Flange Tables

If you work in maintenance, projects, or procurement, our flange tables will help you identify unknown flanges from simple measurements.

Use the steps and tables to match your flange’s dimensions, including the outer diameter (OD), pitch circle diameter (PCD), bolt count and bolt size.

Once you know the standard and class, you can specify compatible valves, gaskets, and fittings. This guide covers common AS 4087, AS 2129, ANSI/ASME B16.5, and ISO 7005 (DIN) flange sizes.

Flange size reference: Identify your flange fast in our flange tables

Flange Dimensions

15mm (1/2")

Standard	Class	Diameter	Bolt Circle Diameter	Number of Bolts	Bolt Size	Diameter of Bolt Hole
AS 4087	PN14	95	67	4	M12	14
AS 2129	Table C	95	67	4	M12	14
	Table D	95	67	4	M12	14
	Table E	95	67	4	M12	14
	Table F	95	67	4	M12	14
	Table H	114	83	4	M16	17
	Table J	114	83	4	M16	17
ANSI B16.5	ANSI 150	89	60	4	13	16
	ANSI 300	95	67	4	13	16
	ANSI 600	95	67	4	13	16
	ANSI 900	121	83	4	19	22
	ANSI 1500	121	83	4	19	22
ISO 7005 (DIN)	PN6	80	55	4	M10	11
	PN10	95	65	4	M12	14
	PN16	95	65	4	M12	14
	PN20	90	60.5	4	M14	16
	PN25	95	65	4	M12	14
	PN40	95	65	4	M12	14

20mm (3/4")

Standard	Class	Diameter	Bolt Circle Diameter	Number of Bolts	Bolt Size	Diameter of Bolt Hole
AS 4087	PN14	100	73	4	M12	14
AS 2129	Table C	100	73	4	M12	14
	Table D	100	73	4	M12	14
	Table E	100	73	4	M12	14
	Table F	100	73	4	M12	14
	Table H	115	83	4	M12	18
	Table J	115	83	4	M12	18
ANSI B16.5	ANSI 150	98	70	4	13	16
	ANSI 300	117	83	4	16	19
	ANSI 600	117	83	4	16	19
	ANSI 900	130	89	4	19	22
	ANSI 1500	130	89	4	19	22
ISO 7005 (DIN)	PN6	90	65	4	M10	11
	PN10	105	75	4	M12	14
	PN16	105	75	4	M12	14
	PN20	100	70	4	M14	16
	PN25	105	75	4	M12	14
	PN40	105	75	4	M12	14

25mm (1")

Standard	Class	Diameter	Bolt Circle Diameter	Number of Bolts	Bolt Size	Diameter of Bolt Hole
AS 4087	PN14	115	83	4	M12	14
AS 2129	Table C	115	83	4	M12	14
	Table D	115	83	4	M12	14
	Table E	115	83	4	M12	14
	Table F	120	87	4	M16	18
	Table H	120	87	4	M16	18
	Table J	120	87	4	M16	18
ANSI B16.5	ANSI 150	110	79	4	13	16
	ANSI 300	125	89	4	16	19
	ANSI 600	125	89	4	16	19
	ANSI 900		102	4	22	25
	ANSI 1500		102	4	22	25
ISO 7005 (DIN)	PN6	100	78	4	M10	11
	PN10	115	85	4	M12	14
	PN16	115	85	4	M12	14
	PN20	110	79.5	4	M14	16
	PN25	115	85	4	M12	14
	PN40	115	85	4	M12	14

32mm (1 1/4")

Standard	Class	Diameter	Bolt Circle Diameter	Number of Bolts	Bolt Size	Diameter of Bolt Hole
AS 4087	PN14	120	87	4	M12	14
AS 2129	Table C	120	87	4	M12	14
	Table D	120	87	4	M12	14
	Table E	120	87	4	M12	14
	Table F	135	98	4	M16	18
	Table H	135	98	4	M16	18
	Table J	135	98	4	M16	18
ANSI B16.5	ANSI 150	117	89	4	13	16
	ANSI 300	133	98	4	16	19
	ANSI 600	133	98	4	16	19
	ANSI 900	159	111	4	22	25
	ANSI 1500	159	111	4	22	25
ISO 7005 (DIN)	PN6	120	90	4	M12	14
	PN10	140	100	4	M16	18
	PN16	140	100	4	M16	18
	PN20	120	89	4	M14	16
	PN25	140	100	4	M16	18
	PN40	140	100	4	M16	18

