inches	mm.	inches	mm.	inches	mm.	inches	mm.	inches	mm.
-	-	1	25,4	2	50,8	3	76,2	4	101,6
1/8	3,2	1 1/8	28,6	2 1/8	54,0	3 1/8	79,4	4 1/8	104,8
1/4	6,4	1 1/4	31,8	2 1/4	57,2	3 1/4	82,6	4 1/4	108,8
3/8	9,5	1 3/8	34,9	2 3/8	60,3	3 3/8	85,7	4 3/8	111,1
1/2	12,7	1 1/2	38,1	2 1/2	63,5	3 1/2	88,9	4 1/2	114,3
5/8	15,9	1 5/8	41,3	2 5/8	66,7	3 5/8	92,1	4 5/8	117,5
3/4	19,0	1 3/4	44,4	2 3/4	69,8	3 3/4	95,2	4 3/4	120,6
7/8	22,2	1 7/8	47,6	2 7/8	73,0	3 7/8	98,4	4 7/8	123,8

Inch thread parameters

Outer diameter of the connected pipe		SAE Thread Rating	UNF thread rating	Outer thread diameter, mm	Average thread diameter, mm	Thread pitch
mm	inch					mm	threads/inch
6	1/4""""	1/4""""	7/16""""-20	11,079	9,738	1,27	20
8	5/16""""	5/16""""	5/8""""-18	15,839	14,348	1,411	18
10	3/8""""	3/8""""	5/8""""-18	15,839	14,348	1,411	18
12	1/2""""	1/2""""	3/4""""-16	19,012	17,33	1,588	16
16	5/8""""	5/8""""	7/8""""-14	22,184	20,262	1,814	14
18	3/4""""	3/4""""	1""""-14	25,357	23,437	1,814	14
18	3/4""""	---	1""""1/16-14	26,947	25,024	1,814	14
20	7/8""""	---	1""""1/8-12	28,529	26,284	2,117	12
22	7/8""""	7/8""""	1""""1/4-12	31,704	29,459	2,117	12
22	7/8""""	---	1""""3/8-12	34,877	32,634	2,117	12
25	1""""	1""""	1""""1/2-12	38,052	35,809	2,117	12

Copper conductors, wires and cables

Conductor cross-section, mm	Copper conductors, wires and cables
	Voltage, 220 V		Voltage, 380 V
	current, A	power, kWt	current, A	power, kWt
1,5	19	4,1	16	10,5
2,5	27	5,9	25	16,5
4	38	8,3	30	19,8
6	46	10,1	40	26,4
10	70	15,4	50	33,0
16	85	18,7	75	49,5
25	115	25,3	90	59,4
35	135	29,7	115	75,9
50	175	38,5	145	95,7
70	215	47,3	180	118,8
95	260	57,2	220	145,2
120	300	66,0	260	171,6

Aluminum conductors, wires and cables

Cross-section of current-carrying conductor, mm	Aluminum conductors, wires and cables
	Voltage, 220 V		Voltage, 380 V
	current, A	power, kWt	current, A	power, kWt
2,5	20	4,4	19	12,5
4	28	6,1	29	15,1
6	36	7,9	30	19,8
10	50	11,0	39	25,7
16	60	13,2	55	36,3
25	85	18,7	70	46,2
35	100	22,0	85	56,1
50	135	29,7	110	72,6
70	165	36,3	140	92,4
95	200	44,0	170	112,2
120	230	50,6	200	132,0

Inch thread sizes

	Thread diameter in mm			Thread pitch in mm	Number of threads per 1"
	outer d	average d	internal d
3/16	4,762	4,085	3,408	1,058	24
1/4	6,350	5,537	4,724	1,270	20
5/16	7,938	7,034	6,131	1,411	18
3/8	9,525	8,509	7,492	1,588	16
1/2	12,700	11,345	9,989	2,117	12
5,8	15,875	14,397	12,918	2,309	11
3/4	19,05	17,424	15,798	2,540	10
7/8	22,225	20,418	18,611	2,822	9
1	25,400	23,367	21,334	3,175	8
1 1/8	28,575	26,252	23,929	3,629	7
1 1/4	31,750	29,427	27,104	3,629	7
1 1/2	38,100	35,39	32,679	4,233	6
1 3/4	44,450	41,198	37,945	5,080	5
2	50,800	47,186	43,572	5,644	4 1/2

