Long Postal Boxes

Long postal boxes — square-section postal tubes for posters, prints, poles, rods and anything else that won't fit a standard box. Supplied flat in trade packs for UK sellers and online retailers. Also sold as long shipping boxes, extended-length mailers, square postal tubes or poster boxes.

Square section, and why it beats a round tube

A round mailing tube has one job: keep a rolled item rolled. It does that well and does everything else badly.

A square-section box gives you three advantages over a cylinder of similar capacity.

It won’t roll, and sorting hubs have become less forgiving about that. Carriers have automated heavily over the past couple of years, and a cylinder behaves differently to a box on a powered belt. It rolls, it turns across the direction of travel, and it can sit turning in place instead of moving along. A square section has flat faces, so it sits where it is put and travels the way it was meant to. Less movement means less damage and less chance of a delay.

Corners absorb impact. A square box crushes progressively at the corners; a tube transmits an end impact straight down its length to the contents.

It stacks and stores flat. Round tubes ship and store as rigid cylinders. These arrive flat-packed, so a pallet takes a fraction of the space and assembly is a fold and a tape.

The exception is genuinely worth naming: if your item must stay tightly rolled and nothing else, a round tube is simpler. Everything else — anything rigid, anything that shouldn't be rolled at all, anything you want to stack — is better in a square section.

When a long box is the right answer

The trigger isn't weight, it's proportion. If one dimension is far greater than the other two, a standard box wastes most of its volume and you pay a courier for the air.

Typical items:

• Posters, prints and rolled canvases — where rolling is acceptable but crushing isn't
• Blueprints, plans and architectural drawings
• Curtain poles, blinds and tracks
• Fishing rods, golf clubs and cues
• LED strips, fluorescent tubes and trim mouldings
• Banners, signage and flag poles
• Yoga mats and rolled textiles

If the item is flat rather than long — artwork that shouldn't be rolled at all — look at board backed envelopes instead, which keep it rigid and flat.

Length, girth and carrier surcharges

This is the part that costs sellers money, and it isn't obvious.

Couriers don't only price on length. Most apply a length-plus-girth rule, where girth is the distance around the parcel's cross-section. A long, thin parcel can pass the length limit and still be rejected or surcharged on the combined figure — and an oversize charge on a single parcel can exceed the cost of the box several times over.

Two practical consequences:

A narrower cross-section buys you length. Reducing the square section lets you ship a longer item inside the same combined allowance.

Limits differ by carrier and change. Length caps, girth rules and oversize surcharges vary between Royal Mail, Parcelforce, Evri, DPD, UPS, Yodel and DHL, and they get revised. Confirm the current figures with your carrier before standardising on a length — the calculation is worth doing once properly rather than discovering it on an invoice.

Choosing a size

Lengths, codes and pack quantities are in the table below. Two things decide which you need.

Measure the item, then add a little — but not much. Long boxes are unforgiving of excess length, because every extra centimetre counts toward the combined limit. Snug is better here than it is on a cube.

Check the cross-section against the widest point. A curtain pole with finials, or a rod with a reel seat, is wider than the shaft. Size on the widest part, not the average.

If none of these lengths fits what you send, we make bespoke. On long boxes that's worth more than it sounds — every surplus centimetre counts against the courier's length-plus-girth allowance, so a box cut to your product can cost less to post than a stock size you've sized up into. Send us the dimensions and we'll price it.

Buying by the pack

Supplied flat-packed in trade packs, with price breaks as pack quantities increase. Prices exclude VAT.

Long formats are the ones most suppliers run short on, because they're slow-moving and awkward to store. Over 100,000 square feet of warehousing is why we hold them in trade quantities rather than making you wait.

Long boxes are a specialist format, so most operations need one or two lengths rather than a full spread. Pick the lengths that cover your two most common items and treat anything longer as an exception to handle case by case — it's usually cheaper than carrying a length you use twice a month.

Practical detail

Single-wall corrugated construction, pre-scored and supplied flat for fast assembly. Generous flaps for secure taping or tuck-in ends. The kraft outer takes labels, direct print and barcodes cleanly, and the format is fully recyclable.

Not sure which length suits your product? Send us the dimensions of your longest and most common items and we'll work through it with you.

Delivery and returns

Order by 2pm, Monday to Friday, for same-day dispatch. Free UK mainland delivery in 1–2 working days, with a £75 minimum order. Full terms on our delivery and returns pages.