Lab Unit Converter
Convert between molarity and mass concentration in either direction. Molecular weight is required because molar concentration counts molecules while mass concentration measures their mass.
Calculations run locally in your browser. Values are only placed in a URL when you choose “Copy Shareable Link.”
µg/mL = nM × molecular weight (g/mol) ÷ 1,000,000
Multiplying nM by 10−9 mol/L and g/mol gives g/L. Converting g/L to µg/mL supplies the remaining factor of 1,000, producing the division by 1,000,000 shown above.
Example: 100 nM of a 50 kDa protein is 5 µg/mL. Use the molecular weight of the exact molecular form.
ng/mL = µM × molecular weight (g/mol)
µM contributes 10−6 mol/L. After multiplication by g/mol, converting g/L to ng/mL contributes 106, so the numerical scale factors cancel.
Example: 2 µM of a 500 g/mol compound is 1,000 ng/mL. Use the molecular weight of the exact molecular form.
nM = µg/mL × 1,000,000 ÷ molecular weight (g/mol)
Convert µg/mL to g/L, divide by g/mol to obtain mol/L, then scale mol/L to nM. The mass units cancel against molecular weight.
Example: 5 µg/mL of a 50 kDa protein is 100 nM. Use the molecular weight of the exact molecular form.
µM = ng/mL ÷ molecular weight (g/mol)
ng/mL converts to 10−6 g/L. Dividing by g/mol gives mol/L, and multiplying by 106 converts that result to µM, canceling the scale factors.
Example: 1,000 ng/mL of a 500 g/mol compound is 2 µM. Use the molecular weight of the exact molecular form.
µM = mg/mL × 1,000,000 ÷ molecular weight (g/mol)
One mg/mL is one g/L. Dividing g/L by g/mol produces mol/L, then multiplying by 1,000,000 produces µM.
Example: 1 mg/mL of a 50 kDa protein is 20 µM. Use the molecular weight of the exact molecular form.
mg/mL = molarity (M) × molecular weight (g/mol)
M is mol/L. Multiplication by g/mol cancels moles and gives g/L, which is numerically equivalent to mg/mL.
Example: 1 M NaCl at 58.44 g/mol is 58.44 mg/mL. Use the molecular weight of the exact salt and hydration state.
Use the molecular weight of the exact material being measured: salt or free form, hydrate or anhydrous form, conjugate or labeled form, monomer or oligomer, and full protein construct or processed chain. A nominal protein value in kDa may be rounded and is not automatically an exact molecular weight. The converter does not infer molecular identity, density, purity, or formulation.
Save conversions and timed protocols with RayCrest Lab Calculator. Continue into plasmid, primer, cloning, sequencing, and protein workflows with RayCrest MDS for Mac.