40mm (1 1/2")

Standard	Class	Diameter	Bolt Circle Diameter	Number of Bolts	Bolt Size	Diameter of Bolt Hole
AS 4087	PN14	135	98	4	M12	14
AS 2129	Table C	135	98	4	M12	14
	Table D	135	98	4	M12	14
	Table E	135	98	4	M12	14
	Table F	140	105	4	M16	18
	Table H	140	105	4	M16	18
	Table J	140	105	4	M16	18
ANSI B16.5	ANSI 150	127	98	4	13	16
	ANSI 300	156	114	4	19	22
	ANSI 600	156	114	4	19	22
	ANSI 900	178	124	4	25	29
	ANSI 1500	178	124	4	25	29
ISO 7005 (DIN)	PN6	130	100	4	M12	14
	PN10	150	110	4	M16	18
	PN16	150	110	4	M16	18
	PN20	130	98.5	4	M14	16
	PN25	150	110	4	M16	18
	PN40	150	110	4	M16	18

50mm (2")

Standard	Class	Diameter	Bolt Circle Diameter	Number of Bolts	Bolt Size	Diameter of Bolt Hole
AS 4087	PN14	150	114	4	M16	18
	PN16	150	114	4	M16	18
	PN21	165	127	4	M16	18
	PN35	165	127	4	M16	18
AS 2129	Table C	150	114	4	M16	18
	Table D	150	114	4	M16	18
	Table E	150	114	4	M16	18
	Table F	165	127	4	M16	18
	Table H	165	127	4	M16	18
	Table J	165	127	4	M20	22
ANSI B16.5	ANSI 150	152	121	4	16	19
	ANSI 300	165	127	8	16	19
	ANSI 600	165	127	8	16	19
	ANSI 900	216	165	8	22	25
	ANSI 1500	216	165	8	22	25
ISO 7005 (DIN)	PN6	140	110	4	M12	14
	PN10	165	125	4	M16	18
	PN16	165	125	4	M16	18
	PN20	150*	120.5	4	M16	18
	PN25	165	125	4	M16	18
	PN40	165	125	4	M16	18
*When made from cast or ductile iron the OD is 155mm.

65mm (2 1/2")

Standard	Class	Diameter	Bolt Circle Diameter	Number of Bolts	Bolt Size	Diameter of Bolt Hole
AS 4087	PN14	165	127	4	M16	18
	PN16	165	127	4	M16	18
	PN21	185	146	8	M16	18
	PN35	185	146	8	M16	18
AS 2129	Table C	165	127	4	M16	18
	Table D	165	127	4	M16	18
	Table E	165	127	4	M16	18
	Table F	185	146	8	M16	18
	Table H	185	146	8	M16	18
	Table J	185	146	8	M20	22
ANSI B16.5	ANSI 150	178	140	4	16	19
	ANSI 300	191	149	8	19	22
	ANSI 600	191	149	8	19	22
	ANSI 900	244	191	8	22	25
	ANSI 1500	244	191	8	25	29
ISO 7005 (DIN)	PN6	160	130	4	M12	14
	PN10	185	145	4	M16	18
	PN16	185	145	4	M16	18
	PN20	180	139.5	4	M16	18
	PN25	185	145	8	M16	18
	PN40	185	145	8	M16	18

80mm (3")

Standard	Class	Diameter	Bolt Circle Diameter	Number of Bolts	Bolt Size	Diameter of Bolt Hole
AS 4087	PN14	185	146	4	M16	18
	PN16	185	146	4	M16	18
	PN21	205	165	8	M16	18
	PN35	205	165	8	M16	18
AS 2129	Table C	185	146	4	M16	18
	Table D	185	146	4	M16	18
	Table E	185	146	4	M16	18
	Table F	205	165	8	M16	18
	Table H	205	165	8	M16	18
	Table J	205	165	8	M20	22
ANSI B16.5	ANSI 150	191	152	4	16	19
	ANSI 300	210	168	8	19	22
	ANSI 600	210	168	8	19	22
	ANSI 900	241	192	8	22	25
	ANSI 1500	267	203	8	29	32
ISO 7005 (DIN)	PN6	190	150	4	M16	18
	PN10	200	160	8	M16	18
	PN16	200	160	8	M16	18
	PN20	190	152.5	4	M16	18
	PN25	200	160	8	M16	18
	PN40	200	160	8	M16	18

