u to Grams Converter

The atomic mass unit (u) — also called a dalton — is the tiny unit used to express the mass of atoms and molecules, and converting it to grams requires a precise scientific constant. Enter your Value to Convert and select your Conversion Direction (u → g or g → u) to get the Converted Value in your target unit. Secondary outputs include the Conversion Factor Used and the result expressed in Scientific Notation. Also try the Grams to Moles Calculator.

Conversion Direction *

Number of decimal places in the result

Results

Converted Value

--

Conversion Factor Used

--

Scientific Notation

--

Results Table

Frequently Asked Questions

What is an atomic mass unit (u)?

An atomic mass unit (u) is defined as one-twelfth of the mass of a carbon-12 atom. It's approximately 1.66054 × 10⁻²⁴ grams and is commonly used to express atomic and molecular masses. See also our Actual Yield Calculator.

How do you convert atomic mass units to grams?

To convert u to grams, multiply the atomic mass unit value by 1.66053906660 × 10⁻²⁴. This conversion factor is based on the exact definition of the atomic mass unit.

What is Avogadro's number and how is it used in this conversion?

Avogadro's number is 6.02214076 × 10²³ mol⁻¹. It's used to convert between atomic scale masses (u) and macroscopic masses (grams) by relating the mass per particle to the mass per mole.

Why is 1 u approximately equal to 1 g/mol?

This is by definition. The atomic mass unit was defined so that the mass of one mole of atoms (in grams) equals the atomic mass in u. This makes calculations between atomic and molar scales convenient. You might also find our Moles to Atoms Converter useful.

Can I convert grams back to atomic mass units?

Yes, to convert grams to atomic mass units, divide the gram value by 1.66053906660 × 10⁻²⁴, or multiply by 6.02214076 × 10²³.

What's the difference between u and amu?

Both u and amu (atomic mass unit) refer to the same unit. The symbol 'u' is the modern SI symbol, while 'amu' is the older notation still commonly used.

How accurate is this conversion?

The conversion uses the exact CODATA value for the atomic mass unit constant: 1.66053906660 × 10⁻²⁴ kg, providing scientific-grade accuracy for all calculations.