No.

Year

Method

Planck’s constant value

Relative uncertainty

Absolute uncertainty

α range

Comparative uncertainty

Ref.

m2∙kg・s−2

m²・kg・s−2

m²・kg・s−2

1

2007

NIST watt balance

6.626068912

0.36

2.38538481

2.3

0.1037

[34]

2

2007

NPL watt balance

6.626071213

2.0

13.2521424

0.5762

[35]

3

2010

CODATA

6.626069573

0.44

2.91547061

0.1268

[19]

4

2011

METAS watt balance

6.626069120

2.9

19.2156004

0.8355

[36]

5

2011

N-Avog

6.626070000

0.30

1.98782102

0.0863

[37]

6

2014

NIST watt balance

6.626069793

0.45

2.98173141

0.1296

[38]

7

2014

NRC watt balance

6.626070341

0.14

0.95415413

0.0415

[39]