Wood Screw Size Chart

With thanks to Boltdepot.com

Screw No. Shank Diameter* Root Diameter* Maximum Head Diameter Threads Per Inch
Nearest Fractional Measurement Decimal Measurement Nearest Fractional Measurement Decimal Measurement
0 1/16 .060 3/64 .040 .119 32
1 5/64 .073 3/64 .046 .146 28
2 3/32 .086 1/16 .054 .172 26
3 7/64 .099 1/16 .065 .199 24
4 7/64 .112 5/64 .075 .225 22
5 1/8 .125 5/64 .085 .252 20
6 9/64 .138 3/32 .092 .279 18
7 5/32 .151 7/64 .102 .305 16
8 5/32 .164 7/64 .112 .332 15
9 11/64 .177 1/8 .122 .358 14
10 3/16 .190 1/8 .130 .385 13
11 13/64 .203 9/64 .139 .411 12
12 7/32 .216 9/64 .148 .438 11
14 1/4 .242 5/32 .165 .491 10
16 17/64 .268 3/16 .184 .544 9
18 19/64 .294 13/64 .204 .597 8
20 5/16 .320 7/32 .223 .650 8

*Shank diameter is measured on
the smooth portion of the
screw above the threads
.
*Root diameter is measured
between the threads and does
not include the thread height.