Instant · Precise · Universal
34 units available
6 categories total
To convert u to kg: multiply by 1.6605390666 × 10⁻²⁷. To convert u to MeV/c²: multiply by 931.494.
1 u = 1.6605390666 × 10⁻²⁷ kg = 1/Nₐ grams ≈ 931.494 MeV/c².
For example, 1 Atomic Mass Unit (u) = 1.693279e-28 Kilogram-force second²/meter (kgf·s²/m).
| Atomic Mass Unit (u) | Kilogram-force second²/meter (kgf·s²/m) |
|---|---|
| 0.1 | 1.693279e-29 |
| 0.5 | 8.466393e-29 |
| 1 | 1.693279e-28 |
| 2 | 3.386557e-28 |
| 5 | 8.466393e-28 |
| 10 | 1.693279e-27 |
| 25 | 4.233197e-27 |
| 50 | 8.466393e-27 |
| 100 | 1.693279e-26 |
| 500 | 8.466393e-26 |
| 1000 | 1.693279e-25 |
The atomic mass unit (unified) is defined as 1/12 the mass of a carbon-12 atom, approximately 1.661 × 10⁻²⁷ kilograms.
1 u = 1.6605390666 × 10⁻²⁷ kg = 1/Nₐ grams ≈ 931.494 MeV/c².
To convert u to kg: multiply by 1.6605390666 × 10⁻²⁷. To convert u to MeV/c²: multiply by 931.494.
Molecular weight calculations, mass spectrometry data interpretation, and chemical stoichiometry.
A proton has a mass of ~1.007 u, a neutron ~1.009 u. The discrepancy from 1.000 reflects nuclear binding energy.
Confusing 'amu' (the old, obsolete term) with 'u' (the unified standard). Also, forgetting that 1 u ≠ 1 gram.
Think of u as 'approximately the mass of one proton or neutron.' Carbon-12 = 12 u exactly (by definition).
The kilogram-force second squared per meter is an engineering unit of mass in the gravitational metric system, equal to about 9.807 kg.
1 kgf·s²/m = 9.80665 kg (exactly), based on standard gravity g₀ = 9.80665 m/s².
To convert to kilograms: multiply by 9.80665.
Historical engineering calculations where force was in kgf and F=ma needed consistent units.
This unit is the metric equivalent of the slug (imperial system). Just as 1 lb-force accelerates 1 slug at 1 ft/s², 1 kgf accelerates this unit at 1 m/s².
Mixing up mass (kg) and weight (kgf) in the gravitational system. SI removed this confusion by using newtons for force.
This unit exists because the gravitational system used kgf (force) as base, so a derived mass unit was needed for F=ma to work.



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