Metric Bolts, Nuts & Washers

This table presents the most commonly used varieties of small to medium size metric hardware. Nut dimensions are maximums per ISO. Washer dimensions are for the regular size (vs. narrow or wide). All dimensions are in inches. Be aware that a search for hardware dimensions will yield variable results since many reported dimensions are manufacturers' production values, not necessarily the official ISO values.

Note: For critical applications, consult official ISO manuals to obtain dimensions.

Click here for a table of SAE hardware sizes.

All sizes are millimeters (mm).

Screw Size			Tap Drill Size	Clearance Drill Size	Nut Points	Nut Flats	Washer I.D.	Washer O.D.
Diameter	Pitch	Series
1	0.20	Fine	0.80	1.20	2.08	1.80	1.0	2.0
	0.25	Coarse	0.75
1.1	0.20	Fine	0.90	1.30
	0.25	Coarse	0.85
1.2	0.20	Fine	1.00	1.50
	0.25	Coarse	0.95
1.4	0.20	Fine	1.20	1.70
	0.30	Coarse	1.10
1.6	0.20	Fine	1.40	2.00	3.70	3.2	1.7	4.0
	0.35	Coarse	1.25
1.8	0.20	Fine	1.60	2.20
	0.35	Coarse	1.45
2	0.25	Fine	1.75	2.60	4.62	4.0	2.2	5.0
	0.40	Coarse	1.60
2.2	0.25	Fine	1.95	2.80
	0.45	Coarse	1.75
2.5	0.35	Fine	2.15	3.10	5.77	5.0	2.7	6.0
	0.45	Coarse	2.05
3	0.35	Fine	2.65	3.60	6.35	5.5	3.2	7.0
	0.50	Coarse	2.50
3.5	0.35	Fine	3.15	4.20	6.93	6.0	3.7	8.0
	0.60	Coarse	2.90
4	0.50	Fine	3.50	4.80	8.08	7.0	4.3	9.0
	0.70	Coarse	3.30
4.5	0.50	Fine	4.00	5.30
	0.75	Coarse	3.70
5	0.50	Fine	4.50	5.80	9.24	8.0	5.3	10
	0.80	Coarse	4.20
6	0.75	Fine	5.25	7.00	11.5	10	6.4	12
	1.00	Coarse	5.00
7	0.75	Fine	6.25	8.00
	1.00	Coarse	6.00
8	0.75	Fine	7.25	10.00	15.0	13	8.4	16
	1.00	Fine	7.50
	1.25	Coarse	6.80
9	0.75	Fine	8.25	10.50
	1.00	Fine	8.00
	1.25	Coarse	7.80
10	0.75	Fine	9.25	12.00	17.3	15	10.5	20
	1.00	Fine	9.00
	1.25	Fine	8.80
	1.50	Coarse	8.50
11	0.75	Fine	10.25	13.00
	1.00	Fine	10.00
	1.50	Coarse	9.50
12	1.00	Fine	11.00	15.00
	1.25	Fine	10.75
	1.50	Fine	10.50
	1.75	Coarse	10.20
14	1.00	Fine	13.00	17.00
	1.25	Fine	12.80
	1.50	Fine	12.50
	2.00	Coarse	12.00
15	1.00	Fine	14.00	18.00
	1.50	Fine	13.50
16	1.00	Fine	15.00	19.00
	1.50	Fine	14.50
	2.00	Coarse	14.00
17	1.00	Fine	16.00	20.00
	1.50	Fine	15.50
18	1.00	Fine	17.00	21.00
	1.50	Fine	16.50
	2.00	Fine	16.00
	2.50	Coarse	15.50
20	1.00	Fine	19.00	24.00
	1.50	Fine	18.50
	2.00	Fine	18.00
	2.50	Coarse	17.50
22	1.00	Fine	21.00	26.00
	1.50	Fine	20.50
	2.00	Fine	20.00
	2.50	Coarse	19.50
24	1.00	Fine	23.00	28.00
	1.50	Fine	22.50
	2.00	Fine	22.00
	3.00	Coarse	21.00
25	1.00	Fine	24.00	30.00
	1.50	Fine	23.50
	2.00	Fine	23.00
26	1.50	Fine	24.50
27	1.00	Fine	26.00	32.00
	1.50	Fine	25.50
	2.00	Fine	25.00
	3.00	Coarse	24.00
28	1.00	Fine	27.00
	1.50	Fine	26.50
	2.00	Fine	26.00
30	1.00	Fine	29.00	35.00
	1.50	Fine	28.50
	2.00	Fine	28.00
	3.00	Fine	27.00
	3.50	Coarse	26.50
32	1.50	Fine	30.50
	2.00	Fine	30.00
33	1.50	Fine	31.50	38.00
	2.00	Fine	31.00
	3.00	Fine	30.00
	3.50	Coarse	29.50
35	1.50	Fine	33.50
	2.00	Fine	33.00
36	1.50	Fine	34.50	42.00
	2.00	Fine	34.00
	3.00	Fine	33.00
	4.00	Coarse	32.00
39	1.50	Fine	37.50	45.00
	2.00	Fine	37.00
	3.00	Fine	36.00
	4.00	Coarse	35.00
40	1.50	Fine	38.50
	2.00	Fine	38.00
	3.00	Fine	37.00
42	1.50	Fine	40.50	48.00
	2.00	Fine	40.00
	3.00	Fine	39.00
	4.00	Fine	38.00
	4.50	Coarse	37.50
45	1.50	Fine	43.50	52.00
	2.00	Fine	43.00
	3.00	Fine	42.00
	4.00	Fine	41.00
	4.50	Coarse	40.50
48	1.50	Fine	46.50	56.00
	2.00	Fine	46.00
	3.00	Fine	45.00
	4.00	Fine	44.00
	5.00	Coarse	43.00
50	1.50	Fine	48.50
	2.00	Fine	48.00
	3.00	Fine	47.00
52	1.50	Fine	50.50	62.00
	2.00	Fine	50.00
	3.00	Fine	49.00
	4.00	Fine	48.00
	5.00	Coarse	47.00
55	1.50	Fine	53.50
	2.00	Fine	53.00
	3.00	Fine	52.00
	4.00	Fine	51.00
56	1.50	Fine	54.50	66.00
	2.00	Fine	54.00
	3.00	Fine	53.00
	4.00	Fine	52.00
	5.50	Coarse	50.50

1) See Drill Sizes page for cross reference.
2) Nut Points is the distance between opposite corners of hex nuts.
3) Nut Flats is the distance between opposite sides of hex nuts.

Webmaster: Kirt Blattenberger, BSEE, UVM 1989