Precision Screwdriver Bit Sizes Guide with Charts

Screwdriver bit Sizes Guide with Charts

A full screwdriver set might seem like it has far more sizes than you will ever need, but then there comes a day when you realize that your screwdriver set is missing a size that you desperately need. It is thus better to buy the sizes that you need most rather than to buy a full set that you later find is incomplete.

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Have you ever looked at a screwdriver set and thought “There are more sizes than I’ll ever need” only to read reviews and find out they’re incomplete?

Getting a set that has the sizes you need most can often be more important than buying a “full set” that lacks one or two vital sizes. But how do you know when you have all the necessary sizes?

Below you will find the 5 most common screw head shapes with the various sizes available.

Flat Head Screwdriver Sizes

A flat head screwdriver is also sometimes referred to as a slotted screwdriver. These screwdrivers are the easiest to recognize because of its wedge-shaped end.

Tip Width (SAE)	Tip Width (Metric)
	0.8 mm
	1 mm
	1.2 mm
	1.5 mm
	1.8 mm
	2 mm
3/32"	2.5 mm
1/8"	3 mm
	3.5 mm
5/32"	4 mm
3/16"
	4.5 mm
	5 mm
7/32"	5.5 mm
	6 mm
1/4"	6.5 mm
5/16"
3/8"

Hex Key Screwdriver Sizes

These hex keys are sometimes referred to as Allen wrenches and these screwdrivers usually come in an L-shaped key with no handle. Measurements for the sizes of hex keys are done across the flat parts of the hex.

Tip Width (SAE)	Tip Width (Metric)
	.7 mm
	.9 mm
3/64"	1.2 mm
	1.3 mm
	1.5 mm
1/16"	1.6 mm
5/64"	2 mm
3/32"	2.4 mm
	2.5 mm
7/64"	2.8 mm
	3 mm
1/8"	3.2 mm
9/64"	3.5 mm
5/32"	4 mm
11/64"	4.4 mm
	4.5 mm
3/16"	4.8 mm
	5 mm
13/64"	5.2 mm
7/32"	5.5 mm
15/64"	6 mm
1/4"	6.4 mm
	7 mm
5/16"	8 mm
	9 mm
3/8"	9.5 mm
	10 mm
1/2"	12.7 mm

Robertson Screwdriver Sizes

The Robertson drive is commonly referred to as a square drive and is very popular in both electrical and construction fields. Like the Phillips screwdrivers, Robertson drives also make use of a numbering system. Robertson drives have corresponding color codes to make each size easy to identify.

Color Code	Size #	Fits Screw Sizes
Orange	#00	1-2
Yellow	#0	3-4
Green	#1	5-7
Red	#2	8-10
Black	#3	12, 1/4"
Brown	#4	5/16", 3/8"

Phillips Screwdriver Sizes

The Phillips screwdriver has become the standard in many different countries. Phillips drives have become a very popular drive when it comes to precision work, that’s why it is used in electronics and laptops. Phillips screwdrivers can be used on many different cruciform screws.

Phillips #	Tip Width (Metric)	Fits Screw Sizes
#0000	1 mm
#000	1.5 mm
#00	2 mm
#0	2.5 mm	0-1
#1	3 mm	2-4
#2	3.5 mm	5-9
#3	5 mm	10-14, 16
#4	6 mm	18, 20, 24
#5	8 mm	5/8" and 3/4" (machine screws)

Torx Screwdriver Sizes

Torx drives are designed to function at higher torques than other screwdriver types and also have a longer lifespan. The Torx drive is sometimes referred to as a star drive due to the resemblance it has with its 6-point star shape. Torx drives have different numbers based on the different distances between two opposing points.

Torx Size	Width (SAE)	Width (Metric)
T1	.031"	.81 mm
T2	.036"	.93 mm
T3	.046"	1.10 mm
T4	.050"	1.28 mm
T5	.055"	1.42 mm
T6	.066"	1.70 mm
T7	.078"	1.99 mm
T8	.090"	2.31 mm
T9	.098"	2.50 mm
T10	.107"	2.74 mm
T15	.128"	3.27 mm
T20	.151"	3.86 mm
T25	.173"	4.43 mm
T27	.195"	4.99 mm
T30	.216"	5.52 mm
T40	.260"	6.65 mm
T45	.306"	7.82 mm
T50	.346"	8.83 mm
T55	.440"	11.22 mm
T60	.519"	13.25 mm
T70	.610"	15.51 mm
T80	.690"	17.54 mm
T90	.784"	19.92 mm
T100	.871"	22.13 mm