Metric vs standard chart: Metric to Standard Conversion Chart (US)

Posted on 13 августа, 2023 by alexxlab

Thread Chart (Metric) | Major and Minor Diameters

By

Lee Lechner
May 18, 2022

There are various thread types and sizes to choose from these days. Occasionally, you need to know the dimensions associated with those threads, so we’re developing posts like this one to make it easy for you.

Below you will find a quick reference chart and a more extensive list of dimensions for metric threads. The chart below will focus on the major diameters for external threads and the minor diameters for internal threads. We’ve included the image below to show these areas better.

THREAD CHART (METRIC THREADS)

Simple Thread Designation	Thread Designation	Pitch (MM)	Basic Major Diameter (External Threads)	Basic Minor Diameter (Internal Threads)
M1	M1x0.25	0.25	0.982	0.729
M2	M2x0.4	0.4	1.981	1.567
M3	M3x0.5	0.5	2.980	2.459
M4	M4x0.7	0.7	3.978	3.242
M5	M5x0.8	0.8	4. 976	4.134
M6	M6x1	1	5.974	4.917
M7	M7x1	1	6.974	5.917
M8	M8x1.25	1.25	7.972	6.647
M9	M9x1.25	1.25	8.972	7.647
M10	M10x1.5	1.5	9.968	8.376
M12	M12x1.75	1.75	11.970	10.106
M14	M14x2	2	13.960	11.835
M16	M16x2	2	15.960	13.835
M18	M18x2.5	2.5	17.960	15.294
M20	M20x2. 5	2.5	19.960	17.294
M22	M22x2.5	2.5	21.960	19.294
M24	M24x3	3	23.950	20.752
M27	M27x3	3	26.950	23.752
M30	M30x3.5	3.5	29.950	26.211
M33	M33x3.5	3.5	32.970	29.211
M36	M36x4	4	35.940	31.670
M39	M39x4	4	38.940	34.670
M42	M42x4.5	4.5	41.940	37.129
M45	M45x4.5	4.5	44. 940	40.129
M48	M48x5	5	47.930	42.587
M52	M52x5	5	51.930	46.587
M56	M56x5.5	5.5	55.930	50.046

Download Full Metric Thread Size Chart

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Metric vs. Standard

The major difference between metric and standard is in how threads are specified. When it comes to fasteners that use threading, an extra measurement called «thread pitch» is added after the diameter measurement. Examples of standard fasteners would be 1/4-20, 1/4-28, and 3/8-16. Examples of metric fasteners would be M6x1, M12x1. 75, and M18x2.5.

Standard thread pitch is how many threads there are per inch. For example, a 1/4-20 thread means the diameter of the nut or bolt is 1/4 inch and that there are 20 threads per inch.

Metric thread pitch is the distance between the threads. For example, an M18x2.5 thread means the diameter of the nut or bolt is 18 millimeters and that there are 2.5mm between the threads.

Using Chart for Choosing Masking Caps & Plugs

There are various reasons you may have needed to reference the chart, so we hope it was helpful for you! Here at Echo, we use it to help powder coaters, e-coaters, anodizers, and platers find the correct sized cap or plug for their specific thread size. So, here are a few tips in case you ever need it.

Metric Bolts | Cap It

When you need to mask off a metric threaded bolt, you’ll most likely need a silicone or EPDM rubber masking cap.

The simple version of finding the right size cap is that we suggest finding one with an ID (inside diameter) 0.4 to 0.8 millimeters smaller than the Major Diameter of the thread you’re masking off. For submersion-based processes, like e-coating, you’ll want the cap to fit tighter.

Metric Holes | Plug It

For tapered plugs, you’ll want to closely match the minor diameter to the middle diameter of the plug (see graphic). So if your hole is 6.35 millimeters in diameter, you will want the middle diameter of the plug (shown in red in the illustration here) to be right around 6.35 millimeters. If it’s not exact, seat the plug deeper in the hole. When installing these plugs, you push them in and then turn them to get a better seal.

