Engineering and architectural drawing sizes: ANSI and ARCH explained

Drawing sheets come in three families of standard sizes. Knowing which family your drawings use makes it much easier to get an accurate quote, avoid unexpected scaling and keep a set of plans consistent from the first page to the last.

The standard sheet sizes

This is the one table to bookmark. Sizes for ANSI and ARCH are in inches. ISO sizes are in millimetres.

Which system is used where

ANSI sheets are common for engineering and mechanical drawings in North America. ANSI A is ordinary letter paper and ANSI B is tabloid, so those two are easy to print on an office machine. Larger ANSI sheets are normally plotted.

ARCH sheets are the usual choice for architectural and construction drawings. ARCH D, at 24 x 36 inches, is the most familiar plan sheet size on many job sites, and ARCH E is the large presentation size.

ISO A sizes are the metric standard in most of the world. In Oakville you may meet them on drawings from overseas consultants, equipment manufacturers or imported products. A4 and A3 are the ones most people know.

Note that the ISO and ARCH sizes are close but not the same. ISO A1 is slightly narrower than ARCH D, and ISO A0 is smaller than ARCH E. Printing an A1 drawing onto ARCH D paper changes the scale unless it is handled properly.

How to pick a size

Start from the drawing, not the paper. The size that was set up in the CAD file or drawing template is nearly always the right one, because line weights, text height and scale all depend on it.

1. Check the title block or page setup for the original sheet size.
2. Keep every sheet in one set on the same size where possible, so the set rolls and files together neatly.
3. For details that must be read on site, choose the larger size even if it is awkward to carry.
4. For sheets that only need to be reviewed, a reduced size can be perfectly useful.

If you are not sure, send us the PDF and say how it will be used. We can tell you what size it was built for.

Full size or reduced size sets

A full-size set is printed at the original sheet size, so the stated scale, such as 1/4 inch = 1 foot, holds when someone measures with a scale ruler. This is what contractors, trades and inspectors normally expect for working drawings.

A reduced-size set shrinks each sheet, often to half size. ARCH D reduces to ARCH B, and ANSI D reduces to ANSI B (11 x 17). These sets are handy for meetings, client reviews and notes, and they fit in a bag or a binder.

The catch is that a reduced drawing no longer matches its stated scale. Add a graphic scale bar to your drawing, because a bar shrinks with the sheet and stays accurate, and write 'not to scale when reduced' on reduced copies.

Avoid these common mistakes

• Printing at 'fit to page', which silently changes the scale
• Mixing sizes in the same set without telling the printer
• Assuming A1 and ARCH D are interchangeable
• Leaving out a scale bar on drawings meant for reduced copies

Our plotting CAD drawings guide walks through PDF export settings that avoid these problems.

Ordering from PrintEh

We print engineering prints and blueprint-style plans for customers in Oakville, Mississauga and Burlington, and ship across Canada and the USA. Tell us the sheet size, the number of sheets and the number of sets, and ask for a quote through our quote form. If you need to know how pricing works in general, our blueprint printing cost guide explains what affects it. Old paper sets can be converted to digital files too, as we explain in why scan large-format drawings.