Envelope sizes & formats: C6, C5, DIN Long & more

Choosing the right envelope size is crucial for sending your correspondence securely and professionally. At Kuvertwelt.de, you will find a huge selection of envelopes in all standard formats and dimensions. Whether you need classic DIN long envelopes for business mail, compact C6 envelopes for personal greetings, or large-format C4 mailing envelopes, our range covers every need. We offer not only standard DIN formats, but also exclusive square envelopes and custom special formats that are guaranteed to make your mail stand out from the crowd. Find the perfect size for your envelope now and benefit from our first-class paper quality.

The guide to envelope sizes and dimensions: How to find the right format

Finding the right size envelope can be confusing given the wide variety of sizes available. Most envelope sizes are based on the German industrial standard (DIN). These standardized sizes ensure that your contents—such as a classic DIN A4 sheet—fit perfectly into the envelope without slipping around unnecessarily. In our online shop, you will find a clear structure that helps you to quickly and easily identify the sizes of envelopes.

Overview of envelope sizes: DIN C4, C5, C6, DIN Long, and square formats at Kuvertwelt.de

An overview of the most common DIN formats

To choose the right size of envelope for your project, it is helpful to know the relationship between the A formats (content) and the C formats (envelope):

DIN C4 (229 x 324 mm): Ideal for unfolded DIN A4 documents, contracts, or catalogs.
DIN C5 (162 x 229 mm): Perfect for single-folded DIN A4 sheets or DIN A5 cards.
DIN Long (110 x 220 mm): The standard for business letters (DIN A4 sheet folded twice horizontally).
DIN C6 (114 x 162 mm): The classic size for postcards or DIN A4 sheets folded once across the middle.
DIN C7 (81 x 114 mm): The smallest standard size, ideal for small inserts or business cards.

Square envelopes and special formats

In addition to the classic DIN standards, we offer an impressive selection of square envelopes (e.g., 155x155 mm or 170x170 mm) as well as special sizes such as 120x190 mm. Square formats have a particularly modern and high-quality look, which is why they are often used for exclusive invitations or marketing mailings. When sending square envelopes, please note the postal service's postage requirements, as these are often billed as compact letters.

Quality features: More than just size

It's not just the envelope dimensions that matter, but also how they feel. At Kuvertwelt.de, you'll find envelopes in a wide variety of designs:

Different weights: Not all paper has a standard weight of 100 g/m². We stock lighter papers for optimized postage costs as well as heavy, luxurious qualities for special occasions.
Closure types: Choose between wet adhesive, pressure-sensitive adhesive (with release strip), or self-adhesive.
With or without window: depending on whether you want to use an address field on your document or write the address on the envelope by hand.

Folding technique: Which sheet fits which envelope size?

The size of an envelope determines how many times you need to fold your document. Here is a brief guide for A4 contents:

Unfolded: Use a C4 mailing envelope.
Folded once in the middle: The C5 format is the right choice here.
Folded horizontally twice (wrap fold/Z-fold): Choose the classic DIN long envelope.
Folded crosswise: The C6 envelope is ideal for this.

Personalized advice for your envelope formats

Are you unsure which envelope size is best suited to your specific project? Or are you looking for a format that you cannot find in our standard range? Our team will be happy to help! We are constantly expanding our range and can often accommodate individual requests. Simply contact us by phone or email—our experts will help you find the ideal envelope sizes for your needs.