100mm (4")

Standard	Class	Diameter	Bolt Circle Diameter	Number of Bolts	Bolt Size	Diameter of Bolt Hole
AS 4087	PN14	215	178	4	M16	18
	PN16	215	178	4	M16	18
	PN21	230	191	8	M16	18
	PN35	230	191	8	M16	18
AS 2129	Table C	215	178	4	M16	18
	Table D	215	178	4	M16	18
	Table E	215	178	8	M16	18
	Table F	230	191	8	M16	18
	Table H	230	191	8	M16	18
	Table J	230	191	8	M20	22
ANSI B16.5	ANSI 150	229	191	8	16	19
	ANSI 300	254	200	8	19	22
	ANSI 600	273	216	8	22	25
	ANSI 900	292	235	8	29	32
	ANSI 1500	311	241	8	32	35
ISO 7005 (DIN)	PN6	210	170	4	M16	18
	PN10	220	180	8	M16	24
	PN16	220	180	8	M16	18
	PN20	230	190.5	8	M16	18
	PN25	235	190	8	M20	22
	PN40	235	190	8	M20	22

125mm (5")

Standard	Class	Diameter	Bolt Circle Diameter	Number of Bolts	Bolt Size	Diameter of Bolt Hole
AS 4087	PN14	255	210	8	M16	18
	PN16	255	210	8	M16	18
	PN21	280	235	8	M20	22
	PN35	280	235	8	M20	22
AS 2129	Table C	255	210	8	M16	18
	Table D	255	210	8	M16	18
	Table E	255	210	8	M16	18
	Table F	280	235	8	M20	22
	Table H	280	235	8	M20	22
	Table J	280	235	8	M24	26
ANSI B16.5	ANSI 150	254	216	8	19	22
	ANSI 300	279	235	8	19	22
	ANSI 600	330	267	8	25	29
	ANSI 900	349	279	8	32	35
	ANSI 1500	375	292	8	38	41
ISO 7005 (DIN)	PN6	240	200	8	M16	18
	PN10	250	210	8	M16	18
	PN16	250	210	8	M16	18
	PN20	255	216	8	M20	22
	PN25	270	220	8	M24	26
	PN40	270	220	8	M24	26

150mm (6")

Standard	Class	Diameter	Bolt Circle Diameter	Number of Bolts	Bolt Size	Diameter of Bolt Hole
AS 4087	PN14	280	235	8	M16	18
	PN16	280	235	8	M16	18
	PN21	305	260	12	M20	22
	PN35	305	260	12	M20	22
AS 2129	Table C	280	235	8	M16	18
	Table D	280	235	8	M16	18
	Table E	280	235	8	M20	22
	Table F	305	260	12	M20	22
	Table H	305	260	12	M20	22
	Table J	305	260	12	M24	26
ANSI B16.5	ANSI 150	279	241	8	19	22
	ANSI 300	318	270	12	19	22
	ANSI 600	356	292	12	25	29
	ANSI 900	381	318	12	29	32
	ANSI 1500	394	318	12	35	38
ISO 7005 (DIN)	PN6	265	225	8	M16	18
	PN10	285	240	8	M20	22
	PN16	285	240	8	M20	22
	PN20	280	241.5	8	M20	22
	PN25	300	250	8	M24	26
	PN40	300	250	8	M24	26

200mm (8")

Standard	Class	Diameter	Bolt Circle Diameter	Number of Bolts	Bolt Size	Diameter of Bolt Hole
AS 4087	PN14	335	292	8	M16	18
	PN16	335	292	8	M16	18
	PN21	370	324	12	M20	22
	PN35	370	324	12	M20	22
AS 2129	Table C	335	292	8	M16	18
	Table D	335	292	8	M16	18
	Table E	335	292	8	M20	22
	Table F	370	324	12	M20	22
	Table H	370	324	12	M20	22
	Table J	370	324	12	M24	26
ANSI B16.5	ANSI 150	343	298	8	19	22
	ANSI 300	381	330	12	19	22
	ANSI 600	419	349	12	29	32
	ANSI 900	470	394	12	35	38
	ANSI 1500	483	394	12	41	44
ISO 7005 (DIN)	PN6	320	280	8	M16	18
	PN10	340	295	8	M20	22
	PN16	340	295	12	M20	22
	PN20	345	298.5	8	M20	22
	PN25	360	310	12	M24	26
	PN40	375	320	12	M27	30

