Handbook 44 – 2022 2.23. Weights

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Table of Contents

Page

Section 2.23. Weights........................................................................................................... 2-93

A. Application .................................................................................................................................................. 2-93

A.1. General................................................................................................................................................2-93

A.2. Exceptions...........................................................................................................................................2-93

A.3. Additional Code Requirements...........................................................................................................2-93

S. Specifications............................................................................................................................................... 2-93

S.1. Material...............................................................................................................................................2-93

S.2. Design.................................................................................................................................................2-93

S.2.1. Surface......................................................................................................................................2-93

S.2.2. Ring..........................................................................................................................................2-93

S.3. Adjusting Material. .............................................................................................................................2-93

S.4. Marking Requirements........................................................................................................................2-93

S.4.1. General. ....................................................................................................................................2-93

S.4.2. Apothecaries’ Weights. ............................................................................................................2-93

S.4.3. Troy Weights............................................................................................................................2-93

S.4.4. Metric Weights.........................................................................................................................2-93

S.4.5. Carat Weights...........................................................................................................................2-93

S.4.6. Counterpoise Weight................................................................................................................2-93

N. Notes............................................................................................................................................................. 2-94

N.1. Testing Procedures..............................................................................................................................2-94

T. Tolerances.................................................................................................................................................... 2-94

T.1. In Excess and in Deficiency................................................................................................................2-94

T.2. On Avoirdupois Weights. ...................................................................................................................2-94

T.3. On Metric Weights..............................................................................................................................2-96

T.4. On Carat Weights................................................................................................................................2-96

T.5. On Apothecaries and Troy Weights....................................................................................................2-97
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This publication is available free of charge from: https://doi.org/10.6028/NIST.HB.44-2022

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Handbook 44 – 2022 2.23. Weights

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This publication is available free of charge from: https://doi.org/10.6028/NIST.HB.44-2022

Section 2.23. Weights

A. Application

A.1. General. – This code applies to commercial weights; that is, weights used in connection with commercial 

weighing devices.

A.2. Exceptions. – This code does not apply to test weights or to other “standards” of mass.

A.3. Additional Code Requirements. – In addition to the requirements of this code, Weights shall meet the 

requirements of Section 1.10. General Code.

S. Specifications

S.1. Material. – The material used for weights shall be as follows:

(a) Weights of 6 g or 100 gr and larger shall be made of a metal, or a metal alloy, not softer than brass.

(b) Weights of less than 6 g or 100 gr may be made of aluminum, but shall not be made of iron or of unplated 

steel, except stainless steel.

S.2. Design.

S.2.1. Surface. – The surface of a weight shall be smooth and shall not be coated with thick, soft, or brittle 

material. A weight of more than 2 g or 30 gr or shall not have sharp edges, points, or corners.

S.2.2. Ring. – A ring on a weight shall not be split or removable.

S.3. Adjusting Material. – Adjusting material shall be securely positioned and shall not project beyond the surface 

of the weight.

S.4. Marking Requirements.

S.4.1. General. – A weight shall be marked to show clearly its nominal value, which shall include identification 

of the unit; however, the nominal value of a weight of 30 gr or 2 g, or less, may be designated by dots, lines, 

figures, distinctive shape, or other appropriate means.

S.4.2. Apothecaries’ Weights. – On apothecaries’ dram, ounce, and pound weights, the letters “ap” shall be 

used in combination with the nominal value and the appropriate abbreviation of or symbol for the unit.

S.4.3. Troy Weights. – On troy ounce and pound weights, the letter “t” shall be used in combination with the 

nominal value and the appropriate symbol of the unit.

S.4.4. Metric Weights. – On metric weights, the symbols “kg,” “g,” and “mg” shall be used in combination 

with the nominal value of kilograms, grams, and milligrams, respectively.

S.4.5. Carat Weights. – On carat weights, the letter “c” shall be used in combination with the nominal value.

S.4.6. Counterpoise Weight. – A counterpoise weight shall be marked to show clearly both its nominal value 

and the value it represents when used on the multiplying-lever scale for which it is intended.
2.23. Weights Handbook 44 – 2022

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This publication is available free of charge from: https://doi.org/10.6028/NIST.HB.44-2022

N. Notes

N.1. Testing Procedures. – Commercial weights should be tested on a precision balance using standard weights, 

the errors of which, when used without correction, do not exceed 1

/3 of the smallest tolerance to be applied. (Also see 

Appendix A, Fundamental Considerations, paragraphs 3.2. Tolerance for Standards and 3.3. Accuracy of Standards.)

T. Tolerances

T.1. In Excess and In Deficiency. – The tolerances hereinafter prescribed shall be applied equally to errors in 

excess and errors in deficiency.

