Metric Conversion tips

Guidelines for determining various units of measure

Approximate Measurement Conversion Chart
also try: WORLD WIDE METRIC for more options!

Millimeters to Inches Conversion Chart

1 inch = 25.4mm
Size in mm	Closest equivalent in Inches
1mm	just over 1/32 of an inch
2mm	just over 1/16 of an inch
3mm	1/8 of an inch
4mm	5/32 of an inch
5mm	3/16 of an inch
6mm	1/4 of an inch
7mm	9/32 of an inch
8mm	5/16 of an inch
9mm	11/32 of an inch
10mm	3/8 of an inch
11mm	7/16 of an inch
12mm	15/32 of an inch
13mm	1/2 of an inch
14mm	9/16 of an inch
15mm	19/32 of an inch
16mm	10/16 of an inch
17mm	11/16 of an inch
18mm	23/32 of an inch
19mm	3/4 of an inch
20mm	13/16 of an inch
25mm	15/16 of an inch
34mm	1.34 inch

1mm = 1/32"

8mm = 5/16"

2mm = 1/16"

9mm = almost 3/8"

3mm = 1/8"

10mm = 5/16"

4mm = 5/32"

11mm = 7/16"

5mm = 3/16"

12mm = almost 1/2"

6mm = almost 1/4"

20mm = almost 13/16"

7mm = almost 1/4"

25mm = almost 1"

Inches to MM: (in * 25.4)

1/8" = 4mm

1/2" = 12.5mm

1/4" = 6.5mm

1" = 25.4mm

Grams to Pounds: (g * 0.002205)

1g = 0.0022 lb

5g = 0.01 lb

100g = 0.22 lb

453.6g = 1 lb

500g = 1.10 lbs

1 Kg = 2.2046 lbs

Ounces to Pounds

1oz = 0.625 lb

8 oz = 1/2 lb

16 oz= 1 lb

Other Measurements

1 Troy oz = 31g

1 Avoirdupois oz = 28g

Wire Gauge

Wire gauge is best remembered in wire thickness or gauge: The larger the number, the smaller the diameter of the wire.

Gauge

Inches

Millimeters

10

0.102

2.59

11

0.091

2.31

12

0.081

2.06

13

0.072

1.83

14

0.064

1.63

15

0.057

1.45

16

0.052

1.32

17

0.045

1.14

18

0.04

1.02

19

0.036

0.91

20

0.032

0.81

21

0.028

0.71

22

0.025

0.64

23

0.023

0.58

24

0.02

0.51

25

0.0179

0.455

26

0.0159

0.404

27

0.0142

0.361

28

0.0126

0.32

29

0.0113

0.287

30

0.01

0.25

31

0.0089

0.226

32

0.008

0.2

33

0.0071

0.18

34

0.0063

0.16

35

0.0056

0.142

36

0.005

0.13

37

0.0045

0.114

38

0.004

0.1

This chart shows you the approximate number of beads for various lengths.

(length of strand excludes clasp)

Beads Per Inch Chart
Bead Size (mm)	1"	4"	16"	20"	24"	28"	32"
3	8.46	33.8	136	170	204	237	271
4	6.35	25.4	102	127	153	178	204
5	5.08	20.32	82	102	125	143	164
6	4.23	16.9	68	84	101	118	136
7	3.62	14.4	58	70	86	101	116
8	3.17	12.68	51	64	76	89	102
10	2.54	10.16	41	51	61	71	81
12	2.11	8.44	34	42	51	59	68
14	1.81	7.24	29	36	43	50	58
16	1.58	6.32	25	32	38	44	51
18	1.41	5.64	23	28	34	39	45

How big are the bead holes?