250mm (10")

Standard	Class	Diameter	Bolt Circle Diameter	Number of Bolts	Bolt Size	Diameter of Bolt Hole
AS 4087	PN14	405	356	8	M20	22
	PN16	405	356	8	M20	22
	PN21	430	381	12	M24	26
	PN35	430	381	12	M24	26
AS 2129	Table C	405	356	8	M20	22
	Table D	405	356	8	M20	22
	Table E	405	356	12	M20	22
	Table F	430	381	12	M24	26
	Table H	430	381	12	M24	26
	Table J	430	381	12	M27	30
ANSI B16.5	ANSI 150	406	362	12	22	25
	ANSI 300	445	387	16	25	29
	ANSI 600	508	432	16	32	35
	ANSI 900	546	470	16	35	38
	ANSI 1500	584	483	12	41	51
ISO 7005 (DIN)	PN6	375	335	12	M16	18
	PN10	395	350	12	M20	22
	PN16	405	355	12	M24	26
	PN20	405	362	12	M24	26
	PN25	425	370	12	M27	30
	PN40	450	385	12	M30	33

300mm (12")

Standard	Class	Diameter	Bolt Circle Diameter	Number of Bolts	Bolt Size	Diameter of Bolt Hole
AS 4087	PN14	455	406	12	M20	22
	PN16	455	406	12	M20	22
	PN21	490	438	16	M24	26
	PN35	490	438	16	M24	26
AS 2129	Table C	455	406	12	M20	22
	Table D	455	406	12	M20	22
	Table E	455	406	12	M24	26
	Table F	490	438	16	M24	26
	Table H	490	438	16	M24	26
	Table J	490	438	16	M27	30
ANSI B16.5	ANSI 150	483	432	12	22	25
	ANSI 300	521	451	16	29	32
	ANSI 600	559	489	20	32	35
	ANSI 900	610	533	20	35	38
	ANSI 1500	673	571	16	51	54
ISO 7005 (DIN)	PN6	440	395	12	M20	22
	PN10	445	400	12	M20	22
	PN16	460	410	12	M24	26
	PN20	485	432	12	M24	26
	PN25	485	430	16	M27	30
	PN40	515	450	16	M30	33

350mm (14")

Standard	Class	Diameter	Bolt Circle Diameter	Number of Bolts	Bolt Size	Diameter of Bolt Hole
AS 4087	PN14	525	470	12	M24	26
	PN16	525	470	12	M24	26
	PN21	550	495	16	M27	30
	PN35	550	495	16	M27	30
AS 2129	Table C	525	470	12	M24	26
	Table D	525	470	12	M24	26
	Table E	525	470	12	M24	26
	Table F	550	495	16	M27	30
	Table H	550	495	16	M27	30
	Table J	550	495	16	M30	32
ANSI B16.5	ANSI 150	533	476	12	25	29
	ANSI 300	584	514	20	29	32
	ANSI 600	603	527	20	38	41
	ANSI 900	641	559	20	38	41
	ANSI 1500	749	635	16	57	60
ISO 7005 (DIN)	PN6	490	445	12	M20	22
	PN10	505	460	16	M20	22
	PN16	520	470	16	M24	26
	PN20	535	476	12	M27	35
	PN25	555	490	16	M30	33
	PN40	580	510	16	M33	36

400mm (16")