You will want to choose a plug 0.8 millimeters bigger than the hole for pull plugs to achieve a snug fit.

About Echo Engineering

Echo Engineering has provided masking solutions to industrial finishers for well over 50 years. We specialize in not only standard catalog options, like powder coating tapes, caps, and plugs, but also in designing, engineering, and manufacturing custom solutions for some of the most prominent metal finishing lines in the world. Because of that, we are frequently working closely with paint lines to help them find ways of masking off threaded holes and bolts.

If you need a masking solution or have a question you’d like to ask us, please fill out the form below, and we will get back to you as soon as possible!

Tire Size Converter | Metric to Inch Tire Size Calculator

Metric / Inch Tire Size Converter

Enter your tire size information into one side of the tire size converter below to convert metric tire sizes to inches or inch tire sizes to their metric equivalents.

Metric and Inch Tires Sizes

While standard SAE tire sizes are easy to understand (a 35×12.50-16 tire runs 35 inches tall by 12.5 inches wide for a 16 inch wheel), many popular tires, particularly those under 35″ tall, use harder to visualize metric dimensions (a 315/75R16 tire is 315 mm wide with a sidewall height that is 75% of the width for a 16 inch wheel). Converting a metric tire to inches can be done with the equation below, however, the above calculator is much easier!

[315] / [75] R [16] = [ (Tire Width x Aspect Ratio x 2) / 2550 + Wheel Diameter ] x [ Tire Width / 25.4 ] — [ Wheel Diameter ] = [35] x [12.4] — [16]

Popular Tire Size Equivalents

Metric Tire Size		Conversion		Inch Equivalent

255 / 85 R 16	=	33 x 10. 0-16	=	33 x 10.0 — 16
285 / 75 R 16	=	33 x 11.2-16	=	33 x 11.0 — 16
285 / 70 R 17	=	33 x 11.2-17	=	33 x 11.0 — 17
305 / 70 R 16	=	33 x 12.0-16	=	33 x 12.0 — 16
305 / 65 R 17	=	33 x 12.0-17	=	33 x 12.0 — 17
315 / 65 R 17	=	33 x 12.4-17	=	33 x 12. 5 — 17
305 / 55 R 20	=	33 x 12.0-20	=	33 x 12.0 — 20
325 / 50 R 20	=	33 x 12.8-20	=	33 x 12.5 — 20

Metric Tire Size		Conversion		Inch Equivalent

275 / 65 R 20	=	34 x 10.8-20	=	33 x 11.0 — 20
285 / 75 R 17	=	34 x 11.2-17	=	34 x 11. 5 — 17
315 / 70 R 17	=	34 x 12.4-17	=	34 x 12.5 — 17
315 / 75 R 16	=	35 x 12.4-16	=	35 x 12.5 — 16
310 / 75 R 17	=	35 x 12.2-17	=	35 x 12.5 — 17
315 / 60 R 20	=	35 x 12.4-20	=	35 x 12.5 — 20
315 / 80 R 17	=	37 x 12.4-17	=	37 x 12.5 — 17
315 / 70 R 20	=	37 x 12. 4-20	=	37 x 12.5 — 20

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Helpful Tire Size Tips

If upgrading to larger tires, use our gear ratio calculator to find your recommended gear ratio.
Tire width is the maximum width of the tire which is usually at the sidewall of an inflated tire.
Tread width is the actual width of the tire tread (which is normally less than the tire width).
An «LT» after the tire size indicates that the tire is designed for «Light Truck» use.

This tire size converter is ©Copyright Crawlpedia.com — Please provide a link back to this page when copying.
Data is accurate to the best of our knowledge and is offered as-is with no guarantee.

Related Wheel and Tire Guides:

Wheel Dimensions Guide — Wheel dimensions, backspacing, and offset explained.
Wheel Bolt Pattern Guide — A list of common bolt patterns listed by vehicle and basic lug nut details.
Wheel Offset to Backspacing Conversion — A chart to convert wheel offset to backspacing.

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