Nominal thread diameter in inches
	Thread diameter in mm			Thread pitch in mm	Number of threads per 1"
	outer d	average d	internal d
1/8	9,729	9,148	8,567	0,907	28
1/4	13,158	12,302	11,446	1,337	19
3/8	16,663	15,807	14,951	1,337	19
1/2	20,956	19,794	18,632	1,814	14
5/8	22,912	21,750	20,588	1,814	14
3/4	26,442	25,281	24,119	1,814	14
7/8	30,202	29,040	27,878	1,814	14
1	33,250	31,771	30.293	2,309	11
1 1/8	37,898	36,420	34,941	2,309	11
1 1/4	41,912	40,433	38,954	2,309	11
1 3/8	44,325	32,846	41,367	2,309	11
1 1/2	47,805	46,326	44,847	2,309	11
1 3/4	53,748	52,270	50,791	2,309	11
2	59,616	58,137	56,659	2,309	11

Unit conversion table

Conversion of energy units	Conversion of pressure units
1 J = 0.24 cal	1 Pa = 1 N/m*m
1 kJ = 0.28 Wh	1 Pa = 0.102 kgf/m*m
1 W = 1 J/s	1 atm =0.101 mPa =1.013 bar
1 cal = 4.2 J	1 bar = 100 kPa = 0.987 atm
1 kcal/h = 1.163 W	1 PSI = 0.06895 bar = 0.06805 atm

Conversion tables for inch to metric sizes. Thread size: table of metric and inch threads

The process of selecting the required cross-sectional sizes of threads, cables and pipes often takes a lot of time. In addition to the fact that it is necessary to select the appropriate dimensions, taking into account the parameters of the equipment, the customer has to independently convert the data into suitable units of measurement. This process requires significant time.

We simplify this task because we invite you to use ready-made translation tables. On the page of our website you will find tables that will help you easily select the necessary threads for inch pipes, copper and aluminum wires and cables. Also, you can use the translation table inch sizes in metric, thereby accurately calculating required dimensions sections.

Unfortunately, most equipment manufacturers leave the customer alone with the calculations. Therefore, a person has to independently search the Internet for translation tables in order to select optimal sizes wire sections and pipe diameters.

We value the time of our clients, providing everyone with the opportunity to use ready-made solutions. Translated in our tables standard sizes from inches to millimeters.

On this page you will also find translations of basic energy units and pressure units, therefore, you will be able to choose the right refrigeration equipment, taking into account the individual placement conditions and operating modes of the units.

Pipe diameter in inches and millimeters are very important indicators. Many have faced the problem of replacing or installing a pipeline, and finding the appropriate materials for the job.

In a huge number of offers construction market It’s difficult to understand, so before purchasing you should study in detail what the volume of pipe rolling is and how it is used in practice.

You can immediately use the online calculator below for translation without familiarizing yourself with the theory.

Online calculator to convert inches to millimeters and vice versa

An example of how to enter data into a calculator

When recording a size in inches, you should separate the whole part of the number from the fractional part (if any) with a space: for example, 10 1/4, or 20 4/8; otherwise it will be 101/4 and 204/8. Fractional numbers in millimeters are entered using a period rather than a comma (25.4 and not 25.4).

Enter the calculation data in the following. in order: left-click in the window of the corresponding parameter to cause a flickering cursor to appear; enter your numbers. The fractional part of an inch is entered without a sign.

1 Inch = 25.4 millimeters (mm). Currently, the inch, due to its clarity, is often used to measure the diameters of water-gas pipes and threads. Many parts also have dimensions in multiples of inches. In addition to whole inches, measurements are taken in quarters (1/4″), eighths (1/8″), sixteenths (1/16″), thirty-second (1/32″) fractions of an inch, etc.

If you have any questions about using online calculator, you can always ask a question in the form of a comment. We also strongly recommend that you read the instructions (located under the calculator).

How to convert inch values ​​to metric notations

The conversion of inches to metric indicators of pipe volumes is carried out using special tables. Here is an example of such a table:

To translate metric diameter pipe assortment must be rounded in the increasing direction. When performing this translation, you need to remember that according to international standards, one inch is taken into account as 2.54 cm.

