Print A1 drawings on A3, and keep the scale
A1 sets are the norm from architects; A3 is what fits in the site office and the van. The good news is that A sizes scale cleanly, so an A1 drawing on A3 is a usable scaled drawing, as long as you know what the new scale is.
Do it now with batchprint.co.ukFree in your browser. Your files stay on your computer.Open the tool →The rule
Each A size is half the area of the one above it, and every A sheet has the same proportions (1 : √2). So going down two sizes, A1 to A3, halves every length. A drawing at 1:50 on A1 is 1:100 on A3.
| Drawn on | Printed on | Size printed | 1:50 becomes | 1:100 becomes |
|---|---|---|---|---|
| A0 | A1 | 71% | 1:71 (not a standard scale) | 1:141 |
| A0 | A2 | 50% | 1:100 | 1:200 |
| A1 | A3 | 50% | 1:100 | 1:200 |
| A2 | A3 | 71% | 1:71 (not a standard scale) | 1:141 |
| A1 | A4 | 35% | 1:141 | 1:283 |
Two sizes down is always exactly 50%, a clean standard scale. One size down is 71%, which gives an odd scale you can't use with a scale rule, so treat those prints as "do not scale".
Doing it
- Add your drawings to batchprint.co.uk. A1 drawings land in the Drawings folder, set to print on A3.
- Leave Size on paper on Fit to page. A1 fills A3 at 50%, with no extra shrinking for margins.
- Keep Note the true scale ticked. Each sheet gets a line along the bottom such as "Printed at 50% - drawn 1:50, now 1:100 at A3", read from the drawing's title block where it states one scale.
Check before you measure
Printers can shrink a page slightly ("fit to printable area"). Before scaling off a print, measure a known dimension or the scale bar. If your print dialog has an Actual size or 100% option, use it for the PDF that batchprint.co.uk makes, because that PDF is already the right size.
Questions
Is an A1 drawing printed on A3 to scale?
Yes. A3 is exactly half the length and width of A1, so a 1:50 drawing becomes 1:100. Check a known dimension first in case the printer shrank the page.
What scale is A2 printed on A3?
About 71%, which turns 1:50 into roughly 1:71. That is not a standard scale, so mark those prints "do not scale".