Socket Sizes In Order From Smallest To Largest

Quick answer: socket sizes are usually organized by drive size, then by measurement system. The most common drive sizes are 1/4-inch, 3/8-inch, and 1/2-inch. Small metric sockets commonly start around 4 mm, small SAE sockets commonly start around 5/32 inch, and larger mechanic sets often run up to 32 mm or 1-1/2 inch.

How Socket Sizes Are Organized

Socket sizing can be confusing because three things are mixed together: drive size, socket opening size, and measurement standard. The drive size is the square hole that attaches to the ratchet. The socket opening is the part that fits over the nut or bolt. The measurement standard is either metric or SAE/inch.

Drive size	Common socket range	Best use	Notes
1/4 in drive	4 mm to 14 mm, 5/32 in to 9/16 in	Small fasteners, trim, light engine work, appliances	Compact and useful in tight spaces, but not for high torque
3/8 in drive	8 mm to 22 mm, 1/4 in to 7/8 in	General automotive and garage work	The most useful all-around drive size for many DIY mechanics
1/2 in drive	10 mm to 36 mm, 3/8 in to 1-1/2 in	Lug nuts, suspension, large bolts, higher torque work	Use with appropriate torque tools and impact-rated sockets when needed
3/4 in drive and larger	Large industrial sizes	Heavy equipment, trucks, large machinery	Usually beyond normal household garage use

Metric Socket Sizes Chart

This chart lists common metric socket sizes from smallest to largest. Not every set includes every size, and specialty sizes may exist outside this list.

Order	Metric socket size	Approx. inch equivalent	Common drive
1	4 mm	0.157 in	1/4 in
2	4.5 mm	0.177 in	1/4 in
3	5 mm	0.197 in	1/4 in
4	5.5 mm	0.217 in	1/4 in
5	6 mm	0.236 in	1/4 in
6	7 mm	0.276 in	1/4 in
7	8 mm	0.315 in	1/4 or 3/8 in
8	9 mm	0.354 in	1/4 or 3/8 in
9	10 mm	0.394 in	1/4 or 3/8 in
10	11 mm	0.433 in	3/8 in
11	12 mm	0.472 in	3/8 in
12	13 mm	0.512 in	3/8 in
13	14 mm	0.551 in	3/8 in
14	15 mm	0.591 in	3/8 in
15	16 mm	0.630 in	3/8 or 1/2 in
16	17 mm	0.669 in	3/8 or 1/2 in
17	18 mm	0.709 in	3/8 or 1/2 in
18	19 mm	0.748 in	3/8 or 1/2 in
19	20 mm	0.787 in	1/2 in
20	21 mm	0.827 in	1/2 in
21	22 mm	0.866 in	1/2 in
22	23 mm	0.906 in	1/2 in
23	24 mm	0.945 in	1/2 in
24	25 mm	0.984 in	1/2 in
25	26 mm	1.024 in	1/2 in
26	27 mm	1.063 in	1/2 in
27	28 mm	1.102 in	1/2 in
28	30 mm	1.181 in	1/2 in
29	32 mm	1.260 in	1/2 in
30	34 mm	1.339 in	1/2 in
31	36 mm	1.417 in	1/2 in

SAE Socket Sizes Chart

SAE sockets use fractional inch sizes. The list below runs from smaller fractional sockets to larger sockets commonly found in mechanic sets.