T.2. On Avoirdupois Weights. – The maintenance tolerances shall be as shown in Table 1. Maintenance Tolerance 

for Avoirdupois Weights. Acceptance tolerances shall be one-half the maintenance tolerances.
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Table 1.

Maintenance Tolerance for Avoirdupois Weights

Maintenance Tolerance

Nominal 

Value

Equal-Arm

Weights

Counterpoise Weights

For scales with multiples of 

less than 1000

For scales with multiples of 

1000 or over

oz grains mg grains mg grains mg

1

/64 0.1 6

1

/32 0.3 19

1

/16 0.4 26

1

/8 0.5 32

1⁄4 1.0 65

1⁄2 1.5 97 1.0 65

1 1.7 110 1.0 65

2 2.0 130 1.0 65

3 2.0 130 1.5 97

4 3.0 190 1.5 97 1.0 65

5 3.5 230 1.5 97 1.0 65

6 3.5 230 1.5 97

8 4.0 260 2.0 130 1.5 97

10 4.0 260 2.5 160 2.0 130

12 5.0 320 2.5 160 2.0 130

lb Grains mg grains mg grains mg

1 5.0 320 3.0 190 2.5 160

2 7.0 450 6.0 390 4.0 260

3 9.0 580 9.0 580 5.0 320

4 11.0 710 11.0 710 6.0 390

5 15.0 970 12.0 780 6.5 420

6 17.0 1190

7 19.0 1200

8 21.0 1400 15.0 970 9.0 580

9 23.0 1500

10 25.0 1600 18.0 1160 10.0 650

15 28.0 1800

20 30.0 1900

25 35.0 2300

30 40.0 2600

40 45.0 2900

50 50.0 3200
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T.3. On Metric Weights. – The maintenance tolerances shall be as shown in Table 2. Maintenance Tolerances for 

Metric Weights. Acceptance tolerances shall be one-half the maintenance tolerances.

T.4. On Carat Weights. – The maintenance tolerances shall be as shown in Table 2. Maintenance Tolerances for 

Metric Weights. Acceptance tolerances shall be one-half the maintenance tolerances.

Table 2.

Maintenance Tolerances for Metric Weights

Nominal

Value

(mg)

Maintenance

Tolerance

(mg)

Nominal

Value

(g)

Maintenance

Tolerance

(mg)

5 or less

10

20

30

50

100

200

300

500

0.1

0.3

0.4

0.6

0.8

1.0

1.5

2.0

3.0

1

2

3

5

10

20

30

50

100

200

300

500

4

6

8

10

15

20

30

40

70

100

150

175

Nominal

Value

(kg)

Maintenance

Tolerance

(mg)

Nominal

Value

(carats)

Maintenance

Tolerance

(mg)

1

2

3

5

10

20

250

400

500

800

 1000

1500

0.25*

0.5**

1.0

2.0

3.0

5.0

10.0

20.0

30.0

50.0

100.0

0.6

1.0

1.5

2.0

3.0

4.0

6.0

10.0

12.0

15.0

25.0

*25 points or less

**50 points
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T.5. On Apothecaries and Troy Weights. – The maintenance tolerances shall be as shown in Table 3. Maintenance 

Tolerances for Apothecaries’ and Troy Weights. Acceptance tolerances shall be one-half the maintenance tolerances.

Table 3.

Maintenance Tolerances for Apothecaries’ and Troy Weights

Nominal

Value Maintenance Tolerance NominalValue Maintenance Tolerance

grains grains mg oz grains mg

1

2

3

5

10

20

0.01

0.02

0.03

0.03

0.04

0.06

0.6

1.3

2.0

2.0

2.5

4.0

1

2

3

4

5

0.4

0.6

1.0

1.5

1.6

25.0

40.0

65.0

100.0

105.0

scruples grains mg oz grains mg

1

2

0.06

0.10

4.0

6.5

6

7

8

9

10

1.8

1.9

2.0

2.1

2.2

115.0

125.0

130.0

135.0

145.0

dr grains mg oz grains mg

0.5

1.0

2.0

3.0

4.0

5.0

6.0

0.07

0.10

0.20

0.30

0.40

0.50

0.60

4.5

6.5

13.0

20.0

25.0

30.0

40.0

11

12

20

30

50

2.4

2.5

2.9

3.7

5.4

155.0

160.0

190.0

240.0

350.0

dwt grains mg oz grains mg

1

2

3

4

5

10

0.06

0.10

0.15

0.20

0.30

0.40

4.0

6.5

10.0

13.0

20.0

25.0

100

200

300

500

1 000

7.7

12.3

15.4

23.1

38.6

500.0

800.0

1 000.0

1 500.0

2 500.0
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