One septillionth of a gram (10^-24 g). This is the mass scale of single subatomic particles. A single proton or neutron has a mass of approximately 1.67 yoctograms. It is used in particle physics and advanced mass spectrometry.
Heard on the job
The nanomechanical resonator is sensitive enough to detect mass changes of a single yoctogram.
Insider tip
When calculating atomic mass, one atomic mass unit (Dalton) is roughly 1.66 yoctograms.