Order	SAE socket size	Decimal inches	Approx. metric equivalent	Common drive
1	5/32 in	0.156 in	3.97 mm	1/4 in
2	3/16 in	0.188 in	4.76 mm	1/4 in
3	7/32 in	0.219 in	5.56 mm	1/4 in
4	1/4 in	0.250 in	6.35 mm	1/4 in
5	9/32 in	0.281 in	7.14 mm	1/4 in
6	5/16 in	0.313 in	7.94 mm	1/4 in
7	11/32 in	0.344 in	8.73 mm	1/4 or 3/8 in
8	3/8 in	0.375 in	9.53 mm	1/4 or 3/8 in
9	7/16 in	0.438 in	11.11 mm	3/8 in
10	1/2 in	0.500 in	12.70 mm	3/8 in
11	9/16 in	0.563 in	14.29 mm	3/8 in
12	5/8 in	0.625 in	15.88 mm	3/8 or 1/2 in
13	11/16 in	0.688 in	17.46 mm	3/8 or 1/2 in
14	3/4 in	0.750 in	19.05 mm	1/2 in
15	13/16 in	0.813 in	20.64 mm	1/2 in
16	7/8 in	0.875 in	22.23 mm	1/2 in
17	15/16 in	0.938 in	23.81 mm	1/2 in
18	1 in	1.000 in	25.40 mm	1/2 in
19	1-1/16 in	1.063 in	26.99 mm	1/2 in
20	1-1/8 in	1.125 in	28.58 mm	1/2 in
21	1-3/16 in	1.188 in	30.16 mm	1/2 in
22	1-1/4 in	1.250 in	31.75 mm	1/2 in
23	1-5/16 in	1.313 in	33.34 mm	1/2 in
24	1-3/8 in	1.375 in	34.93 mm	1/2 in
25	1-7/16 in	1.438 in	36.51 mm	1/2 in
26	1-1/2 in	1.500 in	38.10 mm	1/2 in

SAE To Metric Socket Conversion Chart

Use conversions as a guide, not as permission to use the wrong socket. A close metric size can round a fastener if the fit is loose, especially on rusty, soft, or high-torque hardware.

SAE size	Exact metric conversion	Closest common metric socket	Fit note
1/4 in	6.35 mm	6 mm or 7 mm	Neither is exact; use 1/4 in when possible
5/16 in	7.94 mm	8 mm	Usually close
3/8 in	9.53 mm	10 mm	10 mm may be loose on 3/8 in hardware
7/16 in	11.11 mm	11 mm	Close, but use exact size for torque work
1/2 in	12.70 mm	13 mm	13 mm may be loose
9/16 in	14.29 mm	14 mm	Can be tight; exact SAE is safer
5/8 in	15.88 mm	16 mm	Usually close
11/16 in	17.46 mm	17 mm or 18 mm	Neither is exact
3/4 in	19.05 mm	19 mm	Very close
13/16 in	20.64 mm	21 mm	Often used for lug nuts, but verify fit
7/8 in	22.23 mm	22 mm	Close
15/16 in	23.81 mm	24 mm	Close
1 in	25.40 mm	25 mm or 26 mm	Use the correct 1 in socket when possible

Which Socket Set Sizes Matter Most?

For a home garage, a useful starting point is a 1/4-inch metric set from 4 mm to 14 mm, a 3/8-inch metric set from 8 mm to 19 mm, and a 1/2-inch set that covers 17 mm, 19 mm, 21 mm, 22 mm, and larger sizes for wheels and suspension. If you work on older American equipment, add SAE sockets from 1/4 inch through 1 inch.

Common Socket Size Mistakes

Mixing drive size with socket size: a 10 mm socket can come in 1/4-inch drive, 3/8-inch drive, or even 1/2-inch drive.
Using chrome sockets on impact tools: use impact-rated sockets with impact wrenches.
Forcing a close conversion: the closest metric socket is not always safe on an SAE fastener.

Ignoring 6-point vs 12-point: 6-point sockets grip better on stubborn or rounded fasteners.
Assuming every kit is complete: many kits skip sizes such as 16 mm, 18 mm, 20 mm, or 23 mm.

Related GarageSanctum Guides

If you are building out a tool drawer, also see our American wrench size chart, bolt chart with wrench size, best socket sets for the money, and best socket organizers.

Source Notes

Conversion values use the standard inch-to-millimeter relationship of 1 inch = 25.4 mm. Socket set ranges vary by manufacturer, so treat the charts as a practical reference rather than a guarantee that every retail kit includes every listed size.