Daltons to Grams (Da to g)

1 dalton equals 1.660539069×10⁻²⁴ grams (rounded).

1 dalton = 1.660539069×10⁻²⁴ grams

How to convert daltons to grams

To convert daltons to grams, multiply the number of daltons by 1.660539069×10⁻²⁴. The factor is rounded to 10 significant digits. To go the other way, multiply grams by 6.022140754×10²³ (rounded).

grams = daltons × 1.660539069×10⁻²⁴

Example: 10 daltons = 1.660539069×10⁻²³ grams.

Approximate value. Standards for the dalton varied by place and period, so this converter uses the most commonly cited value. Treat results as estimates, not exact figures.

About these units

Dalton (Da)

ScientificCurrent unitApproximate value

About 1.66054×10⁻²⁷ kg, one twelfth of the mass of a carbon-12 atom. Used for atoms, molecules and proteins.

Chemists and biologists quote the mass of a protein as so many kilodaltons, a habit that goes back to John Dalton, who in 1803 suggested taking the lightest atom, hydrogen, as the natural yardstick for atomic weights. The unit itself took other forms for a long time. Around 1903 chemists settled on one sixteenth of an oxygen atom, and in 1960 and 1961 the physics and chemistry unions replaced that with a carbon-12 standard, calling it the unified atomic mass unit with the symbol u.

The name dalton, symbol Da, was proposed by IUPAC in 1993 and endorsed by IUPAP in 2005. It is the same unit as u and is defined as one twelfth of the mass of a free carbon-12 atom at rest in its ground state. The 2022 CODATA value, listed by NIST and in Wikipedia, is 1.66053906892 x 10^-27 kg, with a small uncertainty in the final digits. A helium-4 atom weighs about 4.0026 Da, and the giant protein titin about 3 to 3.7 MDa. The BIPM accepts the unit for use with the SI, and the 2019 redefinition of the kilogram left its definition unchanged.

1 dalton = 1.660539069×10⁻²⁷ kilograms (approximately).

Sources: Wikipedia: Dalton (unit); NIST CODATA: unified atomic mass unit

Gram (g)

Metric (SI)Current unit

One thousandth of a kilogram. The standard unit for food quantities and small objects.

A gram was once defined as a small drop of the natural world. The French National Convention of 1795 set it as the absolute weight of a volume of pure water equal to a cube one hundredth of a metre on each side, a cubic centimetre. The reference temperature was first the melting point of ice and was later changed to the temperature of maximum density of water, about 4 degrees Celsius. The word came into French as gramme, from Late Latin gramma, itself from the Greek for a letter or small mark; in Late Antiquity it meant about one twenty-fourth of an ounce.

The gram was the base unit of mass in the centimetre-gram-second system, but in 1960 the SI took the kilogram as its base unit, which made the gram one thousandth of it. That is why it appears in so many everyday places: it is the standard for non-liquid ingredients in cooking and shopping, and nutrition labels commonly list contents per 100 g. For a sense of scale, a small paper clip or a pen cap weighs about a gram, and a Japanese 1-yen coin is close to exactly that, while a US penny is around 2.5 g.

1 gram = 0.001 kilograms (exactly).

Sources: Wikipedia: Gram; Wikipedia: Kilogram

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