁺ (hydrogen ion) concentration in mol/L. Find out if a solution is acidic, basic or neutral. |
| pOH to pH Calculator | Convert pOH to pH using the relationship pH + pOH = 14 (at 25 °C). Also shows H⁺ and OH⁻ concentrations. For education only. |
Frequently asked questions
- What is the difference between molarity and molality, and which tool should I use?
- Molarity (mol/L) expresses moles of solute per litre of solution and is the standard for most laboratory work. Molality (mol/kg) expresses moles of solute per kilogram of pure solvent and is preferred when temperature varies, because it is not affected by thermal expansion. Use the Molarity Calculator for standard bench work and the Molality Calculator for thermodynamic or colligative property calculations.
- How does the Percent Yield Calculator work?
- Enter the actual yield you obtained from your reaction and the theoretical yield calculated from stoichiometry. The calculator divides actual by theoretical and multiplies by 100 to give the percent yield. Values below 100 percent reflect losses from incomplete reaction, side products, or handling.
- Can the Ideal Gas Law Calculator handle non-standard pressures and temperatures?
- Yes. The tool accepts any consistent set of units for pressure, volume, moles, and temperature. Make sure temperature is in Kelvin (add 273.15 to Celsius values) and that your pressure and volume units match the gas constant value you select from the provided options.