Czech Round Beads
Bead	Hole Size (mm)	Hole Size (inches)	Max. Size Metal Wire to Use
4mm	1.03	0.04	18GA
6mm	1.05	0.04	18GA
8mm	1.05	0.045	18GA
10mm	1.31	0.051	18GA
Hemalyke
Bead	Hole Size (mm)	Hole Size (inches)	Max. Size Metal Wire to Use
2mm	0.92	0.036	20GA
3mm	0.92	0.036	20GA
4mm	0.92	0.036	20GA
6mm	0.92	0.036	20GA
8mm	0.92	0.036	20GA
10mm	1.03	0.04	18GA
12mm	1.31	0.051	16GA
shapes	0.92	0.036	20GA
Fire Polish
Bead	Hole Size (mm)	Hole Size (inches)	Max. Size Metal Wire to Use
3mm	0.92	0.036	20GA
4mm	0.92	0.036	20GA
6mm	0.92	0.036	20GA
8mm	0.92	0.036	20GA
10mm	1.03	0.04	18GA
12mm	1.7	0.067	14GA
Seed Beads
Bead	Hole Size (mm)	Hole Size (inches)	Max. Size Metal Wire to Use
Delica 11/0	0.64	0.025	22GA
Hex-2 Cut 11/0	0.65	0.025	22GA
Dyna-Mite 11/0	0.64	0.025	22GA
Ornela Czech 11/0	1.0	0.039	18GA
Rocaille 15/0	0.5	0.02	24GA
8/0	1.2	0.047	18GA
6/0	1.7	0.067	14GA
Bugle	0.82	0.032	21GA
Fringe	0.82	0.032	21GA
Square	1.5	0.059	16GA
Triangle	1.6	0.062	16GA
Bone Beads
Bead	Hole Size (mm)	Hole Size (inches)	Max. Size Metal Wire to Use
3mm	1.03	0.04	18GA
6mm	1.31	0.051	16GA
8mm	1.31	0.051	16GA
10mm	1.31	0.051	16GA
components	1.03	0.04	18GA
Pearls
Bead	Hole Size (mm)	Hole Size (inches)	Max. Size Metal Wire to Use
Natural	0.50-0.75	0.020-0.30	22GA-24GA
Glass	1.0	0.039	18GA
Swarovski® Crystal Pearls	0.9	0.035	20GA
Cane Glass
Bead	Hole Size (mm)	Hole Size (inches)	Max. Size Metal Wire to Use
All Cane Glass	0.75-3.4	0.030-0.134	14GA-22GA
Miracle Beads
Bead	Hole Size (mm)	Hole Size (inches)	Max. Size Metal Wire to Use
4mm	1.31	0.051	16GA
6mm	1.64	0.064	16GA
8mm	1.64	0.064	14GA
Wonder Beads
Bead	Hole Size (mm)	Hole Size (inches)	Max. Size Metal Wire to Use
4mm	1.0	0.039	18GA
6mm	1.0	0.039	18GA
8mm	1.0	0.039	18GA
4x4mm	1.0	0.039	18GA
5x5mm	1.0	0.039	18GA
4x7mm	1.0	0.039	18GA
Crystals (Austrian and Celestial)
Bead	Hole Size (mm)	Hole Size (inches)	Max. Size Metal Wire to Use
3mm	0.90	0.035	22GA
4mm	0.60	0.022	22GA
6mm	0.80	0.030	21GA
8mm	1.00	0.038	20GA
10mm	1.40	0.055	18GA
Gemstone Beads
Bead	Hole Size (mm)	Hole Size (inches)	Max. Size Metal Wire to Use
4mm	0.5	0.020	24GA
6mm	0.6	0.022	22GA
8mm	0.8	0.030	21GA
10mm	1.5	0.059	16GA
12mm	2.0	0.079	14GA
14mm	1.25	0.049	18GA
Chips	0.6-1.0	0.024-0.039	18GA-22GA
Nuggets	0.75-1.9	0.030-0.075	14GA-20GA

Metric Ruler for determining inches versus millimeters
(ruler shown actual size)

This is great for determining jump ring and split ring size, also bead sizes, simply by looking at the top and comparing to the bottom row.

Examples:
6mm bead------------------1/4"
12mm jump ring-----------1/2"

*Note: Bead hole sizes listed are approximate and may vary.

Number of Beads per 16 inch strand

**Please note that the number of beads listed below is an estimate only. Number of beads may vary.

Size	Number of Beads
Rounds
2mm	203
3mm	136
4mm	100
6mm	67
8mm	50
10mm	41
12mm	34