Propane pipe sizing chart and calculator

Pick the system pressure and the material, list the appliances and enter the longest run. You get the propane line size, and below it the full capacity charts for every size and length.

IFGC 402.4 propane tablesUndiluted propane, specific gravity 1.50Longest-length method

Inputs

System pressure

11 in. w.c. (low pressure) 2 psi 10 psi first stage

Pipe or tubing

Sch 40 steel Copper tubing PE (underground)

Appliances on this section

Use the input rating on each appliance's nameplate. The four rows are examples.

Length of the longest run

From the regulator to the farthest appliance on this system.

Result

Line size for — BTU/h

—

Every size at 50 ft, low pressure

Size	ID, in	MBH

Capacity in thousands of BTU per hour (MBH) of undiluted propane, specific gravity 1.50, by the length of the longest run. Copper sizes are K and L nominal, with the outside diameter (the size soft copper and ACR tubing are sold by) underneath. PE is IPS pipe, SDR as shown.

Propane low pressure pipe sizing chart: 11.0 in. w.c. inlet, 0.5 in. w.c. drop

The pressure most propane piping runs at: 11 in. w.c. leaving the second-stage regulator, sized for a 0.5 in. w.c. drop to the farthest appliance.

Schedule 40 steel pipe, low pressure

Length	1/2 in	3/4 in	1 in	1-1/4 in	1-1/2 in	2 in	2-1/2 in	3 in	4 in
10 ft	291	608	1,150	2,350	3,520	6,790	10,800	19,100	39,000
20 ft	200	418	787	1,620	2,420	4,660	7,430	13,100	26,800
30 ft	160	336	632	1,300	1,940	3,750	5,970	10,600	21,500
40 ft	137	287	541	1,110	1,660	3,210	5,110	9,030	18,400
50 ft	122	255	480	985	1,480	2,840	4,530	8,000	16,300
60 ft	110	231	434	892	1,340	2,570	4,100	7,250	14,800
70 ft	101	212	400	821	1,230	2,370	3,770	6,670	13,600
80 ft	94.4	197	372	763	1,140	2,200	3,510	6,210	12,700
90 ft	88.6	185	349	716	1,070	2,070	3,290	5,820	11,900
100 ft	83.7	175	330	677	1,010	1,950	3,110	5,500	11,200
125 ft	74.2	155	292	600	899	1,730	2,760	4,880	9,950
150 ft	67.2	140	265	543	814	1,570	2,500	4,420	9,010
175 ft	61.8	129	243	500	749	1,440	2,300	4,060	8,290
200 ft	57.5	120	227	465	697	1,340	2,140	3,780	7,710
250 ft	51	107	201	412	618	1,190	1,900	3,350	6,840
300 ft	46.2	96.6	182	373	560	1,080	1,720	3,040	6,190
350 ft	42.5	88.8	167	344	515	991	1,580	2,790	5,700
400 ft	39.5	82.6	156	320	479	922	1,470	2,600	5,300
450 ft	37.1	77.5	146	300	449	865	1,380	2,440	4,970
500 ft	35	73.2	138	283	424	817	1,300	2,300	4,700

Semirigid copper tubing (K or L), low pressure

Length	1/4 in 3/8 OD	3/8 in 1/2 OD	1/2 in 5/8 OD	5/8 in 3/4 OD	3/4 in 7/8 OD	1 in 1-1/8 OD
10 ft	44.9	92.5	188	329	467	997
20 ft	30.8	63.6	129	226	321	685
30 ft	24.8	51.1	104	182	258	550
40 ft	21.2	43.7	88.9	155	220	471
50 ft	18.8	38.7	78.8	138	195	417
60 ft	17	35.1	71.4	125	177	378
70 ft	15.7	32.3	65.7	115	163	348
80 ft	14.6	30	61.1	107	152	324
90 ft	13.7	28.2	57.3	100	142	304
100 ft	12.9	26.6	54.2	94.7	134	287
125 ft	11.4	23.6	48	83.9	119	254
150 ft	10.4	21.4	43.5	76	108	230
175 ft	9.53	19.7	40	69.9	99.2	212
200 ft	8.87	18.3	37.2	65.1	92.3	197
250 ft	7.86	16.2	33	57.7	81.8	175
300 ft	7.12	14.7	29.9	52.3	74.1	158
350 ft	6.55	13.5	27.5	48.1	68.2	146
400 ft	6.1	12.6	25.6	44.7	63.4	136
450 ft	5.72	11.8	24	42	59.5	127
500 ft	5.4	11.1	22.7	39.6	56.2	120

