The Complete Guide to Choosing the Right Bubble Mailer Size
Choose the right bubble mailer size for your products with this complete sizing guide.
Standard UK sizes
Quick answer
Measure your product, add 10-20mm per side for clearance and bubble compression, and choose the closest standard size. Too large wastes postage and allows movement damage. Too small prevents the seal from closing properly. Stock 3-4 sizes to cover your product range. Internal dimensions are smaller than external due to the bubble lining taking up space.
How to measure
Sizing steps0 / 4 checked
Postage: postal rules or shipping costs.
Postal considerations
Sizes A-C may qualify for large letter if packed thickness stays under 25mm. Larger sizes ship as small parcels. Check total packed dimensions and weight against Royal Mail and courier thresholds.
Frequently asked questions
Measure product, add 10-20mm per side, choose the closest standard size.
A (smallest) through K (largest) in standard UK sizing.
3-4 to cover most product ranges.
Snug with 10-20mm clearance. Not loose, not forced.
Yes, bubble lining reduces internal space by 10-15mm per side.
Part of our guide
Product Guide: Bubble Mailers
Expert guides on bubble mailers and cushioned shipping envelopes for safe, efficient deliveries.
Browse all guides →
