Digitising construction plans: A0, A1, A2 – formats and resolutions explained

Before any digitisation, two questions arise: which format do my plans actually have – and at which resolution should they be scanned? Both sound more technical than they are. With this guide you will answer them in five minutes and order without any guesswork.

The DIN formats: a system with simple logic

The A-series system is ingeniously simple: each format is exactly half of the next larger one. An A1 sheet is a halved A0, an A2 a halved A1 – and so on. For construction plans, the relevant formats are above all:

Format	Dimensions	Typical use
A2	42 × 59.4 cm	Detail drawings, smaller floor plans
A1	59.4 × 84.1 cm	Floor plans, sections, elevations
A0	84.1 × 118.9 cm	Overall plans, site plans
Oversize	larger / longer than A0	Utility line plans, unfolded elevations

How to measure correctly: Unroll the plan and measure the shorter side. Around 84 cm means A0, around 59 cm A1, around 42 cm A2. If one side is longer than 119 cm or the shorter side is wider than 84 cm, it is an oversize format – simply declare it as such when ordering.

Rolled, folded, bound: everything is scannable

The condition of your plans is of secondary importance for modern large-format scanners. Rolled plans are relaxed and flattened before scanning; folded plans largely lose their creases in the digitised copy, because the scanning software removes shadow edges. Bound plan sets can also be digitised without any damage. Only with very old, brittle originals does the procedure change: they are placed by hand and transported more slowly – good to know, but at no extra effort for you.

Resolution: 200, 300 or 400 dpi?

The resolution determines how many image points per inch are captured – and thus how finely details are preserved in the digitised copy.

200 dpi is sufficient for well-preserved plans with strong lines that are primarily viewed on screen or reprinted at original size. The advantage: small files, fast loading times.

300 dpi is the all-rounder and our standard recommendation for construction plans. Annotations remain sharp even when zooming in strongly, and to-scale reprints turn out flawlessly.

400 dpi is the choice for delicate technical drawings, tight hatching, small annotations and historical plans whose fine lines must be preserved. Even when plans are later to be vectorised or redrawn in CAD, the higher resolution pays off.

A higher resolution than necessary does no harm to the content, but it noticeably increases the files – with an A0 colour scan quickly by a multiple. The golden rule: as high as necessary, not as high as possible.

Black and white, greyscale or colour?

Pure line drawings are best served in black and white: maximum contrast, minimal file size. Greyscale is recommended when area rasters, pencil entries or tinted originals are involved. Colour becomes mandatory whenever coloured information carries meaning – for instance red revision entries, colour-coded trades or stamps whose colour indicates validity. When in doubt: what must be distinguishable by colour on paper should also be so in digital form.

The right file format for the purpose

For everyday project work, PDF is the standard – every device can open it. For long-term archiving, choose PDF/A, a standardised PDF variant that will still be readable decades from now. TIFF is the lossless master format for archives and further processing. And multipage files bundle related plans – for example all storeys of a property – into a single file.

Checklist for your order

So that the order is done in two minutes: measure the shorter side and determine the format, count or estimate the quantity per format, choose the colour mode according to content, set the resolution according to the intended use and define the target format. The price calculator will then show you the reference price straight away – and the packaging guide ensures that everything reaches us intact.