This checklist is for anyone who’s been handed the task of ordering packaging—without being a packaging expert.

Maybe you're an office manager who just inherited supply ordering. Or an e-commerce seller who's scaling up and realizing the poly mailers you grabbed on impulse won't hold heavier products. Or a marketing coordinator who needs custom-printed boxes for a product launch.

I've been there. I manage procurement for a mid-size manufacturing company—about 60-80 orders a year across 8-10 vendors. When I took over purchasing in 2020, I made expensive mistakes because I assumed packaging is just boxes. It's not.

Here’s a 7-step checklist I’ve developed over the years. It’s not exhaustive, but it will save you from the most common pitfalls.

Step 1: Define the Job—Not the Box

This is the step most people skip. You think you need a “mailer bag,” but what you really need is something that will protect a fragile, non-square sample that needs to arrive dry. Those are different requirements.

Write down:

• What is being packed? Weight, shape, fragility, moisture sensitivity, anti-static needs?
• How is it shipped? Ground, air, overseas? Using USPS, UPS, FedEx? Carriers have size and weight limits (USPS First-Class limits flat mailers to 3.5 oz, for example).
• What’s the customer experience? Unboxing moment? Presentation? Or just get it there safely?

I once assumed a plastic mailer bag would be fine for a small circuit board sample. Turned out the customer was a QA manager who expected an ESD-safe bag. My assumption cost us the sale. (Should mention: we didn't ask them beforehand what packaging they required.)

Step 2: Map Requirements to Packaging Types

Once you know the job, match it to a package type:

• Mailer bags (poly mailers): Best for soft goods (clothing, documents, poly envelopes). Water-resistant, light, cheap. Not for heavy or sharp items.
• Carton boxes: For heavier items, multiple units, or fragile goods. Choose flute type (A, B, C, E) based on strength needs. Thick corrugated boxes (e.g., 200# test or 32 ECT) are for heavy or fragile items—but they cost more.
• Custom-printed boxes: Great for branding, but expensive if you mis-spec the size. I see this all the time: companies order custom boxes that are 50% bigger than needed, wasting space and increasing shipping costs.
• Foldable boxes with lids: Good for retail-ready packaging, subscription box products, or gift sets. They command a premium but save assembly time.

Step 3: Nail Down Dimensions—Inside and Out

This sounds obvious, but it’s where errors happen. Measure after the product is in its internal packaging (e.g., bubble wrap, foam). Add 10-15% buffer for the internal packaging itself.

For corrugated boxes, remember the dimensions are inside dimensions. For mailer bags, outside thickness matters—too tight and the seal may fail, too loose and the product shifts.

I learned this the hard way: I ordered custom boxes based on product measurements alone. Didn't account for the foam inserts we used. The boxes were 0.5" too short. The inserts wouldn't close. We had to reorder at rush pricing—50% surcharge. (Rush printing premiums are typically +25-50% for 2-3 day turnaround, based on major online printer fee structures.)

Step 4: Check Weight Ratings—Not Just Dimension Limits

A mailer bag might hold 5 lbs, but only if it's packed properly. A carton box has a bursting test (Mullen) or edge crush test (ECT) rating. For shipping, carriers use both weight and dimensional weight (DIM) pricing.

DIM weight = (Length × Width × Height) / DIM divisor. For USPS, the divisor is 166 (as of 2025). If your box is big but light, you'll be charged for dimensional weight, not actual weight. That changes your packaging cost equation.

(Per USPS pricing effective January 2025: First-Class Mail large envelope (1 oz) is $1.50. Additional ounces for large envelopes: $0.28. Source: usps.com/stamps.)

Step 5: Verify Material Compatibility with Contents

Not all mailer bags are equal:

• Polyethylene mailers: Good for general use. Not for extreme temperatures or sharp objects.
• Compostable/eco-friendly mailers: Better for brand image, but they can degrade if stored long-term or exposed to moisture. Some claim “biodegradable” without certification—check for ASTM D6400 (industrial compost) or EN 13432 (home compost).
• Carton box material: Recycled vs. virgin kraft. Recycled is cheaper but less strong and less white for printing. Virgin is stronger, more expensive, but takes print better.

I still kick myself for not verifying the compostable mailers we ordered in 2022. They looked great but started disintegrating after 6 months in storage. We had to send replacements. Cost us $800 in replacement shipping.

Step 6: Confirm Printing Requirements and Artwork Setup

If you need custom design boxes for electronics or printed mailer bags, send your artwork early and request a physical proof.

• Printing method: Digital (cheaper for small runs, 4-color standard) vs. flexographic (cheaper for large runs, limited colors). Digital is common for small to medium runs. Flexo for runs over 5,000.
• Bleed: Add 0.125" per side (so 0.25" total width/height). Otherwise the design might have white edges after cutting.
• Color matching: If your brand color is specific (e.g., exact Pantone 186C), request Pantone matching. Digital printers approximate. Offset printers can match exactly with custom ink—but that adds cost.

Per FTC advertising guidelines (ftc.gov), claims like “custom” or “eco-friendly” must be truthful and substantiated. If you print “100% recyclable” on the bag, ensure it's true for most of your customers.

Step 7: Get a Quote in Writing—and Check for Hidden Fees

Request a quote that includes:

• Unit price (with volume discounts)
• Setup fees (plate making, die cutting, tooling—often $15-75 per color)
• Shipping cost (and if it's included in the unit price)
• Minimum order quantity (MOQ)
• Lead time (standard and rush)
• Rush fee percentage (usually 25-50% for 2-3 day turnaround)

I once accepted a verbal quote for “$500 for 500 custom mailers.” After the order, the invoice read $500 for the boxes + $80 setup fee + $120 shipping + $40 for the custom color match. Total: $740. My finance department rejected the expense report because the final total didn't match my approval request. I ate the difference.

Now I ask: “What is the final total cost, including setup, shipping, and any additional fees, before I place the order?”

Common Mistakes to Avoid

1. Assuming “standard sizes” are universal. A #10 envelope is 4.125" × 9.5". But a mailer bag that says “10" × 13"” may vary by vendor by 0.5".
2. Ordering too far ahead. Storage conditions matter—especially for eco-friendly materials. Cardboard absorbs moisture, compostable bags degrade. Order 4-6 weeks before you need them, not 6 months.
3. Forgetting to test the packaging with your actual product. Drop test: drop a packed box from 3 feet at different angles. If the product breaks, the packaging is wrong.
4. Skipping the proof. Digital proofs are good. Physical proofs are better. For custom-printed boxes, always approve a physical sample.

One more thing: if you're ordering mailing bags for samples, test the seal strength. A bag that can hold 5 lbs might still leak at the seal if it's not properly heat-sealed. I've seen sample orders arrive with bags unsealed at one corner—the entire sample lost.

Hopefully this checklist gives you a clearer path. Packaging is a small part of the budget but a big part of the customer experience. It's worth the time to get it right.