Buying guide · 4 min read

What size bubble mailer do you need?

How to measure for a padded envelope, why listed sizes mislead, and when a mailer is the wrong choice entirely.

Short answer

Measure your item at its longest and widest point, add roughly an inch in each direction for padding and the seal, and compare that with the mailer's usable inside size rather than its outside size. If the item is rigid, fragile or made of glass, skip the mailer and use a box.

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The options

Padded bubble mailers

Padded Bubble Mailers

Good

  • Cushioned on every side
  • Far lighter than a box, which lowers postage
  • Self-seal strip, so no tape
  • Stack flat until you need them

Trade-offs

  • No protection against crushing
  • Wrong for glass or anything rigid
  • Listed sizes often describe the outside, not the usable space

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Measure the item, not the mailer

  • Length and width at the widest points, including any bulge
  • Add about an inch to each for padding and the seal
  • For something thick, add its depth to the width as well
  • If you are between sizes, go up: a loose item is safer than a stretched seam

Usable size versus listed size

Many listings name a mailer by its outside dimensions, and the seal strip eats an inch or more of that. Look for a stated usable size. If the listing only gives one number pair, assume the inside is smaller and size up.

When to use a box instead

  • Anything glass or brittle
  • Anything rigid that would snap if the package is bent
  • Anything where a crushed corner ruins the contents
  • Anything heavy enough to tear the envelope at the seam

Packing so the padding does its job

Wrap the item so it does not slide, keep it clear of the sealed edge, and press the seal down its whole length. Padding only protects what sits inside the padded area.

Common questions

Can I reuse a bubble mailer?

Often yes if the seal strip is intact or you add tape, and if every old label and barcode is removed or covered. Scanners will read whatever they can see.

Do mailers count as packages or envelopes?

That depends on the carrier, the thickness and the weight. Check the rules of the service you buy, because the price difference is large.

Poly mailer or bubble mailer?

A plain poly mailer is lighter and cheaper but has no padding at all. It suits soft goods; a bubble mailer suits anything that can be dented.

Supplies mentioned

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