DXF to PDF

Why people turn DXF into PDF

A DXF is easy to make and hard to open: most of the people you work with don't have CAD software. A PDF opens on any laptop or phone, prints from anywhere, and keeps every line as a vector, so it stays sharp however far you zoom in. Text stays text, too, which means you can search a plan for a room name or a part number.

• Sending a drawing to a client, a builder or a supplier who only needs to look at it, mark it up or sign it off.
• Printing a plan on an office printer at A4 or A3, or taking it to a print shop.
• Attaching drawings to a quote, a tender or a permit application that asks for PDF.
• Checking a DXF that a laser shop or a mapping tool sent you, on a computer with no CAD app.
• Keeping a read-only copy next to the DXF in a project archive.

The drawing is read and drawn inside this browser tab, so a design under NDA never leaves your device. The steps further down show how to check that for yourself.

How to convert DXF to PDF

1. Set Paper and Scale above the drop area. A4 and Fit to page are already chosen, and they suit most drawings.
2. Drop your .dxf files onto the page, or use Choose file. Up to 5 convert at a time.
3. Each file gets its own row, with a progress bar while the drawing is read and drawn.
4. Select Download. With two or more files, Download all (.zip) saves them in one go.
5. Open What changed under a file to see what was approximated or left out in that drawing, with counts.

Settings are read when a file is added. To compare A3 with A4, change the paper and add the same file again; the first PDF stays as it was.

You don't have to work out which rows apply to your file: its What changed list names them. The counts come from small test drawings in two open-source projects, not from real-world plans. Of the 49 we could compare with an independent DXF reader, all but 3 reach at least 98.2% of entities drawn or approximated. These checks count what is drawn and where it lands; they don't compare the drawing line by line. The 3, and the rest of how we test, are on the DXF overview.

Two text rows belong to PDF alone. Text is set in Helvetica, one of the standard fonts every PDF reader already has, so nothing needs to be embedded and the file stays small. The cost is the character set: it covers the 218 characters of Windows Latin-1. Accented letters, °, ±, Ø, ² and ³ are in; Greek letters, ≈, ≠ and the diameter sign ⌀ are not, and each of those prints as a question mark. AutoCAD's %%c code is drawn as Ø, which the PDF can show.

Paper and scale: which to choose

Fit to page scales the drawing to fill the paper inside a 10 mm margin and centres it. The page turns to landscape when the drawing is wider than it is tall. It's the right choice for viewing, emailing and everyday printing. The scale it lands on is whatever fits, not a round ratio, so don't measure the print with a ruler.

1:1 prints the drawing at its real size: a 50 mm line is 50 mm on paper. That helps with small parts, a template to cut around, or checking a hole pattern against the real thing. It relies on the units the drawing declares. If the drawing is bigger than the paper at 1:1, the page grows to fit the drawing instead, and What changed tells you.

Drawing size makes the page exactly as big as the drawing plus the 10 mm margin, always at 1:1, so the Scale setting makes no difference here. Use it for a large-format plotter, or when the PDF will be placed inside another layout. A PDF page stops at 5080 mm (200 inches) on a side; a larger drawing is scaled down to fit, and the note gives the ratio.

A3 has twice the area of A4, which helps when a drawing has small text. Letter is the North American size. There's no 1:50 or 1:100 setting; Fit to page gives you the largest print the paper allows.

Every line is drawn 0.25 mm wide in the drawing's own colours. Colour 7, white on a dark CAD screen, prints black, and very light colours such as yellow are darkened just enough to read on white paper.

If the PDF isn't what you expected

• Question marks in some text. Those characters aren't in Windows Latin-1, and What changed counts them. DXF to SVG keeps every character.
• The page isn't the paper size you picked. At 1:1 the drawing didn't fit, so the page was sized to the drawing. Switch to Fit to page, or choose a larger paper.
• At 1:1 the print is far too small or too large. The drawing probably doesn't declare its units, so millimetres were assumed: a drawing made in inches comes out 25.4 times too small. Set the units in your CAD app (in AutoCAD, the insertion scale in the Units dialog) and save the DXF again.
• The title block or sheet notes are missing. They're probably on a layout, which isn't drawn, and What changed says how many entities were left out. Move them into model space before saving the DXF.
• The page is blank, or a part is missing. Layers that are frozen, turned off or set not to plot are left out, just as in a CAD print. Turn the layer on and save again. A drawing that lives entirely on a layout gives an empty page.
• An error instead of a PDF. Messages about binary DXF, DWG files, damaged files and drawings with too much detail are explained, with fixes, in When a DXF won't convert.

Try it with a sample file

No DXF to hand? Download sample-cad-entities.dxf (190 KB), a test sheet from the open-source dxf library with one panel per kind of entity, from arcs and splines to hatches and dimensions, and drop it into the converter above.

It makes a good tour of this page. What changed reports the pattern hatch and the leaders it approximated, notes that the drawing declares no units, and counts the characters a PDF can't show. Find the line of special characters in the PDF: ° ± Ø × ÷ ² ³ come through, and the rest turn into question marks. The sample notes give its MIT license.