Polyethylene (PE) pipe, underground, low pressure

Length	1/2 in SDR 9.33	3/4 in SDR 11	1 in SDR 11	1-1/4 in SDR 10	1-1/2 in SDR 11	2 in SDR 11
10 ft	340	680	1,230	2,130	3,210	5,770
20 ft	233	468	844	1,460	2,210	3,970
30 ft	187	375	677	1,170	1,770	3,180
40 ft	160	321	580	1,000	1,520	2,730
50 ft	142	285	514	890	1,340	2,420
60 ft	129	258	466	807	1,220	2,190
70 ft	119	237	428	742	1,120	2,010
80 ft	110	221	398	690	1,040	1,870
90 ft	103	207	374	648	978	1,760
100 ft	97.8	196	353	612	924	1,660
125 ft	86.6	173	313	542	819	1,470
150 ft	78.5	157	284	491	742	1,330
175 ft	72.2	145	261	452	683	1,230
200 ft	67.2	135	243	420	635	1,140
250 ft	59.5	119	215	373	563	1,010
300 ft	54	108	195	338	510	916
350 ft	49.6	99.4	179	311	469	843
400 ft	46.2	92.5	167	289	436	784
450 ft	43.3	86.7	157	271	409	736
500 ft	40.9	81.9	148	256	387	695

Propane 2 psi pipe sizing chart: 2.0 psi inlet, 1.0 psi drop

For a 2 psi system: the 2 psi regulator to each line-pressure regulator, with a 1 psi drop. Size the piping after each line-pressure regulator with the low-pressure charts.

Schedule 40 steel pipe, 2 psi

Length	1/2 in	3/4 in	1 in	1-1/4 in	1-1/2 in	2 in	2-1/2 in	3 in	4 in
10 ft	2,680	5,590	10,500	21,600	32,400	62,400	99,500	176,000	359,000
20 ft	1,840	3,850	7,240	14,900	22,300	42,900	68,400	121,000	247,000
30 ft	1,480	3,090	5,820	11,900	17,900	34,500	54,900	97,100	198,000
40 ft	1,260	2,640	4,980	10,200	15,300	29,500	47,000	83,100	170,000
50 ft	1,120	2,340	4,410	9,060	13,600	26,100	41,700	73,700	150,000
60 ft	1,010	2,120	4,000	8,210	12,300	23,700	37,800	66,700	136,000
70 ft	934	1,950	3,680	7,550	11,300	21,800	34,700	61,400	125,000
80 ft	869	1,820	3,420	7,030	10,500	20,300	32,300	57,100	117,000
90 ft	815	1,700	3,210	6,590	9,880	19,000	30,300	53,600	109,000
100 ft	770	1,610	3,030	6,230	9,330	18,000	28,600	50,600	103,000
125 ft	682	1,430	2,690	5,520	8,270	15,900	25,400	44,900	91,500
150 ft	618	1,290	2,440	5,000	7,490	14,400	23,000	40,700	82,900
175 ft	569	1,190	2,240	4,600	6,890	13,300	21,200	37,400	76,300
200 ft	529	1,110	2,080	4,280	6,410	12,300	19,700	34,800	71,000
250 ft	469	981	1,850	3,790	5,680	10,900	17,400	30,800	62,900
300 ft	425	889	1,670	3,440	5,150	9,920	15,800	27,900	57,000
350 ft	391	817	1,540	3,160	4,740	9,120	14,500	25,700	52,400
400 ft	364	760	1,430	2,940	4,410	8,490	13,500	23,900	48,800
450 ft	341	714	1,340	2,760	4,130	7,960	12,700	22,400	45,800
500 ft	322	674	1,270	2,610	3,910	7,520	12,000	21,200	43,200

