Daltons to Kilodaltons Converter
Common Conversions
| Da | kDa |
|---|---|
| 100 | 0.1 |
| 500 | 0.5 |
| 1000 | 1 |
| 5000 | 5 |
| 10000 | 10 |
| 25000 | 25 |
| 50000 | 50 |
| 66500 | 66.5 |
| 100000 | 100 |
| 150000 | 150 |
| 500000 | 500 |
| 1000000 | 1000 |
Why this conversion matters in chemistry
Peptides come off a mass spectrometer in daltons — a tryptic fragment around 1500 Da, an intact small protein around 14,000. SDS-PAGE bands and size-exclusion chromatography apparent molecular weights live in kilodaltons — lysozyme at 14.3 kDa, BSA at 66.5, an IgG at 150. The conversion is dividing by 1000, but it earns its keep when a precision MS measurement of a peptide has to land in the same conversation as a gel-band annotation done at three significant figures. Same number, different scale, depending on which technique generated it.
Formula
Worked Examples
Bovine serum albumin (BSA) — the standard protein-chemistry molecular-weight reference.
Roughly the mass of a small peptide — about nine residues, depending on composition.
An intact IgG antibody — the size that gives a single band on a non-reducing SDS-PAGE gel.
About the size of a small monomeric enzyme like chymotrypsin or trypsin (~23–25 kDa) — the kind that gives a clean single band at the lower end of an SDS-PAGE gel.