# Help on how to scale up or down percentages



## GordonMitchell

Hi does anybody out there know the maths behind the percentage resizing or scaling up or scaling down a drawing or say a decal when scaning it in ,ie 1/72 scale up to 1/48 or 1/6 down to 1/12 so that you can print it off the size you want
cheers,Gordon M:thumbsup:


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## John P

Divide. For 1/72 to 1/48, do "72 divided by 48" which equals 1.5, which is 150%.

1/6 down to 1/12 is pretty obviously half the size (50%), if you look at it (6 is half of 12).


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## GordonMitchell

cheers,John P,I wasn't sure if there was multiplication in there somewhere,basically your saying I divide whatever scale the object is by the scale I want it to be and thats my percentage to increase or decrease to print out the oject......or simply you know that I know that you know that I think I'v got it....lol,thanks again now hopefully I'll remember that now,
cheers,Gordon M:thumbsup:


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## btbrush

A pair of proportional dividers and a good dial calipers are invaluable when scratch-building.


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## swhite228

For those of us who are math challenged I suggest this little gem...
its a proportion calculator and will do the work in a flash!









You can get one here (I own 2 of the calculators and use them a lot!)

http://www.geionline.com/catalogs/index.asp?category=295843

On line you could use these sites:
http://www.universalprinting.com/Calculator.aspx

or
http://www.pixus.com/itemproportioncalc.html


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## John P

^I used to live by that thing when we did our publications at work before computers.


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## swhite228

John P said:


> ^I used to live by that thing when we did our publications at work before computers.


I've bought 6 of them over the years. Most were lost to co workers who never seemed to remember where they left them after use.

I now keep 1 with my blueprint stash along with a prepaid Kinko's copy card, and the 2nd hangs on a peg on my bench next to a wall of donor kits for studio scale builds.

Makes it easy to scale the blueprints up to the correct size....match the blueprint size to the correct part size read the enlargement % and run off a copy.


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