What Size Should a Package Insert Be for Small Ecommerce Orders?
The Default: Why 4 by 6 Works
If you only remember one number, remember 4 by 6 inches. It is the size most small stores land on after trying others, and there are four concrete reasons why.
It fits. A 4 by 6 card slides into a standard poly mailer, a 6 by 9, a small kraft box, and most padded envelopes without bending. Very few parcels in ecommerce are too small for it.
It holds enough. You can fit a logo, an eyebrow line, a headline, two or three sentences, a discount block, and a one-inch QR code, with white space left over. That is the full anatomy of a working insert with room to breathe.
It prints cheaply. 4 by 6 is a standard photo size, which means every print shop, every online printer, and most home printers handle it without a custom quote. Photo paper and card stock both come pre-cut at this size if you want to skip trimming entirely.
It is familiar. It is postcard-shaped, so customers know instinctively that it is a message rather than paperwork. That matters more than it sounds, because a card that looks like a packing slip gets treated like one. Most OpoShop merchants who test several sizes end up back here.
The Full Size Options and When to Use Each
Every size trades content capacity against how it sits in the parcel. These five cover essentially every OpoShop order. Here is the practical guide.
- 4 by 6 inches (102 x 152 mm): The default. Headline, message, offer, and QR all fit comfortably. Start here unless you have a specific reason not to.
- A6 (105 x 148 mm): Effectively the same card in metric. Use it if you print in Europe or your shop quotes in A sizes.
- 5 by 7 inches (127 x 178 mm): More generous and reads as premium. Good for higher-priced goods and for cards where the design itself is part of the gift.
- A5 (148 x 210 mm): Half a sheet of A4. The right choice for a care guide with five or six instructions, or a folded card with content on multiple panels.
- 3.5 by 2 inches (business card): For jewellery boxes, pouches, and tiny parcels. Room for one message and one element, not both a QR and a discount code.
A worked example makes the trade concrete. A jewellery brand shipping in a 3 by 3 inch box cannot use a 4 by 6 card without folding it, and a folded card with a blank outside mostly goes unread. A business card sized insert with a QR code and four words is the correct answer there.
Meanwhile a candle brand shipping in a 5 by 5 box has room for a 4 by 6 card lying flat on top of the tissue paper, which is a much better read.
Measure the inside of your most common mailer before you decide anything. That measurement, not aesthetics, is what picks your size.
Why the QR Code Constrains Your Size
The QR code is usually the reason a small card fails on OpoShop orders, and it is worth understanding why before you commit to a size.
A printed QR needs to be about one inch square to scan reliably in the sort of light people actually open parcels in. It also needs a clear quiet zone of white space on all four sides, which in practice adds another few millimetres.
So a QR code plus its margin occupies roughly 1.2 inches square. On a 4 by 6 card that is a small fraction of the surface. On a 3.5 by 2 business card it is more than a third of the whole card, and that is before you add a label above it explaining what it does.
This is why the business card size forces a choice. You can have a QR code and a short label. You can have a discount code and a message. Trying to fit a QR, a discount code, a message, and a logo onto 3.5 by 2 inches produces a card where the QR is too small to scan and the type is too small to read.
If your parcels are genuinely tiny and you need both a code and a QR, the answer is usually a folded card rather than a smaller flat one, or moving the QR to the packaging itself.
How to Choose and Print at the Right Size
The process is short, and the important part is testing in the real parcel rather than on a screen.
Here is how those steps go in practice.
1. Design at the finished size, not scaled down
This is the most common technical mistake and it causes two problems at once.
If you design a card on a letter page and scale it down at print time, your type sizes shrink with it, so 12 point body text becomes 8 point and the QR code drops below the scannable threshold. You also usually end up with a white margin on one edge where the page was not quite proportional to the card.
Set your document to the trim size from the beginning. If the card is 4 by 6, the page is 4 by 6. A PDF where the page is the card is also exactly what a print shop wants, because there is nothing to explain and nothing to misinterpret.
2. Respect the safe margin
Commercial printing and home trimming both have tolerance. A cut can land a millimetre or two off from the intended line.
Keep all text and any QR code at least a quarter inch inside the trim on every side. If your design has a coloured background that runs to the edge, extend the colour past the trim line by an eighth of an inch so a slightly off cut does not leave a white sliver.
3. Decide flat card or tiled sheet
The layout you export depends on who is printing.
If you are sending to a print shop, one card per page at the exact trim size is correct. They will impose and cut it themselves.
If you are printing at home, you want several cards tiled on a US Letter or A4 sheet with crop marks, so you can run a stack through your printer and cut them with a guillotine. Four by six cards fit two to a letter sheet. Business cards fit ten or twelve. Generating both layouts from the same design in your OpoShop workflow saves rebuilding the card twice.
