Architectural

Scale

Factor 

Decimal

1'=1'-0"

1:1

1.0

6"=1'-0"

1:6

0.5

1-1/2"=1'-0"

1:8

0.125

1"=1'-0"

1:12

0.08333

3/4"=1'-0"

1:16

0.06250

1/2"=1'-0"

1:24

0.41667

3/8"=1'-0"

1:32

0.031250

1/4"=1'-0"

1:48

0.020833

3/16"=1'-0"

1:64

0.015625

1/8"=1'-0"

1:96

0.010417

3/32"=1'-0"

1:128

0.007813

1/16"=1'-0"

1:192

0.005208

1/32"=1'-0"

1:384

0.002604

1/64"=1'-0"

1:768

0.001302

1/128"=1'-0"

1:1536

0.000651

Engineering

Scale

Factor 

Decimal

1"=10'

1:120

0.008333

1"=20'

1:240

0.004167

1"=30'

1:360

0.002778

1"=40'

1:480

0.002083

1"=50'

1:600

0.001667

1"=60'

1:720

0.001389

1"=70'

1:840

0.001190

1"=80'

1:960

0.001042

1"=90'

1:1080

0.000926

1"=100'

1:1200

0.000833

1"=150'

1:1800

0.000555

1"=200'

1:2400

0.000416

1"=300'

1:3600

0.000277

1"=400'

1:4800

0.000208

1"=500'

1:6000

0.000166