Kraft mailer starter
Fixed 10 × 10 × 4 cm exterior format for small accessories, jewellery and samples. Low minimum order and a short lead time.
Compare both formatsInternal size targets by product type
Mailer Box Size Chart
This chart gives a minimum internal size for ten common product types, from folded apparel at 26 × 20 × 6 cm to a 300 g candle jar at 11 × 11 × 12 cm. Every value equals the packed product plus measured protection on each side plus a 2–3 mm tolerance. The numbers are planning targets, not stock sizes: confirm internal dimensions against a packed sample before ordering.
See how each size is calculated
Internal size chart by product type
Read the table from the product footprint, not from the box name. Two products with the same length and width can need different depth once an insert or a lid is added.
| Product type | Typical packed footprint | Minimum internal size (L × W × D) | What the depth covers |
|---|---|---|---|
| Folded T-shirt | 24 × 18 cm | 26 × 20 × 6 cm | Tissue on both faces, 2–3 mm tolerance |
| Hoodie or knitwear | 28 × 22 cm | 30 × 24 × 10 cm | Compression allowance, tissue wrap |
| Cosmetic set (3–5 items) | 20 × 14 cm | 22 × 16 × 8 cm | Dividers, pouch or moulded tray |
| Candle jar, 200–300 g | 9 × 9 cm | 11 × 11 × 12 cm | Jar height plus lid and top pad |
| Supplement bottle, 60 ct | 7 × 7 cm | 9 × 9 × 14 cm | Bottle height plus leaflet space |
| Mug | 12 × 9 cm | 14 × 11 × 11 cm | Handle clearance and base pad |
| Paperback book | 21 × 14 cm | 23 × 16 × 5 cm | Cover overhang and corner protection |
| Phone case or small accessory | 16 × 9 cm | 18 × 11 × 4 cm | Sleeve or foam insert |
| Chocolate bar set | 20 × 12 cm | 22 × 14 × 5 cm | Divider plus top and bottom pad |
| Jewellery box | 10 × 10 cm | 12 × 12 × 6 cm | Pouch or tissue and a shallow lid |
How to use the chart: take the row closest to your product, then replace the width and depth with your own measurements. Never scale a box up because a product "looks similar" — inserts and closures change the usable cavity.
The clearance formula behind every row
Each internal size in the chart comes from the same calculation. Run it with your own numbers before requesting a quote.
internal_length = product_length + (protection_left + protection_right) + tolerance
internal_width = product_width + (protection_front + protection_back) + tolerance
internal_depth = product_depth + (protection_bottom + protection_top) + tolerance
protection = measured thickness of tissue, wrap, pad or insert on that side
tolerance = 2–3 mm total for product variation and packing
Board thickness is not part of this formula. A 1.5 mm grey board wall reduces the usable cavity of a 26 cm exterior box by roughly 3 mm in each direction, and corrugated flutes reduce it further. Confirm exterior and internal values together.
Most common sizing error: treating a listed exterior size as usable internal space. On a small box with a lid, the difference can be 4–6 mm per side — enough to stop a product closing flat.
Three checks before you order
- Pack a real unit, not a mock-up. Fold, wrap and insert exactly as the customer will receive it, then measure the outside of that bundle.
- Weigh the packed box. Depth affects freight volume as well as fit; a 2 cm oversize adds shipping cost across a whole run.
- Confirm the packed-drop expectation. If the parcel must survive courier handling, the insert and board grade matter as much as the dimensions.
Use the mailer box size calculator to turn your measurements into a written brief, or read how to measure for a mailer box for the full method.
Compare the two mailer formats
Custom-sized mailer
Internal size built from your packed product. Suitable for apparel, candles and sets that need an insert.
See custom optionsFrequently asked questions
What is a standard mailer box size?
There is no single standard. Common working internal sizes fall between 26 × 20 × 6 cm for folded apparel and 30 × 24 × 10 cm for knitwear. Each size is derived from the packed product plus protection thickness.
Are these internal or external dimensions?
Every value in the chart is a minimum internal target. Exterior size is larger because board thickness, folds and lid geometry consume space, so ask for both numbers on a marked diagram.
How much clearance should I add for tissue paper?
Add the measured thickness on each side, typically 1–2 mm per side when folded once, plus a 2–3 mm tolerance for product variation and packing.
Can the chart be used for a mug or candle jar?
Yes, with one extra step: measure the widest point including handle or lid, add protection on each side, and allow space for an insert or divider if the item is breakable.
Do you make these sizes at low volume?
Standard boxes start at 50–100 pieces, custom printed boxes at 500 pieces, and fully custom sizes at 500–1,000 pieces. Sample orders run from 1 to 10 pieces with a 5–10 business day lead time.
Send the packed dimensions, not the product listing.
Include length, width, depth, weight, quantity and destination postcode. We reply within 24 hours with a specification and a packed freight basis.