Determination of the Planck constant at the national institute of Standards and Technology

In 2013, a new measurement of the Planck constant h was performed using a watt balance at the National Institute of Standards and Technology (NIST). The value is h = 6.626 069 79(30) × 10
^-34
Js. The relative standard uncertainty of this determination is 45 × 10
^-9
.