With such data, translation can be performed using the simple calculator. Now that the cross-section of the pipe assortment has been calculated, its volume should be correctly calculated.

In practice, to convert the measurements of steel options, you need to take into account that the inch values ​​​​in the calculation will not be equal to the figure in mm. The reason is that when marking is applied, the internal volume is prescribed.

After this, the unit of measurement becomes the conditional passage, indicated by an integer. It is for these reasons that values ​​must be rounded to convert. It is difficult for an inexperienced master to make such a translation.

Therefore, if you need to translate these indicators, it is better to seek help from professionals, or carry out the translation using a special table as a basis. Professionals will help you translate required values, and will help you choose the right products and other parts for the pipeline.

Translation tables

When constructing highways for various purposes, different pipe materials are used: steel, copper, brass, plastic and others. All these products are distinguished by classification and measurement measures.

The overall dimensions of all pipe products are specified by the following indicators:

• Dn – outer Ø.
• Дв – internal Ø.
• h – wall thickness.

Previously, they used only steel lines, and for them they created their own sizing system. . These are its internal dimensions. That is, this indicator takes into account not only the size of the half-inch pipe billet, but also its capacity.

And the outer girth of a half-inch workpiece is 2.1 cm. Therefore, in the table near the half-inch thread, the word pipes must be added. Knowing exact dimensions half-inch and any other type of assortment, you can make it faster right choice required volumes.

This is clearly visible in the table:

Dimensions (inches)	1/2	3/4	7/8	1	1,5	2
Inner Ø (metric)	12,7	19	22,2	25,4	38,1	50,8
Thread Ø (mm)	20,4-20,7	25,9-26,2	29,9-30,0	32,7 – 33,0	45,8 – 46,2	57,9 – 58,3

Nowadays it is customary to indicate these dimensions as shown in the following table provided:

First table of diameters ( its symbolic designation is Ø, which will be further denoted in the article) pipes shows values ​​in millimeters, and the second table uses inches ( international designation – inch or in, which will be further designated in the article). An inexperienced master may ask why this is? And what designations are considered correct?

The reason is that it is applied all over the world metric system. This system is based on two indicators: conditional and nominal volume. These concepts are approached in different ways, but in the end result they show external volume. At their core, these quantities are dimensionless, but sometimes they are indicated in millimeters.

By analyzing tabular data, you can compare products from domestic manufacturers and analogues foreign production.

Interesting! The discrepancy in measurements appeared simultaneously with the input copper systems in Europe in the second half of the 20th century. In Russia at that time, standards for metal assortments were determined in mm, and not in inch; this measurement system is still widely used today.

Correspondence of two notation systems

In water and gas systems Steel pipes are widely used. Their dimensions are shown in whole quantities or their fractions. For example, the diameter of a 1-inch pipe in mm will be 33.5, and the diameter of a 2-inch pipe in mm is 67.

This of course does not correspond to the stated 25.4 and 50 mm. When laying fittings with inch markings to products of 1 and 2 inch, no difficulties arise, but replacement with plastic and copper products requires taking into account the discrepancy in the markings.

Why do they make everything so complicated? The fact is that for the formation of a liquid flow it is important to take into account inner size. For these reasons, this indicator began to be specified for 1-inch, 2-inch and all other pipe materials. The most accurate indicators are considered to be in nominal flow values.

The nominal bore of 1-inch, 2-inch and other pipe assortments is equal to the clearance dimensions. To indicate metric size 1 inch, 2 inch and any other pipeline, it is recommended to use tables.

Exact definitions - formula for calculation

This knowledge is needed to calculate the amount of transported medium. This is very important for heating systems. For example, when it is necessary to install a heating system, you need to determine and calculate the cross-sectional size of the assortment so that all housing is heated evenly.

How to accurately determine the cross-section of each pipe in quantities such as inches can be suggested by the formula: D = sqrt ((314∙Q)/ (V∙DT)).

• D – internal volume of rolled pipe;
• Q is the heat flow, which is determined in kW;
• V denotes the speed of the coolant, it is determined in m/s;
• DT is the difference temperature indicators, at the input and output of the network;
• sqrt – square root.

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Despite the presence of formulas, tables help to quickly determine Ø. This is the way to win a large number of time.