Standard	Class	Diameter	Bolt Circle Diameter	Number of Bolts	Bolt Size	Diameter of Bolt Hole
AS 4087	PN14	580	521	12	M24	26
	PN16	580	521	12	M24	26
	PN21	610	552	20	M27	30
	PN35	610	552	20	M27	30
AS 2129	Table C	580	521	12	M24	26
	Table D	580	521	12	M24	26
	Table E	580	521	12	M24	26
	Table F	610	552	20	M27	30
	Table H	610	552	20	M27	30
	Table J	610	552	20	M30	33
ANSI B16.5	ANSI 150	597	540	16	1" (M24)	29
	ANSI 300	648	572	20	1-1/4" (M30)	35
	ANSI 600	686	603	20	1-1/2" (M36)	41
	ANSI 900	705	616	20	1-5/8" (M42)	44
	ANSI 1500	826	705	16	2-1/2" (M64)	67
ISO 7005 (DIN)	PN6	540	495	16	M20	22
	PN10	565	515	16	M24	26
	PN16	580	525	16	M27	30
	PN20	600	540	16	M27	29.5
	PN25	620	550	16	M33	36
	PN40	660	585	16	M36	39

450mm (18")

Standard	Class	Diameter	Bolt Circle Diameter	Number of Bolts	Bolt Size	Diameter of Bolt Hole
AS 4087	PN14 Flange	640	584	12	M24	26
	PN16 Flange	640	584	12	M24	26
	PN21 Flange	675	610	20	M30	33
	PN35 Flange	675	510	20	M30	33
AS 2129	Table C Flange	640	584	12	M24	26
	Table D Flange	640	584	12	M24	26
	Table E Flange	640	584	16	M24	26
	Table F Flange	675	610	20	M30	33
	Table H Flange	675	610	20	M30	33
	Table J Flange	675	610	20	M33	36
ANSI B16.5	ANSI 150 Flange	635	578	16	1-1/8" (M27)	32
	ANSI 300 Flange	711	629	24	1-1/4" (M30)	35
	ANSI 600 Flange	743	654	20	1-5/8" (M42)	44
	ANSI 900 Flange	787	686	20	1-7/8" (M48)	51
	ANSI 1500 Flange	914	775	16	2-3/4" (M72)	73
ISO 7005 (DIN)	PN6 Flange	595	550	16	M20	22
	PN10 Flange	615	565	20	M24	26
	PN16 Flange	640	585	20	M27	30
	PN20 Flange	635	578	16	M30	32.5
	PN25 Flange	-	-	-	-	-
	PN40 Flange	-	-	-	-	-

500mm (20")

Standard	Class	Diameter	Bolt Circle Diameter	Number of Bolts	Bolt Size	Diameter of Bolt Hole
AS 4087	PN14 Flange	705	641	16	M24	26
	PN16 Flange	705	641	16	M24	26
	PN21 Flange	735	673	24	M30	33
	PN35 Flange	735	673	24	M30	33
AS 2129	Table C Flange	705	641	16	M24	26
	Table D Flange	705	641	16	M24	26
	Table E Flange	705	641	16	M24	26
	Table F Flange	735	673	24	M30	33
	Table H Flange	735	673	24	M30	33
	Table J Flange	735	673	24	M33	36
ANSI B16.5	ANSI 150 Flange	699	635	20	1-1/8" (M27)	32
	ANSI 300 Flange	775	686	24	1-1/4" (M30)	35
	ANSI 600 Flange	813	724	24	1-5/8" (M42)	44
	ANSI 900 Flange	857	749	20	2" (M48)	54
	ANSI 1500 Flange	984	832	16	3" (M80)	79
ISO 7005 (DIN)	PN6 Flange	645	600	20	M20	22
	PN10 Flange	670	620	20	M24	26
	PN16 Flange	715	650	20	M30	33
	PN20 Flange	700	635	20	M30	32.5
	PN25 Flange	-	-	-	-	-
	PN40 Flange	-	-	-	-	-

600mm (24")

Standard	Class	Diameter	Bolt Circle Diameter	Number of Bolts	Bolt Size	Diameter of Bolt Hole
AS 4087	PN14 Flanges	825	756	16	M27	30
	PN16 Flanges	825	756	16	M27	30
	PN21 Flanges	850	781	24	M33	36
	PN35 Flanges	750	781	24	M33	36
AS 2129	Table C Flanges	825	756	16	M27	30
	Table D Flanges	825	756	16	M27	30
	Table E Flanges	825	756	16	M30	33
	Table F Flanges	850	781	24	M33	36
	Table H Flanges	850	781	24	M33	36
	Table J Flanges	850	781	24	M36	39
ANSI B16.5	ANSI 150 Flanges	813	749	20	1-1/4" (M30)	35
	ANSI 300 Flanges	914	813	24	1-1/2" (M36)	41
	ANSI 600 Flanges	940	838	24	1-7/8" (M48)	51
	ANSI 900 Flanges	1041	902	20	2-1/2" (M64)	67
	ANSI 1500 Flanges	1168	991	16	3-1/2" (M90)	92
ISO 7005 (DIN)	PN6 Flanges	755	705	20	M24	26
	PN10 Flanges	780	725	20	M27	30
	PN16 Flanges	840	770	20	M33	36
	PN20 Flanges	815	749.5	20	M33	36
	PN25 Flanges	-	-	-	-	-
	PN40 Flanges	-	-	-	-	-

