We have a handy PDF file showing engineering and map scales, and their decimal and fractional equivalents. This is an easy to use chart so you can convert to different scales. We have found this useful for converting fractional scale to feet per inch, inches per 1000 feet, inches per mile, meters per inch, acres per square inch, square inches per acre, and square mile per square inch.
Download a printable PDF version of this chart at the link below.
| Drawing Scale |
Scale Factor |
Viewport Scale |
Decimal Scale |
|---|---|---|---|
| 1/16″ = 1′-0″ | 192 | 1/192xp | .0625″ = 1′-0″ |
| 3/32″ = 1′-0″ | 128 | 1/128xp | .09375″ = 1′-0″ |
| 1/8″ = 1′-0″ | 96 | 1/96xp | .125″ = 1′-0″ |
| 3/16″ = 1′-0″ | 64 | 1/64xp | .1875″ = 1′-0″ |
| 1/4″ = 1′-0″ | 48 | 1/48xp | .25″ = 1′-0″ |
| 3/8″ = 1′-0″ | 32 | 1/32xp | .375″ = 1′-0″ |
| 1/2″ = 1′-0″ | 24 | 1/24xp | .50″ = 1′-0″ |
| 3/4″ = 1′-0″ | 16 | 1/16xp | .75″ = 1′-0″ |
| 1″ = 1′-0″ | 12 | 1/12xp | 1″ = 1′-0″ |
| 1 1/2″ = 1′-0″ | 8 | 1/8xp | 1.5″ = 1′-0″ |
| 3″ = 1′-0″ | 4 | 1/4xp | 3″ = 1′-0″ |
| DRAWING SCALE | SCALE FACTOR | VIEWPORT SCALE |
|---|---|---|
| 1″ = 10′-0″ | 120 | 1/120xp |
| 1″ = 20′-0″ | 240 | 1/240xp |
| 1″ = 30′-0″ | 360 | 1/360xp |
| 1″ = 40′-0″ | 480 | 1/480xp |
| 1″ = 50′-0″ | 600 | 1/600xp |
| 1″= 60′-0″ | 720 | 1/720xp |
| 1″ = 70′-0″ | 840 | 1/840xp |
| 1″ = 80′-0″ | 960 | 1/960xp |
| 1″ = 90′-0″ | 1080 | 1/1080xp |
| 1″ = 100′-0″ | 1200 | 1/1200xp |
We can convert your PDF files to fully layered AutoCAD DWG files.
Many times, we receive plans from customers that are reduced to a page size, or are to a scale that they can’t use. For example, they have a printout of a plan that is on a small sheet, say size 8.5×11 inches. Well, they want that same page enlarged to the full scale that it was originally. In this example we are enlarging a sheet that we don’t know the scale, to 1 inch = 4 feet, otherwise known as 1/4 scale. This sample works only as long as the proportions are in tact. If the image has been stretched in any direction, this method will not work and you will have to edit it in image editing software like Adobe Photoshop to get all dimensions to scale. Since I am in the U.S., I will be showing you this procedure using imperial measurements.
Here are the things that you will need.
We need the sheet that you are printing from to be printed out. Be sure that when you print it, to select “Actual Size” and not “Fit.” This will ensure the sheet you are measuring does not change when you print it.
The formula we use for this is simple.
WANT ÷ IS x 100 = percentage
WANT = size you want that dimension to measure
IS = the size that dimension currently measures to
PERCENTAGE = the percentage to enlarge or reduce the image
Find a large dimension on the sheet that is a full number in feet. Try to avoid a dimension like 12’9”. In my case, I have found a dimension that shows 40-feet.
Take a measurement of that dimension using your ruler and write it down. In my case, that 40-feet measures to 3 ⅞ inches. It helps if you convert the fraction to decimal. Using your calculator, divide 7 by 8 and you come up with 0.875. So the length is 3.875 inches.
Take your architectural scale and find the 1/4 side and measure up to the 40 notch. This is how long we want that dimension to be. Now measure that to see how long that is in inches. Use your ruler, and hold it up to your scale, like you can see in the photo. In my case, it measures to exactly 10-inches.
10 inches (WANT) divided by 3.875 (IS) multiplied by 100 gives us 258.06%. This formula will get you very close, but you will want to print the sheet enlarged to that percentage and measure it with your architectural scale, and adjust up or down a percentage or two.
I have also made a chart so you can find the enlargement or reduction percentage to change the scale of a plan. Here is a scale factor chart, that might help you. Check out this link from Autodesk about resizing AutoCAD plans. I hope this helps you enlarge and reduce architectural drawings. If you have any questions, please contact us. If you would like any sheets converted to AutoCAD, send it over for a quick quote.
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