B4 Envelope Size 250 × 353 mm — Custom Printing

250 × 353 mm B4 Envelope — Custom Manufacturing Options

The B4 envelope measures 250 mm wide × 353 mm high, the largest of the ISO B-series formats we manufacture. Its defining job is to carry an A4 sheet flat, with no fold — which is why it is the standard choice for contracts, certificates, artwork, and any document that must arrive uncreased. It is larger than a C4 envelope (229 × 324 mm), so it also accommodates contents with a heavier backing board or a protective sleeve.

Typical use case: A4 documents mailed flat, certificates, contracts, artwork, large brochures

All b4 envelopes listed below are manufactured to your specification — choose your paper, printing, finishing, and quantity, then request a quote for factory-direct pricing.

B4 Envelope Specifications

Dimensions are given as width × height on the finished, glued envelope.

Property	Value
Dimensions (mm)	250 × 353
Dimensions (inch)	9.84 × 13.90
International equivalent	B4 (ISO 216)
Opening style	Open end (long-edge opening, side seam)
Common paper weight	100–150 g/m² woodfree
Best for	A4 documents mailed flat, certificates and contracts

What fits inside a B4 envelope

Contents	Size (mm)	Fits inside B4?
A4 sheet, unfolded	210 × 297	Yes — flat, with margin
B5 sheet, unfolded	176 × 250	Yes — flat
A3 sheet, folded once	210 × 297	Yes — flat
A3 sheet, unfolded	297 × 420	No — too large for B4
A4 certificate or artwork	210 × 297	Yes — flat, no fold

Paper Material & Weight Options

Seven paper stocks are available for custom b6 envelopes. Every material below can be combined with your choice of printing and finishing.

Material	Available GSM (g/m²)	Best suited for
Woodfree	80, 100, 120, 140, 160, 200, 250	Everyday business — color or mono printing
Kraft yellow	80, 100, 120, 150, 180, 200, 250, 300, 350, 400	Durable & opaque — blank or single-color
Kraft white	100, 120, 150, 180, 200, 230, 250, 300	Durable & printable — premium business
Art coated	105, 128, 157, 200, 250, 300, 350	High-gloss color — promotions, invitations
Single-coated (white card)	210, 250, 300, 350	Rigid & thick — premium card enclosures
Matte art	105, 128, 157, 200, 250, 300	Low-gloss color — refined business
Pearl ice-white	120, 140, 160, 200, 250, 300, 350	Pearlescent — luxury invitations, commemorative

Printing Color Options

From blank envelopes to full-color CMYK — every printing level is available for custom b6 envelopes.

Print level	Description
Full color (4C)	Four-color CMYK — photographic quality
2 color	Two spot colors
1 color	Single-color text or logo
Blank (no print)	Plain white / kraft natural

Post-Press Finishing Processes

Every finishing option below can be applied to custom b6 envelopes. Mix and match to achieve your desired look and function.

Process	Available options
Lamination	None / Gloss (single-side) / Matte (single-side) / Anti-scratch matte / Soft-touch / Holographic
Varnish	None / Gloss varnish (single-side)
Embossing	None / Standard embossing plate / Deep embossing plate
Flat foil	None / Standard flat foil / Sculpted foil
Foil color	None / Gold / Matte gold / Red gold / Blue gold / Black gold / Silver / Custom color
Tape	None / Double-sided tape / Release tape
Self-adhesive	None / Self-adhesive (gummed flap)

Quantity Tiers & Quote Request

Configure your b6 envelope specifications above, then select a quantity tier and submit a quote request. We respond with an exact price within 24 hours. No prices are published online — every order is quoted individually based on your exact material, printing, and finishing choices.

Quantity	Action
500 pcs	Request Quote →
1,000 pcs	Request Quote →
2,000 pcs	Request Quote →
3,000 pcs	Request Quote →
5,000 pcs	Request Quote →
10,000 pcs	Request Quote →

⚠️ All prices are quoted individually. Configure your specifications above, then submit a request — we respond with an exact quote within 24 hours. No prices are displayed on this page.

Frequently Asked Questions

What size is a B4 envelope?

A B4 envelope measures 250 mm × 353 mm (width × height) on the finished, glued envelope, following the ISO 216 B-series.

Is B4 bigger than A4?

Yes. An A4 sheet is 210 × 297 mm, so B4 at 250 × 353 mm is comfortably larger — which is what allows it to hold an A4 document flat, unfolded.

What fits in a B4 envelope?

An A4 sheet flat, certificates, contracts, artwork, and large brochures. An A3 sheet fits if it is folded once.

What is the difference between B4 and C4?

C4 measures 229 × 324 mm and is sized to hold an A4 sheet flat. B4 measures 250 × 353 mm, so it is larger in both directions and leaves more room for a backing board or sleeve.

Can a B4 envelope mail at letter rate?

Generally no — B4 exceeds standard letter-size limits in most postal systems, so it normally mails in a large envelope, flat, or parcel class. Thresholds vary by service and change over time; confirm with your carrier before a large mailing.

Can B4 envelopes be made in a custom size?

Yes, but a non-standard size requires a new cutting die. If you need a dimension that is close to B4, confirm whether a stock die already covers it before ordering a custom one.

Ready to order custom B4 envelopes?

Configure your specifications and get a factory-direct quote within 24 hours. No obligation, free digital proof included.

Request a Quote → Custom Manufacturing →

Explore Other Envelope Sizes

Compare all standard envelope sizes manufactured by EnvelopeDock. Click any size for full specifications, material options, and custom ordering details.

Also see: B-Series Envelope Sizes · Business Envelopes · Printing & Finishes · Custom Manufacturing · Wholesale & Bulk Orders · Key Card Holders

B4 Envelopes