Dalton Converter

A dalton converter translates between the dalton (Da), also known as the atomic mass unit (amu), and other units of mass used in chemistry, biochemistry, and molecular biology. The dalton is the standard unit for expressing the mass of atoms, molecules, proteins, and other microscopic entities. Named after John Dalton, the English chemist who formulated modern atomic theory, one dalton is defined as exactly one-twelfth of the mass of a single carbon-12 atom.

At the atomic scale, masses are incredibly small by everyday standards. A single hydrogen atom weighs approximately 1.008 daltons, a water molecule weighs about 18.015 daltons, and a typical protein might weigh between 10,000 and 100,000 daltons (often expressed as kilodaltons, kDa). A single DNA base pair weighs roughly 650 daltons. These microscopic masses require specialized units that avoid unwieldy numbers of zeros, which is why the dalton and its multiples are preferred in the life sciences.

This converter transforms daltons into grams, kilograms, yoctograms, electron masses, and kilodaltons. The gram and kilogram conversions are essential for bridging the molecular scale with laboratory-scale measurements. The electron mass conversion provides a useful reference for comparing atomic and subatomic masses. The yoctogram conversion (1 Da = 1.66054 yg) is particularly convenient because it provides a numerically simple representation of atomic-scale masses.

The dalton has a precisely defined relationship to the gram, derived from the definition of the atomic mass unit in terms of the carbon-12 atom and Avogadro's number.

Understanding the dalton in context requires familiarity with the mass ranges encountered across chemistry and biology.

• Atomic masses: Individual atoms range from about 1 Da (hydrogen) to over 200 Da (uranium). Carbon-12 is exactly 12 Da by definition. The periodic table lists average atomic masses accounting for natural isotopic abundances.
• Small molecules: Water (H₂O) weighs 18.015 Da, glucose (C₆H₁₂O₆) weighs 180.16 Da, and caffeine (C₈H₁₀N₄O₂) weighs 194.19 Da. These molecular weights are fundamental to stoichiometry and solution preparation.
• Proteins: Range from about 5,000 Da (small peptides) to over 500,000 Da (large multi-subunit complexes). Insulin weighs 5,808 Da, hemoglobin weighs 64,500 Da, and titin, the largest known protein, weighs approximately 3,816,000 Da (3,816 kDa).
• Nucleic acids: A single DNA base pair weighs approximately 650 Da. A complete human chromosome containing 100 million base pairs weighs about 65 billion daltons (65 MDa).
• Viral particles: A typical virus particle weighs between 10 million and 1 billion daltons. The tobacco mosaic virus weighs about 40 MDa, while a bacteriophage can weigh over 200 MDa.