Ask three suppliers for a quote with only a mockup image and you will likely get three different prices for three different boxes. A spec sheet is the one-page document that pins down what you want, so quotes are comparable and the first sample is right.
You do not need a packaging engineer to write one. You need to answer nine questions, and where you do not know the answer, say so and describe what the pack has to do.
Why a mockup is not enough
A mockup shows what the pack should look like. It does not say how big it is on the inside, what it is made of, how many colours are printed, which sides are printed, or what finish goes on top. Each supplier fills those gaps with their own default, and their defaults differ.
The result is quotes that look comparable but are not. One price is for E-flute with a gloss finish, another for heavier board printed both sides. A spec sheet removes the guesswork, so the only differences left between quotes are the ones that matter: price, lead time and quality.
The nine fields
- Format. The style name the industry uses: mailer box (roll-end tuck front), RSC shipping box, stand-up pouch with zipper, 12 oz single-wall paper cup. Naming the style avoids a week of back-and-forth.
- Dimensions. Length x width x height in mm, and whether they are internal or external. Suppliers usually default to internal for boxes, but say which.
- Material and grade. For boxes: board type (E-flute corrugated, folding boxboard and its weight). For pouches: film structure (for example a foil laminate or kraft with a plastic liner). For cups: paperboard weight and coating. If you do not know, write the use case ("holds 500 g of coffee, needs a barrier") and let the supplier propose.
- Print sides and coverage. Outside only, or outside and inside. Full coverage or spot. Number of colours (CMYK, CMYK plus one Pantone, one colour).
- Finish. Matte or gloss lamination, aqueous coating, soft touch, spot UV, foil, or none.
- Quantity. The order size you are quoting, and a size either side so you can see how price changes with volume.
- Artwork files. The artwork PDF on the dieline with the dieline on its own layer, plus the dieline itself and a 3D render so the supplier sees the intent.
- Special features. Window, handle, insert, tear strip, zipper, valve, hang hole.
- Delivery and timing. Where it ships to, when you need it, and whether you need a sample first.
An example
Here is a completed spec sheet for a simple mailer box. The quantities are just the volumes being quoted, not a recommendation.
| Field | Entry |
|---|---|
| Format | Mailer box, roll-end tuck front |
| Internal dimensions | 203 x 152 x 76 mm |
| Material | E-flute corrugated, white kraft outer |
| Outside only, full coverage, CMYK | |
| Finish | Matte aqueous coating |
| Quantity | 500 / 1,000 / 2,500 |
| Files | Artwork PDF with dieline layer, 1:1 dieline, 3D renders |
| Features | None |
| Delivery | Sydney, by 20 November, one sample required |
Filling it in when you do not know the answer
Most founders know the format and the size, and are unsure about everything else. That is fine. A spec sheet with honest gaps is far more useful than a confident guess.
- Material: describe weight, contents and journey. "Two glass jars, 400 g total, shipped by post" tells a supplier more than a board grade you picked at random.
- Finish: say what you want it to feel like (matte and natural, glossy and bright) and ask for options.
- Colours: if your brand uses a specific colour that must match, name the Pantone reference. Otherwise CMYK is usually fine.
- Quantity: if you are unsure, ask for prices at two or three quantities and decide once you see them.
- Timing: give a real date and say whether it is fixed (a launch) or flexible.
Write "supplier to advise" next to anything you want the supplier to recommend. Then ask each supplier to state what they assumed, so you can compare like with like. Their answers also teach you what to specify next time, so your second spec sheet will need far fewer gaps.
What goes wrong without one
- Quotes you cannot compare, because each supplier assumed a different board.
- Samples at the wrong size, because the supplier read external dimensions as internal.
- Artwork reflowed by the supplier's prepress team, because they had to rebuild your dieline.
- A finish you did not want, because nobody asked.
Each of those can cost a week or more, and some cost a full sample round.
There is a quieter cost too. Without a written spec, it is hard to reorder the same pack later. The person who handled the first order may have left, the supplier may have changed, or you may want a second supplier as a backup. A spec sheet means anyone can pick up the job and get the same result.
How to use the spec sheet once you have it
- Send the same spec sheet and files to every supplier you are asking to quote.
- Ask them to confirm the spec back or list any changes they suggest.
- When a supplier suggests a change (a different board, say), update the sheet and resend it to the others so quotes stay comparable.
- Keep the final agreed version with your order. If a sample or production run does not match, the spec sheet is what you check it against.
For the full handoff, read how to send packaging files to a printer.
Short answers
Is a spec sheet the same as a dieline? No. The dieline is the flat drawing of the pack. The spec sheet is the written description of what to make: format, size, material, print, finish, quantity and timing. A supplier needs both.
Does it have to be one page? It should be short enough to read in a minute. One page is a good target for a single product. If you have several sizes or variants, use one sheet per variant so nothing gets mixed up.
Should I include a target price? That is up to you. Some founders share a budget so suppliers can suggest cheaper materials; others prefer to see unprompted quotes first.
Who owns the final spec? You do. Suppliers will suggest changes, but the version you approve in writing is the one the order is made to, so keep it filed with the order confirmation.
What if suppliers use different names for the same thing? They often do. Describe the construction in plain words alongside the style name ("a box with a lid that tucks into the front") and attach a render, and confusion mostly disappears.
How Packaroo produces it
Every Packaroo spec pack includes a specification sheet for your project, alongside the other files a supplier needs to quote and plan production:
- the artwork on the dieline as a PDF
- the dieline at 1:1 scale with cut and crease lines
- 3D renders from four angles
- a prepress report
- CMYK artwork files a printer can edit
- a separate plate per foil or spot gloss finish, when the design uses one
You send the spec pack to whichever suppliers you choose. You can design and preview in 3D on the free plan, and a spec pack is A$15 one-time, or included in Pro and Pro Max plans. See pricing for details.
Related reading
How to read a dieline. Bleed vs safe area. How to send packaging files to a printer. Mailer box sizes.