✉️ C Series Paper Sizes

Q: What is the difference between C4 and DL?

C4 holds A4 paper without folding. DL holds A4 paper folded in thirds.

Complete reference for C Series envelope sizes defined by ISO 269. C0 to C8 and DL envelope dimensions, uses, and professional mailing standards. Essential for designers, printers, and businesses worldwide.

ISO 269 Standard

What is the C Series?

The C Series is a standard for envelope sizes defined by ISO 269. It is designed to hold A Series paper without folding. C Series envelopes are the professional choice for business mail, invitations, and official correspondence worldwide.

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Geometric Mean

The C Series is based on the geometric mean of the A and B Series. This ensures C Series envelopes perfectly fit A Series paper with minimal waste.

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Standardized Sizes

C0 to C8 and DL are defined in ISO 269. Each size holds the corresponding A Series size: C4 holds A4, C5 holds A5, and so on.

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Global Standard

The C Series is used worldwide for professional mail, invitations, and business correspondence. It ensures compatibility across international borders.

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Mathematical Precision

Each C size is mathematically derived from the A and B series. C4 = geometric mean of A4 and B4, ensuring perfect fit for A4 paper.

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Printing Compatibility

C Series envelopes are compatible with most professional printers and mailing equipment, making them the standard for business use.

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Mailing Efficiency

Standardized sizes reduce mailing costs and ensure documents arrive in pristine condition. C Series envelopes are recognized by postal services worldwide.

Sizes

C Series Envelope Sizes

Complete reference for all C Series envelope sizes with dimensions and what paper they hold.

C0917 × 1297 mmHolds A0

C1648 × 917 mmHolds A1

C2458 × 648 mmHolds A2

C3324 × 458 mmHolds A3

C4229 × 324 mmHolds A4

C5162 × 229 mmHolds A5

C6114 × 162 mmHolds A6

C781 × 114 mmHolds A7

C857 × 81 mmHolds A8

DL110 × 220 mmHolds A4 folded

Reference

📊 Complete C Series Size Table

Detailed comparison of all C Series envelope sizes with A Series equivalents.

Size	mm	cm	inches	Holds	Common Use
C0	917 × 1297	91.7 × 129.7	36.1 × 51.1	A0	Very large displays, posters
C1	648 × 917	64.8 × 91.7	25.5 × 36.1	A1	Large posters, presentations
C2	458 × 648	45.8 × 64.8	18.0 × 25.5	A2	Oversized mail, catalogs
C3	324 × 458	32.4 × 45.8	12.8 × 18.0	A3	Large catalogs, invitations
C4	229 × 324	22.9 × 32.4	9.0 × 12.8	A4	Standard business envelopes
C5	162 × 229	16.2 × 22.9	6.4 × 9.0	A5	Invitations, flyers
C6	114 × 162	11.4 × 16.2	4.5 × 6.4	A6	Greeting cards, invitations
C7	81 × 114	8.1 × 11.4	3.2 × 4.5	A7	Small cards, tags
C8	57 × 81	5.7 × 8.1	2.2 × 3.2	A8	Very small notes, labels
DL	110 × 220	11.0 × 22.0	4.3 × 8.7	A4 folded	Business mail, invoices

Digital Reference

📱 C Series Pixel Dimensions

C Series envelope sizes in pixels at standard resolutions.

Size	72 PPI	96 PPI	150 DPI	300 DPI
C0	2598 × 3677	3465 × 4902	5413 × 7659	10827 × 15319
C1	1837 × 2598	2449 × 3465	3827 × 5413	7654 × 10827
C2	1298 × 1837	1730 × 2449	2705 × 3827	5410 × 7654
C3	918 × 1298	1224 × 1730	1913 × 2705	3827 × 5410
C4	649 × 918	866 × 1224	1354 × 1913	2705 × 3827
C5	459 × 649	612 × 866	957 × 1354	1913 × 2705
C6	323 × 459	431 × 612	673 × 957	1346 × 1913
C7	230 × 323	306 × 431	478 × 673	957 × 1346
C8	162 × 230	215 × 306	337 × 478	673 × 957
DL	312 × 624	416 × 832	650 × 1299	1299 × 2598

Applications

✉️ C Series Envelope Uses

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Business Correspondence

C4 envelopes are the standard for business mail, official documents, and professional correspondence. They hold A4 paper without folding, ensuring documents arrive pristine.

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Invitations & Cards

C5 and C6 envelopes are popular for invitations, greeting cards, and personal correspondence. They offer a professional presentation for important communications.

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Direct Mail

DL envelopes are the most common for business mail, invoices, and marketing materials. They are designed to hold A4 paper folded in thirds, making them cost-effective for bulk mail.

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Creative Projects

C Series envelopes are used by designers and artists for portfolios, art prints, and creative projects. The standardized sizes ensure compatibility with A Series paper.

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Professional Printing

Printers use C Series envelopes for professional print jobs. The sizes ensure documents fit perfectly without trimming or waste.

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International Mail

C Series is recognized globally, making it ideal for international correspondence. Your mail will look professional in any country.

Expert Advice

💡 Professional Tips for C Series Envelopes

🎯 Choosing the Right Size

Always choose an envelope that matches your paper size without folding. For A4 documents, use C4. For folded A4 (DL), use DL envelopes. This ensures professional presentation and reduces damage during mailing.

📐 Quality Matters

Invest in high-quality envelopes with proper gussets and flaps. Professional envelopes make a lasting impression on clients and business partners.

🖨️ Printing Compatibility

Ensure your printer supports C Series envelope sizes. Check your printer's specifications before ordering large quantities.

📬 Mailing Regulations

Check with your postal service for weight and size restrictions. C Series envelopes are designed to meet international mailing standards.

♻️ Sustainability

Choose recycled or sustainably sourced envelopes where possible. Many C Series envelopes are available with FSC certification.

FAQ

❓ Frequently Asked Questions

What is the C Series standard? ▼

The C Series is defined by ISO 269 for envelope sizes. It is designed to hold A Series paper without folding. Each C size corresponds to the same A size: C4 holds A4, C5 holds A5, etc.

What is the most common C Series envelope? ▼

C4 (229 × 324 mm) is the most common business envelope, holding A4 paper without folding. DL (110 × 220 mm) is also very common for business mail with folded A4.

What is the difference between C4 and DL? ▼

C4 holds A4 paper without folding (229 × 324 mm). DL holds A4 paper folded in thirds (110 × 220 mm). DL is more compact and cost-effective for bulk mail.

What is a C5 envelope used for? ▼

C5 (162 × 229 mm) holds A5 paper without folding. It's commonly used for invitations, greeting cards, flyers, and small booklets.

What is a C6 envelope used for? ▼

C6 (114 × 162 mm) holds A6 paper without folding. It's used for greeting cards, invitations, and small correspondence.

What is the difference between C Series and A Series? ▼

A Series is for paper sizes. C Series is for envelopes designed to hold A Series paper. C Series is slightly larger than the corresponding A size to accommodate the paper.

What is the DL envelope size? ▼

DL is 110 × 220 mm (4.3 × 8.7 in). It is designed to hold A4 paper folded in thirds. DL is the most common business envelope size.

Explore

C3 to C4 C4 to C3 C5 to C4 C6 to C5 DL to C4 C4 to DL A Series B Series Paper Size Standards Envelope Sizes