All Cardboard Envelopes

Which cardboard envelope do you need?

Board backed envelopes are the standard choice for documents, photos, and certificates that need to stay flat. Available in manilla and white, in C4 and C5 sizes, with pre-printed "do not bend" options for anything particularly important. Our board backed envelopes range covers all the popular sizes.

Do not bend envelopes are board backed envelopes pre-printed with a do not bend instruction — important for anything where a crease or fold would cause real damage. Particularly popular for sending certificates, artwork prints, photographs, and legal documents. Available in C4, C5, and A4 formats in both manilla and white.

All board envelopes offer more rigidity than standard board backed options, made from high-grade 350gsm GD2 fully coated chipboard. A good choice where you need a premium feel alongside reliable protection — popular for sending photos, prints, and higher-value documents.

ColomPac corrugated cardboard envelopes are rigid, expandable corrugated mailers that can open up to 40mm in depth — ideal for slim but slightly bulky items that need a sturdier outer than a flat envelope can provide. Known for superior quality and consistent performance.

Mailjacket cardboard mailers are a low-cost, lightweight option modelled on the Amazon-style envelope format. Made from 100% recycled 400gsm cardboard, they offer solid protection for everyday ecommerce despatch at a price point suited to high volume.

Cardboard envelopes and Royal Mail sizing

Most cardboard envelopes are designed to sit within Royal Mail's large letter or small parcel size bands — making them a cost-effective alternative to boxes for flatter items. Getting the dimensions right before you buy can make a meaningful difference to per-item postage costs. Our Royal Mail size guide covers the exact thresholds for each band.

Not sure which option is right for your product? Our guide to choosing the right cardboard envelope covers each format in detail.