Semirigid copper tubing (K or L), 2 psi

Length	1/4 in 3/8 OD	3/8 in 1/2 OD	1/2 in 5/8 OD	5/8 in 3/4 OD	3/4 in 7/8 OD	1 in 1-1/8 OD
10 ft	413	852	1,730	3,030	4,300	9,180
20 ft	284	585	1,190	2,080	2,950	6,310
30 ft	228	470	956	1,670	2,370	5,060
40 ft	195	402	818	1,430	2,030	4,330
50 ft	173	357	725	1,270	1,800	3,840
60 ft	157	323	657	1,150	1,630	3,480
70 ft	144	297	605	1,060	1,500	3,200
80 ft	134	276	562	983	1,390	2,980
90 ft	126	259	528	922	1,310	2,790
100 ft	119	245	498	871	1,240	2,640
125 ft	105	217	442	772	1,100	2,340
150 ft	95.4	197	400	700	992	2,120
175 ft	87.7	181	368	644	913	1,950
200 ft	81.6	168	343	599	849	1,810
250 ft	72.3	149	304	531	753	1,610
300 ft	65.5	135	275	481	682	1,460
350 ft	60.3	124	253	442	628	1,340
400 ft	56.1	116	235	412	584	1,250
450 ft	52.6	109	221	386	548	1,170
500 ft	49.7	103	209	365	517	1,110

Polyethylene (PE) pipe, underground, 2 psi

Length	1/2 in SDR 9.33	3/4 in SDR 11	1 in SDR 11	1-1/4 in SDR 10	1-1/2 in SDR 11	2 in SDR 11
10 ft	3,130	6,260	11,300	19,600	29,500	53,100
20 ft	2,150	4,300	7,760	13,400	20,300	36,500
30 ft	1,730	3,450	6,230	10,800	16,300	29,300
40 ft	1,480	2,960	5,330	9,240	14,000	25,100
50 ft	1,310	2,620	4,730	8,190	12,400	22,200
60 ft	1,190	2,370	4,280	7,420	11,200	20,100
70 ft	1,090	2,180	3,940	6,830	10,300	18,500
80 ft	1,010	2,030	3,670	6,350	9,590	17,200
90 ft	952	1,910	3,440	5,960	9,000	16,200
100 ft	899	1,800	3,250	5,630	8,500	15,300
125 ft	797	1,600	2,880	4,990	7,530	13,500
150 ft	722	1,450	2,610	4,520	6,830	12,300
175 ft	665	1,330	2,400	4,160	6,280	11,300
200 ft	618	1,240	2,230	3,870	5,840	10,500
250 ft	548	1,100	1,980	3,430	5,180	9,300
300 ft	496	994	1,790	3,110	4,690	8,430
350 ft	457	914	1,650	2,860	4,320	7,760
400 ft	425	851	1,530	2,660	4,020	7,220
450 ft	399	798	1,440	2,500	3,770	6,770
500 ft	377	754	1,360	2,360	3,560	6,390

Propane first stage pipe sizing chart: 10.0 psi inlet, 1.0 psi drop

The line from the first-stage regulator at the tank to the second-stage regulator at the building: 10 psi with a 1 psi drop.

