U.S. and Metric Fasteners - Thread Sizes

Compare and analyze U.S. and Metric fastener thread sizes. This tool provides detailed technical data for threading specifications in both imperial and metric standards, essential for engineers and designers working with fasteners.

Fastener Type	U.S. Thread Size	Metric Thread Size	Pitch (mm)	Major Diameter (mm)
Bolt	#0-80	M1.6	0.35	1.6
Bolt	#1-64	M1.8	0.35	1.8
Bolt	#2-56	M2.2	0.40	2.2
Bolt	#3-48	M2.5	0.45	2.5
Bolt	#4-40	M2.8	0.40	2.8
Bolt	#5-40	M3.2	0.35	3.2
Bolt	#6-32	M3.5	0.60	3.5
Bolt	#8-32	M4.2	0.70	4.2
Bolt	#10-24	M5.1	0.80	5.1
Bolt	#12-24	M5.8	0.75	5.8
Bolt	1/4"-20	M6.3	1.00	6.3
Bolt	5/16"-18	M8.0	1.25	8.0
Bolt	3/8"-16	M9.5	1.50	9.5
Bolt	7/16"-14	M11.0	1.50	11.0
Bolt	1/2"-13	M12.0	1.75	12.0
Bolt	9/16"-12	M14.0	2.00	14.0
Bolt	5/8"-11	M16.0	2.00	16.0