Metric and Imperial Scale Conversions: Cheat Lists
Updated on: June 11, 2026
Issue
You're looking to convert a site plan from Imperial to metric and wondering what standard metric scale you should use in the new viewport (or vice versa). Maybe you're trying to save in a detail into your Imperial detail library that was originally metric.
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Are you new to designing in metric? Need some pointers? See our Guide to Metric Designing for Landscape.
Solution
Here's a comprehensive guide to everything Imperial to metric, and metric to Imperial, that you might use in AutoCAD for site, landscape, and irrigation plans.
Plot scale conversions
Plot scale conversions: Imperial to metric
Standard Imperial Engineering Scale
1"=10'
1"=20'
1"=30'
1"=40'
1"=50'
1"=60'
1"=70'
1"=80'
1"=90'
1"=100'
1"=150'
1"=200'
1"=300'
1"=400'
1"=500'
Actual Equivalent: Metric
1:120
1:240
1:360
1:480
1:600
1:720
1:840
1:960
1:1080
1:1200
1:1800
1:2400
1:3600
1:4800
1:6000
Closest Standard Metric Scale
1:125
1:250
1:400
1:500
1:600
1:750
1:750
1:1000
1:1000
1:1250
1:2000
1:2500
1:4000
1:5000
1:5000
Standard Imperial Architectural Scale
1' = 1'-0"
6" = 1'-0"
3" = 1'-0"
1 1/2" = 1'-0"
1" = 1'-0"
3/4" = 1'-0"
1/2" = 1'-0"
3/8" = 1'-0"
1/4" = 1'-0"
3/16" = 1'-0"
1/8" = 1'-0"
3/32" = 1'-0"
1/16" = 1'-0"
1/32" = 1'-0"
1/64" = 1'-0"
1/128" = 1'-0"
Actual Equivalent: Metric
1:1
1:2
1:4
1:8
1:12
1:16
1:24
1:32
1:48
1:64
1:96
1:128
1:192
1:384
1:768
1:1536
Closest Standard Metric Scale
1:1
1:2
1:5
1:10
1:10
1:15
1:25
1:30
1:50
1:75
1:100
1:125
1:200
1:400
1:750
1:1500
Plot scale conversions: Metric to Imperial
Standard Metric Scale
1:1
1:2
1:5
1:7.5
1:10
1:12.5
1:15
1:20
1:25
1:30
1:40
1:50
1:75
1:100
1:125
1:150
1:200
1:250
1:300
1:400
1:500
1:600
1:750
1:1000
1:1250
1:1500
1:2000
1:2500
1:3000
1:4000
1:5000
1:10000
Actual Equivalent: Arch Imperial
1' = 1'-0"
6" = 1'-0"
2 2/5" = 1'-0"
1 3/5" = 1'-0"
1 1/5" = 1'-0"
24/25" = 1'-0"
4/5" = 1'-0"
3/5" = 1'-0"
12/25" = 1'-0"
2/5" = 1'-0"
3/10" = 1'-0"
6/25" = 1'-0"
4/25" = 1'-0"
3/25" = 1'-0"
12/125" = 1'-0"
2/25" = 1'-0"
3/50" = 1'-0"
6/125" = 1'-0"
1/25" = 1'-0"
3/100" = 1'-0"
3/125" = 1'-0"
1/50" = 1'-0"
2/125" = 1'-0"
3/250" = 1'-0"
6/625" = 1'-0"
1/125" = 1'-0"
3/500" = 1'-0"
3/625" = 1'-0"
1/250" = 1'-0"
3/1000" = 1'-0"
3/1250" = 1'-0"
3/2500" = 1'-0"
Closest Std. Arch Imperial
1' = 1'-0"
6" = 1'-0"
3" = 1'-0"
1 1/2" = 1'-0"
1 1/2" = 1'-0"
1" = 1'-0"
3/4" = 1'-0"
3/4" = 1'-0"
1/2" = 1'-0"
3/8" = 1'-0"
1/4" = 1'-0"
1/4" = 1'-0"
3/16" = 1'-0"
1/8" = 1'-0"
3/32" = 1'-0"
3/32" = 1'-0"
1/16" = 1'-0"
1/32" = 1'-0"
1/32" = 1'-0"
1/32" = 1'-0"
1/32" = 1'-0"
1/64" = 1'-0"
1/64" = 1'-0"
1/64" = 1'-0"
1/128" = 1'-0"
1/128" = 1'-0"
1/128" = 1'-0"
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Actual Equivalent: Eng. Imperial
1' = 1'
1" = 0.17'
1" = 0.42'
1" = 0.625'
1" = 0.833'
1" = 1.04'
1" = 1.25'
1" = 1.667'
1" = 2.083'
1" = 2.5'
1" = 3.333'
1" = 4.17'
1" = 6.25'
1" = 8.33'
1" = 10.417'
1" = 2.5'
1" = 16.66'
1" = 20.833'
1" = 25'
1" = 33.333'
1" = 41.66'
1" = 50'
1" = 62.5'
1" = 83.34'
1" = 104.167'
1" = 125'
1" = 166.667'
1" = 208.333'
1" = 250'
1" = 333.333'
1" = 416.66'
1" = 833.333'
Closest Std. Eng Imperial
1' = 1'
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1" = 4'
-
1" = 8'
1" = 10'
1" = 15'
1" = 15'
1" = 20'
1" = 30'
1" = 30'
1" = 40'
1" = 50'
1" = 60'
1" = 80'
1" = 100'
1" = 150'
1" = 150'
1" = 200'
1" = 300'
1" = 300'
1" = 400'
1" = 1000'
Simple length conversions
You can simply google "m to ft" or "ft to m" to find a calculator. The list below includes conversions for a few common mearurements.
Simple length conversions: Imperial to metric
1" = 25.4mm
1" = 0.8333m
1' = 304.8mm
1' = 0.3048m
Simple length conversions: Metric to Imperial
1mm = 0.03937"
1mm = 0.00328'
1m = 39.3701"
1m = 3.28'