Schedule 40 steel pipe, first stage

Length	1/2 in	3/4 in	1 in	1-1/4 in	1-1/2 in	2 in	2-1/2 in	3 in	4 in
10 ft	3,320	6,950	13,100	26,900	40,300	77,600	124,000	219,000	446,000
20 ft	2,280	4,780	9,000	18,500	27,700	53,300	85,000	150,000	306,000
30 ft	1,830	3,840	7,230	14,800	22,200	42,800	68,200	121,000	246,000
40 ft	1,570	3,280	6,180	12,700	19,000	36,600	58,400	103,000	211,000
50 ft	1,390	2,910	5,480	11,300	16,900	32,500	51,800	91,500	187,000
60 ft	1,260	2,640	4,970	10,200	15,300	29,400	46,900	82,900	169,000
70 ft	1,160	2,430	4,570	9,380	14,100	27,100	43,100	76,300	156,000
80 ft	1,080	2,260	4,250	8,730	13,100	25,200	40,100	70,900	145,000
90 ft	1,010	2,120	3,990	8,190	12,300	23,600	37,700	66,600	136,000
100 ft	956	2,000	3,770	7,730	11,600	22,300	35,600	62,900	128,000
125 ft	848	1,770	3,340	6,850	10,300	19,800	31,500	55,700	114,000
150 ft	768	1,610	3,020	6,210	9,300	17,900	28,600	50,500	103,000
175 ft	706	1,480	2,780	5,710	8,560	16,500	26,300	46,500	94,700
200 ft	657	1,370	2,590	5,320	7,960	15,300	24,400	43,200	88,100
250 ft	583	1,220	2,290	4,710	7,060	13,600	21,700	38,300	78,100
300 ft	528	1,100	2,080	4,270	6,400	12,300	19,600	34,700	70,800
350 ft	486	1,020	1,910	3,930	5,880	11,300	18,100	31,900	65,100
400 ft	452	945	1,780	3,650	5,470	10,500	16,800	29,700	60,600
450 ft	424	886	1,670	3,430	5,140	9,890	15,800	27,900	56,800
500 ft	400	837	1,580	3,240	4,850	9,340	14,900	26,300	53,700

Semirigid copper tubing (K or L), first stage

Length	1/4 in 3/8 OD	3/8 in 1/2 OD	1/2 in 5/8 OD	5/8 in 3/4 OD	3/4 in 7/8 OD	1 in 1-1/8 OD
10 ft	513	1,060	2,150	3,760	5,340	11,400
20 ft	352	727	1,480	2,580	3,670	7,830
30 ft	283	584	1,190	2,080	2,940	6,290
40 ft	242	500	1,020	1,780	2,520	5,380
50 ft	215	443	901	1,570	2,230	4,770
60 ft	194	401	816	1,430	2,020	4,320
70 ft	179	369	751	1,310	1,860	3,980
80 ft	166	343	699	1,220	1,730	3,700
90 ft	156	322	655	1,150	1,630	3,470
100 ft	147	304	619	1,080	1,540	3,280
125 ft	131	270	549	959	1,360	2,910
150 ft	118	244	497	869	1,230	2,630
175 ft	109	225	457	799	1,130	2,420
200 ft	101	209	426	744	1,060	2,250
250 ft	89.8	185	377	659	935	2,000
300 ft	81.4	168	342	597	847	1,810
350 ft	74.9	155	314	549	779	1,670
400 ft	69.7	144	292	511	725	1,550
450 ft	65.4	135	274	480	680	1,450
500 ft	61.8	127	259	453	643	1,370

