reduction

08
Mar
2021
Reduction and Enlargement Percentage Chart

Reduction and Enlargement Percentage Chart

Architecture and engineering. Convert your plans to another scale, without math!

Enlarging plans often means you need a reduction and enlargement percentage chart. I often get asked to enlarge or reduce a plan to a specific scale. For example, an architect may ask me to enlarge a plan that is at 1 foot = 3/32 inch, to 1 foot = 1/4 inch. I deal with a lot of plans. Most of them are architectural, but also mechanical, structural, electrical and plumbing. That’s not all, I also get a lot of engineering, landscaping as well as topographic maps. I have created a reduction and enlargement percentage chart. We can convert these all from PDF to AutoCAD. I also get the dreaded question to convert metric to imperial scale, but I have already covered that.

CONVERT YOUR PDF TO CAD

I work in the reprographics industry, and often have to do this for prints. Sometimes the customer just wants their PDF enlarged, and you can do this by printing to a PDF, and specifying the percentage, and paper size. I hope this architectural scale enlargement chart helps you. Click the chart to download the full size, printable PDF version. Now resize your plans to exact scales using the chart below. Simply match your current scale with the scales on the left, and match it with the scale that you want, and there is your percentage to enlarge or reduce.

Free Enlargement and Reduction Percentage Chart

Free Enlargement and Reduction Percentage Chart
Architecture and Engineering enlargement and reduction chart. Click to download full size PDF

Looking to get your PDF converted to AutoCAD? We will convert your plans to fully layered DWG files. This service is perfect for remodels on as-built plans. For more contact us for a quote for this service. Looking for an AutoCAD scaling factor chart? Bookmark this page, because this chart is very handy for architects, engineers and reprographics / print companies.

Posted by Michael Mellor in AutoCAD tips
06
Sep
2018

I have a sheet that is not to scale, but I want it to scale

You can learn to scale an architectural plan to any scale you want

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.

  1. An architectural scale
  2. A regular inches ruler
  3. Scratch paper
  4. A calculator
Supplies needed to scale your plans
Supplies you will need to enlarge and reduce your plans to scale.

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.

measure dimension with ruler
Measure your original sheet that you are trying to enlarge

 

PDF to CAD

Send over your PDF plan to have it converted to fully layered vector CAD file.
Send Your PDF

Finding the IS

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.

Finding the WANT

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.

Measure your desired dimension on the architectural scale, with a ruler
Measure your desired dimension on with a ruler

Now we just have to do the math

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.

"Measure
Take a measurement to see if you need to enlarge or reduce a bit to get it exact.

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.

Posted by Michael Mellor