Chemistry Calculators and Formulas
Calculators for school and laboratory chemistry: molar mass from a formula, moles and concentration, dilutions, pH, the gas laws and radioactive decay, plus converters for clinical lab units.
13 calculators · 5 converters · common conversions
Moles and Concentration
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Molar Mass Calculator
M = Σ nᵢ Aᵢ
nᵢ number of atoms of each element, Aᵢ its standard atomic weight (g/mol)
Example: Sulfuric acid, H2SO4: Molar mass M = 98.072 g/mol.
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Moles Calculator
n = m / M
n amount (mol), m mass (g), M molar mass (g/mol); particles N = n × Nₐ
Example: 36.03 g of water (M = 18.015 g/mol): Amount of substance n = 2 mol.
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- Molarity Calculator – Mass, molar mass and volume → molarity; or the mass to weigh out for a target molarity.
- Dilution Calculator – Stock and target concentrations and volume → how much stock and solvent to mix.
Acids, Bases and Gases
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pH Calculator
pH = −log₁₀[H⁺], pH + pOH = 14
[H⁺] hydrogen-ion concentration (mol/L), [OH⁻] hydroxide concentration; pKw = 14 at 25 °C
Example: A solution with [H⁺] = 0.001 mol/L (0.001 M HCl): pH = 3.
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Combined Gas Law Calculator
P₁V₁ / T₁ = P₂V₂ / T₂
P pressure, V volume, T absolute temperature (K) for a fixed amount of gas
Example: 2 L of gas at 1 atm and 20 °C heated to 100 °C while the pressure doubles to 2 atm: Final volume V₂ = 1.2729 L.
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Ideal Gas Law Calculator
P V = n R T
P absolute pressure, V volume, n amount of gas, T absolute temperature, R = 8.314462618 J/(mol·K)
Example: 1 mol at 0 °C and 101.325 kPa occupies 22.414 L.
Clinical Lab Units
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Blood Sugar Converter
mmol/L = mg/dL ÷ 18.0156
glucose C₆H₁₂O₆, molar mass 180.156 g/mol; 1 mmol/L = 18.0156 mg/dL
Example: A glucose reading of 100 mg/dL: Glucose = 5.55074 mmol/L.
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HbA1c Converter
IFCC = (NGSP − 2.15) × 10.929, eAG = 28.7 × A1c − 46.7
NGSP in %, IFCC in mmol/mol, eAG estimated average glucose in mg/dL (ADAG study)
Example: An HbA1c of 7 %: HbA1c (IFCC) = 53.0056 mmol/mol.
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- Cholesterol Converter – Cholesterol or triglycerides in mg/dL or mmol/L → the other unit.
- Lab Unit Converter – A lab test and value → the value in the other unit system, with the factor and its basis.
Nuclear Chemistry
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Half-Life Calculator
N = N₀ (½)^(t / T½)
N amount left, N₀ initial amount, t elapsed time, T½ half-life; λ = ln 2 / T½
Example: 100 g of carbon-14 (half-life 5730 years) after 11,460 years: Amount remaining N = 25.
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E = mc² Calculator
E = m c²
E energy (J), m mass (kg), c = 299,792,458 m/s exactly
Example: Converting 1 gram of mass entirely into energy: Energy E = 89875500000000 J.
Unit Converters for Chemistry
- Weight and Mass Converter – kg, g, mg, lb, oz, st, t, ton, oz t, ct
- Volume Converter – L, mL, m³, ft³, in³, US gal, imp gal
- Density Converter – kg/m³, g/cm³, g/mL, lb/ft³, lb/gal, mg/L
- Pressure Converter – Pa, kPa, psi, bar, inH₂O, mmHg, torr, atm
- Temperature Converter – °C, °F, K, °R
Common Chemistry Conversions
Using these chemistry calculators
Almost every quantitative chemistry problem passes through the mole. The molar mass calculator reads a formula, including brackets and hydrates such as CuSO4·5H2O, and adds up IUPAC standard atomic weights; the moles calculator turns grams into moles and particles; and the molarity and dilution calculators turn moles into the concentrations you prepare at the bench. Each shows its working, so the same tools double as a check on homework and lab notebooks.
Units cause most mistakes. Molarity is moles per litre of solution, not of water added; dilutions only need C₁ and C₂ in the same unit; gas-law temperatures must be absolute, which is why the gas calculators accept °C and °F but convert to kelvin before using them; and pH is a logarithm, so a factor of ten in concentration changes pH by exactly one.
The clinical lab converters switch results between the US conventional units (mg/dL, ng/mL) and the SI units used in most other countries (mmol/L, nmol/L). Each factor comes from the substance’s molar mass, and the calculator shows its basis. They convert units only: reference ranges and the meaning of a result belong with the laboratory and your clinician.