Polyethylene (PE) pipe, underground, first stage

Length	1/2 in SDR 9.33	3/4 in SDR 11	1 in SDR 11	1-1/4 in SDR 10	1-1/2 in SDR 11	2 in SDR 11
10 ft	3,880	7,770	14,000	24,300	36,700	65,900
20 ft	2,670	5,340	9,640	16,700	25,200	45,300
30 ft	2,140	4,290	7,740	13,400	20,300	36,400
40 ft	1,830	3,670	6,630	11,500	17,300	31,100
50 ft	1,630	3,250	5,870	10,200	15,400	27,600
60 ft	1,470	2,950	5,320	9,220	13,900	25,000
70 ft	1,350	2,710	4,900	8,480	12,800	23,000
80 ft	1,260	2,520	4,550	7,890	11,900	21,400
90 ft	1,180	2,370	4,270	7,400	11,200	20,100
100 ft	1,120	2,240	4,040	6,990	10,600	19,000
125 ft	990	1,980	3,580	6,200	9,360	16,800
150 ft	897	1,800	3,240	5,620	8,480	15,200
175 ft	825	1,650	2,980	5,170	7,800	14,000
200 ft	768	1,540	2,770	4,810	7,260	13,000
250 ft	681	1,360	2,460	4,260	6,430	11,600
300 ft	617	1,230	2,230	3,860	5,830	10,500
350 ft	567	1,140	2,050	3,550	5,360	9,630
400 ft	528	1,060	1,910	3,300	4,990	8,960
450 ft	495	991	1,790	3,100	4,680	8,410
500 ft	468	937	1,690	2,930	4,420	7,940

Gas work needs a permit and a qualified installer. The charts follow the IFGC propane tables. Your jurisdiction may adopt NFPA 54 or NFPA 58 instead, or amend the code, and the propane supplier usually sets the regulators. Check the result against the code adopted where you work. CSST is not covered: each brand publishes its own propane table.

How to use the charts

Find the system pressure. Most homes are low pressure: a first-stage regulator at the tank drops it to about 10 psi, and a second-stage regulator at the house drops it to 11 in. w.c. (about 0.4 psi). Some homes run 2 psi inside with a line-pressure regulator at each appliance group.
Measure the longest run: the length of pipe from the regulator at the start of that system to the farthest appliance.
Use the row for that length, or the next longer row, for every section of the system.
Size each section for the appliances downstream of it: read across the row to the first size whose capacity covers their total input.

That is the longest-length method of IFGC 402.4.1. Worked through for a 100,000 BTU/h furnace on Schedule 40 at low pressure: at 50 ft the 1/2 in. column shows 122 MBH, so 1/2 in. is enough; at 80 ft it shows 94.4, so it takes 3/4 in.

How the numbers are worked out

The code's propane tables come from the two sizing equations in IFGC 402.4. The calculator uses them directly:

Low pressure (under 1.5 psi): Q = 2313 × D^2.623 × (ΔH ÷ (Cr × L))^0.541 2 psi and 10 psi: Q = 2237 × D^2.623 × ((P1² − P2²) × Y ÷ (Cr × L))^0.541 Q flow, cfh D inside diameter, in ΔH pressure drop, in. w.c. L length, ft P1, P2 inlet and outlet pressure, psia Cr 1.2462 and Y 0.9910 for undiluted propane (IFGC Table 402.4)

Flow is turned into BTU/h at 2,488 BTU per cubic foot, and the results are rounded to three significant digits as the code tables are. We worked the heating value back from the published tables: with it, the equations reproduce 233 of the 237 published propane table entries we checked exactly, and the other four within one in the last digit. Charts built on the often-quoted 2,516 BTU/ft³ run about 1% higher, and charts that add 50% to the length for fittings run lower. That is why propane charts found online disagree slightly.

Propane against natural gas

The same pipe carries far more heat as propane. Propane is heavier, so less of it flows, but each cubic foot holds about two and a half times the heat. At 10 ft and a 0.5 in. w.c. drop, 1/2 in. Schedule 40 carries about 172 MBH of natural gas (at 1,000 BTU per cubic foot) and 291 MBH of propane. Never use a propane chart for natural gas: the pipe comes out too small. For natural gas use the natural gas pipe sizing calculator.

Questions

How many BTU can a 1/2 inch propane line carry?

At low pressure (11 in. w.c., 0.5 in. w.c. drop), 1/2 in. Schedule 40 steel carries 291 MBH at 10 ft, 200 at 20 ft, 122 at 50 ft and 83.7 at 100 ft. MBH is thousands of BTU per hour.

How many BTU can a 3/4 inch propane line carry?

