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g/mol to Kilodaltons Converter
↔ Convert kDa to g/mol instead

Common Conversions

g/mol kDa
100 0.1
500 0.5
1000 1
5000 5
10000 10
25000 25
50000 50
100000 100
150000 150
500000 500
1000000 1000
5000000 5000

Why this conversion matters in chemistry

An expressed-protein construct gets a molar mass from a sequence-derived calculation in g/mol; the SDS-PAGE gel running next door has its ladder labelled in kDa. A 66,430 g/mol BSA-sized construct lands at 66.4 kDa, right between the 50 and 75 kDa standard bands. The ratio of 1000 falls cleanly out of 1 kDa = 1000 Da and the 1 Da = 1 g/mol identity. The conversion is a routine unit conversion that takes a calculated molecular weight from sequence-based protein analysis into the kDa form gel filtration columns, MWCO membranes, and Western-blot ladders are calibrated against.

Formula

kDa = g/mol ÷ 1000

Worked Examples

66430 g/mol = 66.43 kDa

Bovine serum albumin — the calibration anchor for many protein-quantitation curves.

150000 g/mol = 150 kDa

An IgG antibody — the reference molecular weight for any antibody-based assay.

1000 g/mol = 1 kDa

The factor anchor — about a 9-residue peptide expressed at the kDa scale.

25000 g/mol = 25 kDa

A small protein — about the size of an antibody light chain or chymotrypsin.

Frequently Asked Questions

How do I convert g/mol to kDa?
Divide by 1000. So 150,000 g/mol becomes 150 kDa — an IgG antibody. The factor is exact through the kilo prefix and the 1 Da = 1 g/mol identity.
When does kDa get used?
Biochemistry, proteomics, and molecular biology default to kDa for any protein-scale molecule. SDS-PAGE ladders, gel-filtration calibration, and ultrafiltration membrane cutoffs all label in kDa rather than the bigger g/mol numbers.
What's a megadalton?
1 MDa = 1000 kDa = 10⁶ g/mol. The MDa scale describes ribosomes, viral capsids, and supramolecular complexes — assemblies too large for the kDa scale to read cleanly.