| % (w/v) ↔ molarity | c (mol/L) = (% × 10) / MW | ±0.5% rel. when density ≈ 1.0 g/mL | IUPAC (2019) |
| millimolar ↔ molar | c (mol/L) = mM × 10⁻³ | Exact | Cohen ER, Cvitaš T, Frey JG, Holmström B, Kuchitsu K, Marquardt R, Mills I, Pavese F, Quack M, Stohner J, Strauss HL, Takami M, Thor AJ (2007) |
| molarity (mol/L) | c = n/V = (m/MW)/V | ±0.1% (depends on MW precision) | IUPAC (2019) |
| parts per million (mg/L) ↔ molarity | c (mol/L) = ppm / (1000 × MW); equivalently ppm = mg/L for dilute aqueous | ±1% (density-independent for dilute solutions) | IUPAC (2019) |
| mg/mL ↔ molarity | c (mol/L) = (mg/mL × 1000) / MW / 1000 = mg/mL / MW × 1 | ±0.2% | Cohen ER, Cvitaš T, Frey JG, Holmström B, Kuchitsu K, Marquardt R, Mills I, Pavese F, Quack M, Stohner J, Strauss HL, Takami M, Thor AJ (2007) |
| g/L ↔ molarity | c (mol/L) = (g/L) / MW | ±0.1% (depends on MW precision) | Cohen ER, Cvitaš T, Frey JG, Holmström B, Kuchitsu K, Marquardt R, Mills I, Pavese F, Quack M, Stohner J, Strauss HL, Takami M, Thor AJ (2007) |
| mmol/L ↔ molarity | c (mol/L) = mmol/L × 10⁻³ | Exact | Cohen ER, Cvitaš T, Frey JG, Holmström B, Kuchitsu K, Marquardt R, Mills I, Pavese F, Quack M, Stohner J, Strauss HL, Takami M, Thor AJ (2007) |
| Celsius ↔ Kelvin | T(K) = t(°C) + 273.15 | ±0.01 K (ITS-90 scale) | BIPM (Bureau International des Poids et Mesures) (2019) |
| Celsius ↔ Fahrenheit | T(°F) = T(°C) × 9/5 + 32 | ±0.1 °F | Thompson A, Taylor BN (2008) |
| density-corrected % ↔ molarity | c (mol/L) = (%w/w × ρ × 10) / MW, ρ in g/mL | ±0.1% when ρ known to 3 decimals | Cohen ER, Cvitaš T, Frey JG, Holmström B, Kuchitsu K, Marquardt R, Mills I, Pavese F, Quack M, Stohner J, Strauss HL, Takami M, Thor AJ (2007) |