What is inch volume

Decoding the pipe diameter provided in inches is simple. They are often measured in these quantities. Such one unit is equal to 3.35 cm. It has already been indicated that the interpretation of this value has discrepancies, and this is due to the fact that the assortment is measured not by the external volume, but by the internal one. For example, the internal dimensions of an inch pipe blank can vary: from 2.55 to 2.71 cm. This value varies depending on the wall thickness.

A pipe with a size of 1 inch has an outer diameter of 25.4 mm, a pipe with a size of 2 inch is equal to 50 millimeters in metric measurement. Where in technical parameters cylindrical pipe threads take the numbers 33.249 and 66.498?

This thread on 1 and 2 inch products is performed on the outer volume. Therefore, the ratio of thread diameter to internal volume is conditional. Based on this, the dimensions of 1 and 2 inch pipe products are calculated by adding the value 25, 4 or 50 with two wall thicknesses of the pipe product.

Before decoding, you need to take into account that measurements of the product should be taken not from the outside, but from the inside. Why is this necessary? The fact is that when fastening sections of the highway from different materials, and by taking measurements only from the outside, you can get an incorrect result, which will lead to an error, since the entire range differs in the dimensions of the walls.

Also, when decoding, we must not forget that the standards of different manufacturing companies are different, they all focus on their own indicators.

If it is difficult to perform such decryption on your own, then you should seek help from professionals. They will provide effective assistance when choosing the right products.

Correspondence between metric and inch parameters

All tubular products are manufactured according to a certain standard, and the pressure indicator is a fixed value. Therefore, you need to know exactly the correspondence of the Ø of all pipes shown in inches and mm. Ignoring this correspondence, it is impossible to select the correct pipe range.

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When selecting a specific size, they are guided by the tabular information, and when replacing, we use the most approximate parameter as a guide. Exact match in two different systems There is no measurement, so pipeline elements are often equated in practice.

How this correspondence is applied in everyday life can be found in the table below:

Using this information, you can accurately determine the correspondence of two types of dimensional measurements, and take parts for work that exactly match each other.

Inch size expression

These indicators are written as a whole number, with a double stroke next to it, for example, 3“. Also, the dimensions of the pipe diameter, expressed in inches, are written as a fraction, for example, ½.

If we consider these dimensions at specific examples correspondences of Du, then they will look like this:

1. The diameter of a standard 12 inch pipe is 300.
2. The diameter of a 3 inch pipe is 80.
3. An 8 inch diameter of a standard pipe is equal to 200.
4. The diameter of a standard pipe, 32, when converted to inches is shown as 1 ¼
5. Pipe diameter 40 mm in inch is prescribed 1 ½
6. The Ø of a standard 15 inch pipe is expressed as ½
7. The Ø of a standard 4-inch product when converted to metric is 100.
8. The Ø of 3/4 inch pipe in metric conversion is 20.
9. The Ø of standard 1/2 inch pipe in metric conversion shows the number 15.

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Pipe diameters in inches and millimeters are used constantly. Knowing these dimensions, you can avoid great difficulties when connecting pipeline elements. And special tables help you find the required dimensions of the connecting parts and adjust them correctly.

Very often on the packaging (box) with a mixer, in the list of product characteristics, you can see the number 3/8 inch in the “connecting size” column.

What size is this, and how will we connect the mixer if we purchase it?

Connection size 3/8 inch, corresponds to metric thread M10. These are the dimensions of the threaded connection of the fitting part of the flexible liner. On one side of such a hose, covered in a metal braid, there is a 10 or 11 millimeter turnkey fitting and a thread at the end of 10 millimeters, or 9.5 millimeters, which corresponds to three-eighths of an inch.

This is what they look like.

First, a short fitting is screwed to the mixer, then a long one. This is so that the edges of the fittings and the thickening of the crimping do not interfere with each other.

Eat Alternative option for reinforced flexible connections these are bellows hoses for mixers. They are not much more expensive, but their service life is many times greater than the service life of a braided rubber hose. So if it's ordinary flexible liner serves 3-4 years, then bellows up to 10 years.

At the second end, the flexible hose may have a thread instead of a nut, complete with faucets, most often there is a nut, so be aware that if there is a nut at the outlet of your pipeline, you will need to purchase a nipple -