How to use this flange size chart (3-step guide)

Measure the outer diameter (OD) of the flange.
Measure the bolt circle diameter (BCD) and count the bolts.
Use the tables below to match OD, BCD, bolt count and bolt size to the matching standard and pressure class.

Example: If your flange OD is 95 mm with 4 × M12 bolts on a 67 mm BCD, it aligns with AS 4087 PN14 at 15 mm (½″) and several AS 2129 Tables at the same size. Use media and service conditions to select the correct class.

What the column headings mean in our flange charts (plain-language)

OD (outer diameter): Total outside diameter of the flange face.

Bolt circle diameter (BCD): Distance between the centres of two opposite bolt holes.

Number of bolts: Total bolt holes in the flange.

Bolt size: Typical bolt diameter used for that standard/size.

Diameter of bolt hole: Actual drilled hole inside the flange.

Tip: When measurements don’t land exactly on a whole number, allow for coating thickness, calliper error, and manufacturing tolerance. Use the closest match across OD + BCD + bolt count + bolt size together.

Where these flange sizes are commonly used

To make scanning easier, each size group below includes typical applications. These are general guides only—always confirm against your plant standard.

15–32 mm (½″–1¼″) – common in instruments and small service lines

Used in: pressure instruments, small control valves, dosing, HVAC coils. Good starting point when you see 4 bolts and small ODs.

40–65 mm (1½″–2½″) – building services and general utilities

Used in: HVAC, compressed air, water ring mains, washdown lines. You’ll see 4–8 bolts depending on class.

80–150 mm (3″–6″) – plant utilities and process services

Used in: water treatment, CIP return, fuel and low-to-medium pressure steam ancillaries. Typically 8–12 bolts at higher classes.

200–300 mm (8″–12″) – distribution mains and process headers

Used in: water/wastewater trunk lines, slurry bypass, larger steam lines (check class/face type carefully).

350–600 mm (14″–24″) – trunk mains and heavy process duties

Used in: municipal water infrastructure, mine dewatering, large condensate/steam distribution (verify drilling pattern and face).

Standards at a glance: key differences to know

AS 4087: Common for water/wastewater in Australia; metric drilling; typically flat-face on cast iron/ductile iron and raised face on steel/stainless.

AS 2129 (Table C–J): Legacy but still widely encountered in older infrastructure and replacement work.

ANSI/ASME B16.5: Imperial-based; prevalent with North American equipment and some process packages; classes 150–1500.

ISO 7005 (DIN): Metric drilling; common with European equipment; pressure classes PN6–PN40.

“PN” = Pressure Nominal. PN16 is nominally rated to 16 bar at reference temperature (actual pressure-temperature ratings vary by material and standard).

FAQs

What do I do if my measurements don’t match exactly?

Use OD, BCD, bolt count and bolt size together. Choose the row with the closest overall fit. Small variance often comes from coating thickness or measurement error.

How many bolts does a PN16 flange typically have?

It varies by size and standard. For example, many PN16 sizes up to 80 mm use 4 bolts; larger sizes commonly use 8 or more. Check the exact size table.

Which standard should I choose for older infrastructure in Australia?

AS 2129 Tables are common in older plants, while AS 4087 is common in modern water/wastewater infrastructure. Measure, then match to the correct table and class.

Can I swap between ANSI Class 150 and PN16?

Not directly. Drilling patterns and pressure-temperature ratings differ. Verify drilling and gasket seating, or use adaptor flanges.

What does PN mean?

PN stands for “Pressure Nominal”. PN16 indicates nominal 16 bar at a reference temperature; verify against the material’s temperature-pressure curve.