At low pressure, 3/4 in. Schedule 40 carries 608 MBH at 10 ft, 418 at 20 ft, 255 at 50 ft and 175 at 100 ft.

How many BTU can a 1 inch propane line carry?

At low pressure, 1 in. Schedule 40 carries 1,150 MBH at 10 ft, 787 at 20 ft, 480 at 50 ft and 330 at 100 ft.

What size propane line do I need for a furnace?

For a 100,000 BTU/h furnace on its own, at low pressure in Schedule 40: 1/2 in. at 50 ft, 1/2 in. at 70 ft, 3/4 in. at 80 ft, 3/4 in. at 100 ft. Size the whole system, though: the pipe nearest the regulator carries every appliance, so it is usually bigger than the furnace branch.

What size propane line do I need for a tankless water heater?

A 199,000 BTU/h tankless heater on its own, at low pressure in Schedule 40: 1/2 in. at 20 ft, 3/4 in. at 30 ft, 3/4 in. at 60 ft, 1 in. at 80 ft. Tankless heaters are the reason many propane lines have to be upsized.

Can I use copper tubing for propane?

Yes. Semirigid copper tubing, Type K or L, has its own propane tables. At low pressure, 1/2 in. K/L (5/8 in. OD) carries 129 MBH at 20 ft and 3/4 in. (7/8 in. OD) 321 MBH. Soft copper and ACR tubing are sold by outside diameter, so 3/8 in. soft copper is the 1/4 in. K/L row.

What size line from the propane tank to the house?

That line runs at first-stage pressure, about 10 psi, so it can be small. With a 1 psi drop, 3/8 in. K/L copper (1/2 in. OD) carries 304 MBH at 100 ft, and 1/2 in. PE 1,120 MBH. Use the first-stage chart for this section and the low-pressure chart after the second-stage regulator.

What pressure is a propane gas line?

In most homes, 11 in. w.c. (about 0.4 psi) after the second-stage regulator, which is what appliances are built for. Between the tank and that regulator it is about 10 psi. A 2 psi system carries 2 psi inside the house and drops to 11 in. w.c. at a line-pressure regulator near the appliances.

Can I use a natural gas pipe sizing chart for propane?

No. The tables are built for different gases. At 10 ft, 1/2 in. Schedule 40 carries about 172 MBH of natural gas (at 1,000 BTU per cubic foot) but 291 MBH of propane. A natural gas chart oversizes a propane line, and a propane chart used for natural gas undersizes it, which is the dangerous direction.

Can PE pipe be used for propane?

Yes, outdoors and underground only. It has to change to metal through an anodeless riser before it comes out of the ground, and it needs a tracer wire so it can be found later. The PE charts here are IPS pipe: 1/2 in. SDR 9.33, 1-1/4 in. SDR 10, the other sizes SDR 11.

Why do propane pipe sizing charts online show different numbers?

Most of the difference is in the heating value and the length. Charts built on 2,516 BTU per cubic foot run about 1% higher than the code tables. Charts that add 50% to the length for fittings, as some engineering references do, run lower. The charts here follow the code tables.

Propane pipe sizing chart and calculator

Inputs

Result

Propane low pressure pipe sizing chart: 11.0 in. w.c. inlet, 0.5 in. w.c. drop

Schedule 40 steel pipe, low pressure

Semirigid copper tubing (K or L), low pressure

Polyethylene (PE) pipe, underground, low pressure

Propane 2 psi pipe sizing chart: 2.0 psi inlet, 1.0 psi drop

Schedule 40 steel pipe, 2 psi

Semirigid copper tubing (K or L), 2 psi

Polyethylene (PE) pipe, underground, 2 psi

Propane first stage pipe sizing chart: 10.0 psi inlet, 1.0 psi drop

Schedule 40 steel pipe, first stage

Semirigid copper tubing (K or L), first stage

Polyethylene (PE) pipe, underground, first stage

How to use the charts

How the numbers are worked out

Propane against natural gas

Questions

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