Blueprint Scale Guide and Calculator
A scale tells you how much real-world distance one unit on paper stands for. Use the calculator to convert a measurement either way, then read the guide below on keeping prints true to scale.
Architectural vs engineering scales
| Scale | Ratio | Typical use |
|---|---|---|
| 1/8″ = 1′-0″ | 1:96 | Larger floor plans, building sections |
| 1/4″ = 1′-0″ | 1:48 | Residential floor plans and elevations |
| 1/2″ = 1′-0″ | 1:24 | Enlarged plans, stairs, kitchens |
| 1″ = 1′-0″ and larger | 1:12 or larger | Details and wall sections |
| 1″ = 20′ | 1:240 | Site plans |
| 1″ = 50′ / 1″ = 100′ | 1:600 / 1:1200 | Large sites, subdivision and grading plans |
Why prints stop being to scale
- Wrong page size: a 24×36 layout exported onto a smaller page. Check with the PDF page size checker.
- “Fit to page”: shrinks the drawing a few percent to fit printer margins. Export at 100%.
- Printing at a different size: a 24×36 drawing printed on 18×24 is at 75%, so 1/4″ scale becomes 3/16″. That’s how half-size sets work; label them so nobody scales them as full size.
Always check a known dimension, or the graphic scale bar, on the printed sheet. We print at 100% from your PDF, $1.95 B&W / $3.75 color per sheet at every size. Order prints →
Frequently asked questions
What does 1/4 inch = 1 foot mean?
Every quarter inch on the drawing equals one foot in real life, a ratio of 1:48. One inch on paper is four feet.
How do I read a blueprint scale?
Find the scale in the title block or under each drawing, measure on paper, and multiply by the ratio. The calculator on this page does it both ways.
Why doesn’t my print measure correctly?
Usually the PDF page size didn’t match the paper, or fit-to-page was on. Export at 100% at the real sheet size.
Will Print My Plans prints be to scale?
Yes, when the PDF page size matches the sheet size you order. We print at 100%.
If we make a mistake, we reprint and ship it free of charge. Questions? Call (732) 701-7919 or email support@printmyplans.com.
