Check window envelope position for A4
Use this free tool to check whether the address block of your A4 letter is visible in a window envelope aligned to DIN 5008. Load your PDF locally in the browser, compare the visible window area, and quickly see whether your document is ready for DIN lang, C6/5, or C5 envelopes. Ideal for invoices, business letters, reminders, and other mail sent in Germany.
210 mm
297 mm
45 mm
20 mm
90 mm
45 mm
The Window Check is a free online tool that helps you verify whether the address block of your <b>A4 PDF</b> fits a <b>window envelope following DIN 5008</b>. It runs directly in the browser and helps you avoid layout mistakes before printing invoices, offers, reminders, and business letters.
The window preview shows how the address area of your A4 document appears through the window of a standard envelope (DIN lang, C6/5, C5). The <b>red dashed line</b> on the page preview marks the area visible through the window.
You can load a <b>PDF locally in the browser</b>, select the relevant page for multi-page documents, switch between the <b>full page view</b> and the <b>envelope view</b>, and instantly see whether the address block sits inside the visible window. The empty preview also shows the <b>DIN dimensions</b> of the sheet and window area.
The window position is based on the <b>DACH standard</b> per DIN 680 / DIN 5008 / ISO 269: window <code>90 × 45 mm</code>, position <code>20 mm</code> from the left and <code>45 mm</code> from the top. This is the standard position for window envelopes in Germany, Austria, and Switzerland.
No. All processing takes place <b>entirely in your browser</b>. Your PDF is neither uploaded nor stored on any server. When you leave the page, no data is retained.
<b>DIN 5008</b> is the German standard for business letters. It specifies where the sender, recipient, date, and subject must be placed on an A4 sheet so the address area appears correctly in window envelopes. The address field must be within <code>20–110 mm</code> horizontally and <code>45–90 mm</code> vertically.
The most common formats are <b>DIN lang</b> (220 × 110 mm), <b>C6/5</b> (229 × 114 mm), and <b>C5</b> (229 × 162 mm). All use the same window position (90 × 45 mm, 20 mm from left, 45 mm from top). For A4 letters, DIN lang with tri-fold (fold lines at 99 mm and 198 mm) is used most frequently.
Yes. If your PDF contains multiple pages, you can use the page selector to inspect the exact page that will end up in the envelope. In most business letters, this is the first page with the recipient address.
Move the address block in your letter template or export layout until it falls within the highlighted window area. For DIN 5008 letters, pay special attention to the <b>20–110 mm horizontal range and 45–90 mm vertical range</b> so the recipient details remain visible in DIN lang window envelopes.
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