Instant · Precise · Universal
34 units available
6 categories total
To convert Da to kg: multiply by 1.6605390666 × 10⁻²⁷. 1 kDa = 1,000 Da.
1 Da = 1 u = 1.6605390666 × 10⁻²⁷ kg. Proteins range from ~5 kDa to >1,000 kDa.
For example, 1 Dalton (Da) = 1.660539e-9 Femtogram (fg).
| Dalton (Da) | Femtogram (fg) |
|---|---|
| 0.1 | 1.660539e-10 |
| 0.5 | 8.302695e-10 |
| 1 | 1.660539e-9 |
| 2 | 3.321078e-9 |
| 5 | 8.302695e-9 |
| 10 | 1.660539e-8 |
| 25 | 4.151348e-8 |
| 50 | 8.302695e-8 |
| 100 | 1.660539e-7 |
| 500 | 8.302695e-7 |
| 1000 | 0.000001660539067 |
The dalton is a unit of mass equal to one unified atomic mass unit (1/12 of a carbon-12 atom), approximately 1.661 × 10⁻²⁷ kg.
1 Da = 1 u = 1.6605390666 × 10⁻²⁷ kg. Proteins range from ~5 kDa to >1,000 kDa.
To convert Da to kg: multiply by 1.6605390666 × 10⁻²⁷. 1 kDa = 1,000 Da.
Protein molecular weights (hemoglobin ≈ 64.5 kDa), DNA fragment sizing, and antibody characterization.
Titin, the largest known protein, has a molecular weight of about 3,800 kDa (3.8 MDa). The average protein is ~40–50 kDa.
The dalton and u are identical — they're just preferred in different fields (Da in biology, u in chemistry/physics).
If a paper says a protein is '50 kDa,' that's 50,000 atomic mass units — about 50,000 hydrogen atoms' worth of mass.
The femtogram is a unit of mass equal to 10⁻¹⁵ grams or 10⁻¹⁸ kilograms — one quadrillionth of a gram.
1 fg = 10⁻¹⁵ g = 10⁻¹⁸ kg = 1,000 ag.
To convert fg to kg: multiply by 10⁻¹⁸. To convert fg to pg: divide by 1,000.
Expressing the mass of individual bacterial cells (~100 fg for E. coli) and subcellular components.
A single E. coli bacterium has a mass of about 600–700 fg. A single mitochondrion is roughly 1 fg.
Mixing up fg (femtogram) with fm (femtometer) — one is mass, the other is length.
A bacterium weighs ~500 fg — this gives you a tangible anchor for the femtogram scale.



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