Small vs Standard vs Large: The Real Trade
Choosing a size is choosing what the card can do. The pattern below holds across most OpoShop catalogues. Here is the comparison that actually matters.
| Size | Best for | Why it works | Watch-out |
|---|---|---|---|
| 3.5 x 2 in business card | Jewellery boxes, pouches, tiny parcels | Fits anywhere and costs the least to print | A scannable QR takes a third of the card, so pick one message |
| 4 x 6 in or A6 | Almost every standard ecommerce order | Room for a message, an offer, and a QR without crowding | Too large for very small boxes without folding |
| 5 x 7 in or A5 | Care guides, premium goods, multi-step instructions | Space for several bullets and a more generous layout | Costs more per card and can overwhelm a small parcel |
The pattern across small stores is that they start too small, worrying about fitting, and then move up once they realise the card cannot hold a scannable code.
The other pattern is going too large for the sake of impact. An A5 card in a padded envelope with a single pair of socks reads as excessive, and it costs several times what a 4 by 6 does.
If your catalogue spans very different parcel sizes, running two card sizes is reasonable: a 4 by 6 for standard orders and a business card for the small ones. Keep the design and the message identical so they read as the same brand.
Fixing a Card That Prints at the Wrong Size
If your cards are coming out slightly wrong, the cause is almost always one of four things.
Your printer is scaling to fit. Most print dialogs default to "fit to page" or "shrink oversized pages," which quietly resizes your card by a few percent. Set scaling to 100 percent or "actual size" every time.
Your PDF page is not the card size. If the page is US Letter with a card drawn in the middle, you are printing a letter sheet with a card on it, and cutting becomes guesswork. The page should be the card.
Your paper size is set wrong in the driver. Printing a 4 by 6 PDF onto letter stock with the driver set to letter produces a card floating in a large white area, which is fine if you are trimming and confusing if you are not.
Metric and imperial got mixed. A6 and 4 by 6 are close but not identical, at 105 by 148 millimetres versus 102 by 152. Design for A6 and print at 4 by 6 and you get a small mismatch on both axes.
The check that catches all four takes thirty seconds. Print one card, put a ruler on it, and confirm it measures what it should. Merchants running a batch of two hundred through an OpoShop store should do this once before the batch, not after.
What to Do With the Back of the Card
Whatever size you choose, you have paid for two sides and most OpoShop stores only use one.
The reverse is the natural home for anything secondary. Care instructions belong there when the front is a thank-you. Your social handle, your website, or a short line about the brand all work.
For a reorder card, repeating the code on the back is quietly useful. Cards get put down face-down on counters, and a code visible from either side is a code that keeps working.
If you genuinely have nothing to say, put your logo centred on a coloured background. A blank white reverse makes a card feel unfinished, and a solid colour costs nothing extra when you are already printing.
What not to do is treat the back as overflow for content that did not fit the front. If your message needs both sides, your card is too small. Size up rather than splitting one thought across a flip.
Best answer: For small ecommerce orders, 4 by 6 inches is the right default: it fits standard mailers, holds a message plus a scannable one-inch QR code, and prints cheaply everywhere. Drop to business card size only for jewellery boxes and only with one message, and size up to A5 when the card is a care guide. Design at the exact trim size in your OpoShop workflow, keep everything a quarter inch inside the edge, and print one test card with a ruler on it before the batch.
If you want the page to be the card with no scaling surprises, generate the PDF at the trim size from the start.
FAQs
What is the most common package insert size?
4 by 6 inches, with A6 as the metric equivalent. It fits nearly every standard mailer, holds a headline, message, offer and QR code comfortably, and prints cheaply because it is a standard photo size. Most small stores that experiment with other sizes end up back at 4 by 6.
Can I use a business card size insert?
Yes, for jewellery boxes, pouches and very small parcels. The constraint is the QR code: a scannable one-inch code plus its quiet zone takes up more than a third of a 3.5 by 2 inch card. Pick either a QR or a discount code, not both, and keep the text to a few words.
Why is my insert PDF printing at the wrong size?
Usually because your print dialog is set to "fit to page," which scales the card by a few percent. Set scaling to 100 percent or actual size. The other common cause is a PDF whose page is US Letter with a card drawn in the middle, rather than a page that is the card.
How big does the QR code need to be on the card?
About one inch square, plus a few millimetres of clear white space on all four sides. Below that, phone cameras struggle in the dim light where people usually open parcels. This requirement is what sets the practical floor on how small your card can be.
Should I print one card per page or several on a sheet?
One card per page at the trim size if you are sending to a print shop, because that is what their workflow expects. Several tiled on a letter or A4 sheet with crop marks if you are printing at home, so you can run a stack and cut them with a guillotine.
What margin should I leave around the edge of an insert?
Keep all text and QR codes at least a quarter inch inside the trim line. Printers and trimmers both have a millimetre or two of tolerance, and anything closer than that will be clipped on some cards in a run. Extend background colour past the trim so an off cut does not leave a white sliver.
Ready to get the size right the first time? Measure your mailer, then print one test card.
