Basics · Drawing standards

Drawing paper sizes A4–A0 and common drawing scales

5 min read · updated 30 Oct 2026

ISO 216 paper sizes for technical drawings are A4 210 × 297 mm, A3 297 × 420 mm, A2 420 × 594 mm, A1 594 × 841 mm and A0 841 × 1189 mm. The scales used most in mechanical drawings are 1:1, 1:2, 1:5 and 1:10, plus 2:1 to enlarge small parts. This guide shows how to pair a sheet size with a scale and how to place the frame and title block.

A0–A4 paper sizes (ISO 216)

ISO 216 defines the A series in millimetres. The numbers below are trimmed sizes and are the starting point for every drawing frame.

Size	Width × length (mm)	Approx. area	Typical use
A0	841 × 1189	1 m²	Large machine assemblies, factory layouts
A1	594 × 841	0.5 m²	Assemblies, steel structures
A2	420 × 594	0.25 m²	Sub-assemblies, jigs and fixtures
A3	297 × 420	0.125 m²	Parts with several views, turning and milling work
A4	210 × 297	0.0625 m²	Single parts, plates, work orders

What makes the A series easy is that every size has the same ratio of long side to short side, √2 (about 1.414). Fold A0 in half across its long side and you get A1; fold A1 and you get A2, and so on, with the shape never changing. That is why an A3 drawing copied down onto A4 (at about 71%) fits the page exactly — but remember that the reduced copy is no longer at its stated scale.

An A0 sheet (841 × 1189 mm) halves into A1, A2, A3 and A4 without changing its proportions.

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What is a drawing scale?

The scale is the ratio between the size on paper and the real size of the part, written "size on drawing : real size". So 1:2 means 1 mm on paper stands for 2 mm of the real part (half size), and 2:1 means 2 mm on paper stands for 1 mm (twice size). Recommended scales for technical drawings are listed in ISO 5455.

Scale	Meaning	Good for
1:1	Full size	Parts that fit the sheet — always try this first
1:2	Half size	Medium parts, e.g. a 300–500 mm plate on A3
1:5	One fifth	Frames, machine bases, long parts
1:10	One tenth	Large assemblies, machine layouts
2:1	Twice size	Small parts or detail views, e.g. O-ring grooves, threads

The most important rule: dimension values are always real sizes, whatever the scale. A 500 mm bar drawn at 1:5 is 100 mm long on paper, but its dimension still reads 500. Nobody on the shop floor should have to measure the paper with a ruler and multiply.

Choosing the scale and the sheet together

Add up the size of all the views you need (front, side, top) plus roughly 20–30 mm around each for dimensions.
Start at 1:1. If it fits on A4 or A3, use it.
If it does not fit, go up one sheet size, or reduce the scale to 1:2 and then 1:5.
If small features become unreadable, keep the main scale and add a detail view at 2:1 or 5:1 in a free corner of the sheet.
State the main scale in the title block, and write the scale under any view that uses a different one.

Frame and title block

Drawings that go into a company's document system should have a frame and a title block on every sheet. Following ISO 5457, the thick frame line is set 20 mm in from the left edge of the paper, leaving room for filing holes, and 10 mm from the other edges. The title block sits in the bottom-right corner of the frame; ISO 7200 limits its width to 180 mm so the same block fits every size from A4 to A0.

What a title block should contain

Part name and drawing number.
Revision and revision date — matching the engineering change notice (ECN) if there is one.
Material, thickness and finish or plating.
Main scale and units (mm).
General tolerances, e.g. a reference to ISO 2768-m.
The projection symbol (first angle or third angle).
Drawn by, checked by, approved by, with dates.

Tip: a file for laser or CNC cutting should not have the frame and title block on the same layer as the part, or the machine will cut the frame too. Keep them on their own layer, or send the bare part as a separate file from the printable drawing.

Adding a frame in DXCAD2D Online

The quickest way is to let the program draw it: choose Export → PDF…, tick the drawing frame option, pick the paper size and fill in the title block fields — the frame and title block are sized to the paper and the scale is chosen for you.

To draw your own frame by hand as a reusable template:

Open DXCAD2D Online and add a layer called FRAME in the layer panel on the right.
Press R, type 0,0 Enter for the first corner, then 297,210 Enter: the edge of an A4 landscape sheet.
Draw the inner frame with another rectangle from 20,10, size 267,190 (20 mm on the left, 10 mm elsewhere).
Draw the title block in the bottom-right with rectangles and lines (Ortho F8 keeps lines square) and add Text (T): 3.5 mm for general information, 5 or 7 mm for the part name and drawing number.
Save as .json to keep it as a template; next time open it and draw the part straight into it.

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